Strategies for High-Risk Reoperations in Congenital Heart Disease Sameh M. Said,a and Joseph A. Dearanib Adults with congenital heart disease (CHD) is a rapidly growing group of patients, and part of this is owing to the improvement in survival for the vast majority of infants with CHD who have undergone successful surgery and live well into adult years. Residual or recurrent lesions may precipitate the need for reoperation and some patients require numerous surgical procedures or interventions over a lifetime. This article will review the surgical issues associated with reoperation in patients with CHD and discuss the different perioperative strategies that serve to decrease the risk of reoperation. Semin Thorac Cardiovasc Surg Pediatr Card Surg Ann 17:9-21 C 2014 Elsevier Inc. All rights reserved.
Introduction
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t is estimated that there are more than one million adults with congenital heart disease (CHD) in the United States alone.1 This is the result of the significant improvement in surgical techniques and perioperative care, with more than 90% of newborns with CHD surviving to adulthood.2 However, despite this improvement, residual or recurrent lesions may progress over years and decades, resulting in the need for reoperation(s). It is expected that the number of adults with CHD will continue to increase as the population increases. In this article, we will review the surgical issues related to redo cardiac surgery in patients with CHD and the different perioperative strategies to decrease the risks associated with reoperation.
Adults with CHD Adults with CHD include the following two groups: the first, which is the majority, includes those who will need reoperation to fix residual or recurrent defects or treat long-term complications (e.g., valve deterioration); and the second group includes those with previously undetected CHD who present for the first time in adulthood. The most common indications
for reoperation(s) are related to valve dysfunction, residual or recurrent intracardiac defects or arrhythmias; patients undergoing reoperation are the focus of this review. Several factors are important and contribute to perioperative mortality and morbidity with repeat cardiac operations. This includes older age, female sex, preoperative renal failure, prior history of stroke, and obesity.3 Additional factors have been identified by Park et al4 included: previous radiation, preoperative heart failure or cardiogenic shock, previous coronary artery bypass grafting, and emergency status. Inadvertent cardiotomy with significant hemorrhage encountered during redo sternotomy increases mortality dramatically to 25% versus 6.5% when there is no injury.
Preoperative Evaluation Echocardiography Echocardiography is mandatory for determining accurate diagnosis, details about valve anatomy, and ventricular function. The following are specific data pertinent to resternotomy:
Evaluating ventricular function as decreased myocardial
a
Instructor of Surgery, Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN. b Professor of Surgery, Chair, Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN. Address correspondence to Joseph A. Dearani, MD, Division of Cardiovascular Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. 55905. E-mail: [email protected]
http://dx.doi.org/10.1053/j.pcsu.2014.01.004 1092-9126/& 2014 Elsevier Inc. All rights reserved.
function has been an independent risk factor of early mortality and overall outcome.5 The presence of an intracardiac shunt or residual septal defect (atrial or ventricular level) increases the risk of air embolism if inadvertent cardiotomy occurs while the heart is fully decompressed on cardiopulmonary bypass (CPB) at resternotomy. Identifying the presence of aortic regurgitation is particularly important. When aortic regurgitation is present, 9
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Figure 1 Preoperative cross-sectional images demonstrating the relationship of the mediastinal structures to the underside of the sternum. In this particular case the ascending aorta (A) and the aortic arch (B) are eroding into the sternum. Knowledge of this preoperatively is essential when planning redo sternotomy. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
venting of the left ventricle after initiation of bypass is critical in the event that ventricular fibrillation occurs (which is expected with hypothermic bypass) to avoid subendocardial ischemia from left ventricular distension. Intraoperative transesophageal echocardiography provides guidance for peripheral cannulation and ensures proper positioning of cannulae; it helps in evaluating collapse of the cardiac chambers after initiation of peripheral CPB, provides a continuous evaluation of the contractile status and distension of the ventricle(s), and provides continuous information about intracardiac air.
preferred to CT imaging when serial studies are required over an extended period of time.
Cardiac Catheterization Cardiac catheterization is applied selectively and is most important for hemodynamic assessment (pressure measurements, vascular resistance, etc.). Knowledge of coronary artery anatomy and the presence of acquired coronary lesions
Computed Tomography (CT) Scan The relationship of cardiac structures (chambers and great vessels) to each other and to the chest wall is essential when planning reoperation. Anatomic landmarks, especially coronary arteries may be obscured, and an extracardiac conduit or dilated ascending aorta may become very close or adherent to the undersurface of the sternum or chest wall (Fig. 1). In advanced cases, preoperative imaging of these anatomic structures has demonstrated erosion into the sternum, and this significantly increases the risk of resternotomy. The recent introduction of 3-dimensional reconstructions also provides the surgeon with an anatomic model of the heart and mediastinal structures, and facilitates operative planning (Fig. 2). Magnetic Resonance Imaging (MRI) MRI provides excellent cross-sectional imaging, similar to CT scanning, and it is particularly helpful at providing additional information about cardiac chamber size and ventricular function (especially the right ventricular size and function, which is more difficult to evaluate by echocardiography). MRI has the advantage of no radiation and for this reason may be
Figure 2 CT scan with 3-D reconstruction demonstrating a dilated ascending aorta (AA) above the sinotubular junction, location of the major coronary arteries in relation to the sternum, and the presence of calcification in the aortic arch (white arrows), and to a lesser degree in the ascending and descending aorta (white patches). AA, ascending aorta; RCA, right coronary artery. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
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are critical when planning resternotomy and the potential need for coronary bypass grafting. Peripheral Access evaluation Adults with CHD have often had multiple prior invasive diagnostic and/or therapeutic procedures that result in scarring, stenosis, and obstruction of peripheral arterial and venous structures in the neck and/or the groin. Knowledge of patency of peripheral vasculature is critical because peripheral cannulation for CPB becomes a strategic alternative during a hazardous resternotomy. This can be done using ultrasound or other cross-sectional imaging studies. The following alternative cannulation sites may be considered if there is a high risk of cardiac injury at resternotomy: ■ ■ ■ ■ ■ ■ ■ ■
Femoral artery or vein vessels Iliac artery or vein vessels Axillary artery Internal jugular vein (usually right) Right atrium or ascending aorta (via right thoracotomy) Left ventricular apex (via left thoracotomy) Pulmonary artery (via left thoracotomy) Abdominal aorta
Timing of Resternotomy The time period since last sternotomy plays an important role in the degree and quality of mediastinal adhesions. Reoperation in the first 6 to 12 months has been associated with worse outcome because of vascularity and immaturity of adhesions, which causes mediastinal dissection to be more difficult. In general, the greater the time period between the reoperation from the previous operation, the less dense and less vascular the adhesions, which can minimize bleeding and its related morbidities. In addition to factors related to the duration between operations, it is important to advise reoperation before the onset of significant ventricular dysfunction. This is particularly important when there are regurgitant valve lesions that result in progressive ventricular dilatation and dysfunction. Timely referral to surgery before the onset of significant ventricular dysfunction can also help reduce perioperative morbidity and mortality.
Surgical Technique of Resternotomy Accurate preoperative assessment and communication with other team members, including the cardiologist, anesthesiologist, perfusionist, and operating room team, is an important element to success with reoperation. Our strategy includes:
If there is a high risk of injury to the heart or great vessels with resternotomy, peripheral cannulation of femoral or axillary vessels is preferred. This is determined by preoperative evaluation of cross-sectional imaging and the close relationship of these structures to the posterior
sternum. Although percutaneous techniques facilitate right internal jugular and groin cannulation with almost no need for an incision in the case of emergency (Fig. 3), we prefer cutdown exposure of groin vessels so that repair can be accomplished under direct vision at the time of cannula removal. Additional venous return can be achieved with a percutaneous cannula advanced into the right superior vena cava from the right internal jugular vein before resternotomy; this is also helpful if bicaval cannulation is going to be required for the planned procedure. Selective use of vacuum-assisted venous drainage is helpful; however, it should be avoided or used with extreme caution in the presence of residual intracardiac shunts to minimize the risk of air embolism, especially if there is injury to a right-sided cardiac chamber during resternotomy. In this situation, it is essential to avoid vacuum-assist and maintain a positive central venous pressure of 46 to 8 mmHg to avoid air entry into a decompressed right heart and subsequent paradoxical embolism across the shunt. Other measures to minimize the risk of air embolism include: routine use of an aortic root vent (after sufficient mediastinal dissection is complete), Trendelenburg position, and flooding the operative field with carbon dioxide. If the aorta, pulmonary venous atrium, or other left-sided structure is injured, then CPB and deep hypothermia with possible circulatory arrest may become necessary to facilitate safe resternotomy. Based on the relationship between the heart and great vessels to the back of the sternum, initiation of CPB may be considered prior to resternotomy (Fig. 4). This does not necessarily protect the right ventricle from injury; however, it has several advantages: it provides decompression of the right heart, creates a more controllable hemodynamic situation, minimizes the amount of blood loss if injury occurs, and can facilitate mediastinal dissection. This is particularly helpful when there is significant right heart enlargement or elevated right-sided intracardiac pressures. If bypass is initiated before resternotomy to facilitate safe reentry, a decision then needs to be made as to whether bypass can be safely discontinued after resternotomy to allow mediastinal dissection. This reduces a more prolonged bypass time that can contribute to additional morbidity and mortality. Alternatively, in some situations, maintenance and continuation of bypass may further facilitate mediastinal dissection. The use of pericardial substitutes has been controversial6,7; we have a low threshold to use Gore-Tex pericardial membrane if additional reoperation(s) are expected in the future. A previous report from our institution identified that the incidence of injury is reduced if the native pericardium was approximated during the prior surgical procedure.4 We have found the use of biological substitutes to be more challenging with greater scar tissue and adhesions at a subsequent operation.
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Figure 3 Intraoperative photographs showing the cutdown technique of femoral cannulation in preparation for cardiopulmonary bypass prior to redo sternotomy. (A) Small oblique groin incision is performed to expose the femoral vessels and Seldinger technique using a guidewire is performed with purse string sutures on each of the vessels. (B) The puncture site is then dilated over the guidewire before insertion of the cannula. (C) The femoral arterial and (D) femoral venous cannulae are inserted and secured in place with the final position of the venous cannula confirmed using intraoperative transesophageal echocardiography. When the femoral artery is noted to be small and the femoral arterial cannula would result is occlusion of the femoral artery distally, a chimney graft is sewn end-to-side to the femoral artery so antegrade perfusion of the distal leg is preserved. One or both groins can be cannulated based on vascular anatomy. Frequent postoperative examination of distal pulses and extremity perfusion are essential to identify potential compartment syndrome. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Controversy exists regarding the need to remove or retain
the previously placed sternal wires during the actual sawing of the sternum (Fig. 5A). There is no conclusive evidence that cardiac injury is decreased with keeping them intact; the decision is generally based on surgeon preference. Sternal redivision options include a pneumatic microsagittal saw (Fig. 5A) to completely divide entire sternum, or just divide the anterior sternal table followed by careful division of the posterior table with a heavy scissors under direct vision. The use of Volkmann retractors can facilitate elevation of the lower two halves
of the sternum (Fig. 5B). The microsagittal saw has the advantage of precise perpendicular division of the sternum, with relatively easy control of the depth of blade penetration and the ability to feel the posterior sternal table.8 The heart and great vessels should be gently released in a stepwise fashion from the back of the sternum (beginning inferiorly) with a combination of sharp scissors dissection and low-energy electrocautery to allow safe separation of the two sternal halves and release of mediastinal structures from the chest wall. We intentionally enter each pleural
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Figure 4 Preoperative cross-sectional imaging with 3-dimensional reconstruction demonstrating (A) a proximal right coronary artery aneurysm; (B, C) The same patient also has a severe pectus deformity with the mediastinal structures displaced into the left hemithorax; (D) 3-dimensional reformat showing the relationship of the leftward position of the right coronary artery aneurysm to the sternum. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
space to allow a complete release of mediastinal structures and reduce tension on the innominate vein. This allows safe placement and spreading of the sternal retractor (Fig. 5C). A valuable alternative that is now our preferred technique is the use of the craniotome (Midas Rex Microsaw; Medtronic, Minneapolis, MN) to perform resternotomy (Fig. 6). This requires removal of all wires prior to division. Some degree of dissection at both the superior or inferior aspect of the sternum is required before engaging the microsaw under the sternum (Fig. 7). The ergonomically designed handpiece facilitates easy and precise control of the saw, and the thin
rotating blade with the protective distal flange minimizes the risk of injury to mediastinal structures. We have not encountered a single cardiac injury from this saw with sternal re-entry using this technique. It is important to be cautious with cephalad retraction of the successfully divided sternum during takedown of adhesions to avoid a “retraction tear” of the right atrium or right ventricle. Limiting dissection only to the necessary areas of the intended procedure is an important consideration as it decreases the risk of injury to cardiac structures, and results in less bleeding from dissected areas at the end of the procedure.
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Figure 5 Intraoperative photos demonstrating our technique of resternotomy when using a microsagittal saw. (A) The microsagittal saw is helpful during redo sternotomy because of its ease of handling. (B) Rake retractors are placed at the level of the xiphoid and towel clips are used on either side of the sternum to elevate the corresponding half during the resternotomy. (C) In general, we use the saw for division of the anterior sternal table and heavy blunt scissors to divide the posterior table with the help of Volkmann retractors to elevate the sternum so the posterior table is divided under direct vision. After dividing the posterior sternal table, the mediastinal structures are dissected and released redivision. The rotating blade is small (wide arrow) and is protected from the heart by the flanged lip distally, which allows precise and safe redivision of the sternum. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Figure 6 (A and B) Intraoperative photos showing the alternative use of the craniotome (Midas Rex Microsaw), which is our current preferred technique of sternal division.
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Figure 7 Intraoperative photos showing the technique of sternal division using the craniotome: (A) the sternal wires have to be removed, and the either the superior edge of the sternum (B), or the subxiphoid end (C) can be used to engage the craniotome. The smaller blade allows precise control and minimizes injury to surrounding mediastinal structures during resternotomy.
Strategies for Safe Peripheral Cannulation Peripheral cannulation represents an important strategy to facilitate sternal redivision and reduce the incidence of injury to cardiac and/or other mediastinal structures during complex resternotomy. Several sites have been suggested as previously mentioned; however, concerns related to peripheral cannulation (especially lower extremity vessels) include leg ischemia, compartment syndrome, or retrograde dissection from femoral artery cannulation. The following represents our current strategy to minimize morbidity related to peripheral cannulation:
Proper preoperative evaluation of peripheral vessels using
ultrasonography or cross-sectional imaging, especially with multiple prior reoperations or groin interventions that increases the chance of encountering difficulty during repeat groin vessel cannulation. We tend to prefer the right groin for cannulation. It is important to emphasize that the ideal peripheral cannulation allows antegrade perfusion of the instrumented lower extremity and satisfactory venous return of
that same extremity. This requires not oversizing the femoral venous cannula that would result in femoral venous obstruction. Antegrade perfusion of the leg with inadequate femoral venous outflow can result in compartment syndrome. Compartment syndrome can also result from an oversized femoral arterial cannula that causes obstruction and inadequate distal femoral artery perfusion. Consideration to utilizing both groins for arterial and venous cannulation may minimize extremity complications. Once adequate mediastinal dissection is accomplished, conversion to central cannulation should be performed to minimize or avoid extremity complications. If the femoral artery is small, the use of Chimney graft is helpful to ensure bidirectional flow in the femoral artery up and down the lower extremity to avoid leg ischemia. Use of the axillary artery with a chimney graft represents a safe alternate cannulation site. Several advantages for axillary artery over femoral artery cannulation exist: (1) it provides antegrade flow that is associated with lower stroke rate and of value in those with diseased and atherosclerotic aorta; (2) the axillary artery is usually free
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Figure 8 Our current coagulation test-based intraoperative transfusion protocol that served to minimize transfusion requirements significantly.
of atheroma, which makes it an ideal site for cannulation; (3) facilitates selective antegrade cerebral perfusion during aortic arch surgery; and (4) the use of a side arm graft has decreased the morbidity associated with direct axillary artery cannulation. Early conversion to central cannulation should be the rule to minimize morbidity related to peripheral cannulation because of the size of peripheral vessels or the duration of the CPB.
Blood Transfusion Algorithm Transfusion of blood and/or blood products has been an independent risk factor associated with increased morbidity and mortality after cardiac surgery.9 This becomes critically important because abnormal bleeding is common with complex reoperations because of the extensive mediastinal adhesions and dissection, and potentially long bypass times that result in associated coagulation abnormalities. The decision to transfuse and which product required is often difficult under these circumstances and treatment most of the time is empirical. In an effort to minimize transfusions of blood and its related products and the associated risks, we developed a coagulation test-based transfusion algorithm that is based on a large prospective randomized study in over 800 patients (Fig. 8). This has demonstrated a significant reduction in allogenic RBC, platelet, and fresh frozen plasma transfusions compared with the control group.10
Right Thoracotomy for Reoperation Right thoracotomy can be a useful alternative to a high-risk resternotomy and it is applicable for approaches to the mitral and/or the tricuspid valves. It avoids major hemorrhagic complications of resternotomy, including inadvertent cardiotomy, or injury to previous patent bypass grafts, extracardiac conduits, or the aorta. This can be performed using aortic occlusion and cardioplegic arrest, fibrillatory arrest, or the beating heart techniques depending upon the procedure. Additional advantages include minimal mediastinal dissection, which may further decrease CPB time and transfusion requirements.11 Limitations with this approach can include scarring from prior right thoracotomy, large body habitus or obesity, control of the aorta and application of the cross clamp, and the de-airing process.
Specific Anomalies Knowledge of the underlying primary diagnosis is critical for safe reoperation. Considerations to specific anatomic issues for specific congenital lesions are outlined below:
Tetralogy of Fallot/Pulmonary Atresia In patients who had prior tetralogy of Fallot or pulmonary atresia with ventricular septal defect (PA/VSD) repair using an extracardiac conduit, the conduit usually lies to
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Figure 9 CT scan with 3-dimensional reconstruction showing: (A) anomalous origin of the LAD from the RCA crossing the right ventricular outflow tract in a patient with tetralogy of Fallot. Corresponding cross sectional image (B) show its close proximity to the sternum. LAD, left anterior descending coronary artery; RCA, right coronary artery; RV, right ventricle; LV, left ventricle. Ao, aorta; PA, pulmonary artery. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
the left of the midline but is often in contact with the left chest wall or left side of the sternum. The aorta may be dilated (as is the case with all conotruncal anomalies) and is typically in the midline and in close proximity to the back of the sternum. Coronary artery distribution/anomalies are not uncommon and determination of the location of major coronary arterial branches (i.e., anomalous left anterior descending from the right coronary artery) is important during reoperation (Fig. 9). Anomalous vessels can be vulnerable during sternal reentry or at the time of any ventricular incisions or dissection of a prior conduit that may be needed for a given procedure.
Truncus Arteriosus/Transposition of the Great Arteries In patients who underwent a previous Rastelli procedure for transposition of the great arteries with pulmonary stenosis, the extracardiac conduit is commonly located in a midline position (particularly if the distal conduit anastomosis was to the right pulmonary artery), and sternal erosion is not uncommon. In patients with simple transposition who underwent an atrial switch procedure (Mustard or Senning), reoperation may be required for atrioventricular valve regurgitation or systemic or pulmonary venous pathway obstruction. Importantly, the morphologic right atrium is the pulmonary venous atrium in this setting. Caution must be exercised to avoid air embolism from inadvertent injury to the right atrium during the course of
dissection with a decompressed heart while on bypass and before aortic cross clamping.
Ross Procedure Reoperation after the Ross procedure is inevitable for many patients; the common indications include the following:
Pulmonary homograft (or RV-PA conduit) structural
degeneration Autograft (neoaorta) valve regurgitation Autograft dilatation Concomitant tricuspid or mitral valve regurgitation Coronary artery abnormalities (usually button or proximal segments)
This group of patients may have aneurysmal dilatation of the proximal aortic root – the pulmonary autograft (neoaorta). It is not uncommon for this proximal dilated segment of aorta to be abutting the sternum (Fig. 10). In addition, the right coronary artery button origin is often high on this dilated proximal segment of aorta and can also be abutting the back of the sternum and be at risk with resternotomy. This emphasizes the importance of cross-sectional imaging in any patient with previous aortic root surgery.
Ebstein Malformation Severe right-sided enlargement (right atrium and ventricle) is the rule with this diagnosis (Fig. 11). A right
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Figure 10 Sagittal view of computed tomography scan (A) and with 3-dimensional reconstruction (B) in a patient with prior Ross procedure. The proximal ascending aorta – the neoaortic root (pulmonary autograft) – is dilated and the abrupt cutoff in the mid-ascending aorta is the location of the distal anastomotic suture line from the autograft to the native ascending aorta. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
ventricular myopathy with right ventricular dysfunction, in addition to tricuspid regurgitation, is always present. Echocardiography plays an important role in analysis of tricuspid valve anatomy and MRI or CT imaging is preferred for right ventricular size and function. Cardiac catheterization is performed selectively to ascertain
Figure 11 CT scan showing a massively dilated right ventricle in relation to the underside of the sternum; this is a common finding in patients with Ebstein malformation with late presentation. The presence of a plane between these two structures is not always clearly defined. Carefully from the sternum using low-energy electrocautery and sharp dissection. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Figure 12 Intraoperative photograph of a combined pulmonary valve replacement and right pulmonary artery stenting. The patient’s head is to the right of the photo. The proximal end of the stent is flared and sutured (arrow) close to the pulmonary bifurcation. The suction catheter is in the left pulmonary artery. The distal aspect of the bovine pericardial roof is seen on the right at the level of the pulmonary confluence.
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Figure 13 (A) Percutaneous treatment of proximal right pulmonary artery stenosis (thin arrow) with severe right ventricle-topulmonary artery conduit valve (wide arrowhead) regurgitation. (B) Cardiac catheterization showing the appropriately placed stent in the proximal right pulmonary artery (thin arrow). (Reprinted from the American Journal of Cardiology, Vol 102, Menon SC, Cetta F, Dearani JA, et al. Hybrid intraoperative pulmonary artery stent placement for congenital heart disease; pp 1737-1741, 2008, with permission from Elsevier.15)
right- and left-sided filling pressures if consideration is being given to applying the bidirectional cavopulmonary anastomosis. Although right-sided pressures are typically low, the walls of the right atrium and right ventricle are usually very thin and vulnerable to tearing during resternotomy, sternal retraction, and mediastinal dissection.
commonly in the left PA (13 stents). The most common diagnoses were PA/VSD and tetralogy of Fallot. This was almost always done with RVOT reconstruction and pulmonary valve replacement. Two procedures were done as rescue procedures following complications (stent migration and catheter impaction) of percutaneous approaches. There was no early mortality or pulmonary artery tear, dissection, or stent thrombosis.
Hybrid Approaches Hybrid strategies are useful in high-risk reoperations and combine the advantages of the open and percutaneous techniques. It serves to decrease CPB time and provide a solution when there are compromised peripheral vascular access issues.
Branch Pulmonary Artery Stenting Branch pulmonary artery stenosis is frequently treated with percutaneous stenting techniques.12 This approach may be challenging in the presence of concomitant right ventricular outflow tract (RVOT) obstruction and, in this situation, the hybrid strategy provides a useful approach (Figs. 12 and 13).13,14 Intraoperative branch PA covered stenting may also be considered as a rescue procedure following complications of the percutaneous approach. We have published our experience with a hybrid strategy in 24 patients between 1997 and 2006.15 Median age was 15 years and a total of 27 stents were deployed, most
Pulmonary Venous Baffle Obstruction Pulmonary venous pathway baffle obstruction is a potential late complication following the atrial switch operation. Treatment of such sequela is very challenging and gaining peripheral access to the pulmonary venous baffle/pathway can be difficult. Only case reports exist in the literature for interventional catheterization approaches to treat pulmonary or systemic venous baffle obstruction.16,17 We reported our experience with this approach in a 28-year-old female who underwent an atrial switch procedure at 11 months of age and presented with late pulmonary venous pathway baffle obstruction.18 Preoperative transthoracic echocardiography revealed a mean gradient of 14 mmHg across the pulmonary venous pathway (Fig. 14). A mini right thoracotomy was performed, a purse string suture was placed on the right atrial free wall, and a sheath was advanced allowing a stent to be deployed. The intraoperative gradient dropped to 4 mmHg after stent deployment. One year
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Other advantages include the avoidance of CPB and the risks associated with repeat sternotomy.
Coronary Artery Disease
Figure 14 Two-dimensional transesophageal echocardiography during a hybrid procedure that demonstrates severe narrowing (0.78 cm) of the pathway between the PVA and the native RA in a patient that had undergone an atrial switch procedure for transposition of the great arteries. PVA, pulmonary venous atrium; RA, right atrium. (Reprinted from Annals of Thoracic Surgery, Vol 88, Sareyyupoglu B, Burkhart HM, Hagler DJ, et al. Hybrid approach to repair of pulmonary venous baffle obstruction after atrial switch operation; pp 1710-1711, 2009, with permission from Wolters Kluwer Health.18)
later, follow-up echocardiography revealed a widely patent stent (Fig. 15). The same technique was repeated in two other patients from our institution with similar success. Several advantages to this technique are worth mentioning. The operation is performed via a small right chest incision with adequate exposure to the right atrial wall. It provides direct access to the area of obstruction, thereby avoiding the difficulty encountered with the percutaneous approaches.
The presence of acquired coronary artery disease can add additional challenges when there have been multiple prior operations because coronary artery anatomy can be obscured. In addition, the presence of significant cardiomegaly can also make coronary artery bypass grafting difficult at reoperation. In general, our strategy is to approach left anterior descending disease with coronary bypass grafting using the left internal thoracic artery. Lesions of the circumflex and right coronary arteries are more often approached with percutaneous stenting prior to resternotomy. Consideration to a percutaneous approach for left anterior descending disease is given when reoperation involves pulmonary valve replacement or right ventricle to pulmonary artery conduit replacement so left internal thoracic artery injury can be avoided at a subsequent operation. An individualized approach with careful analysis and review between interventional cardiology and surgery is essential in these circumstances.
Mayo Clinic Experience with Reoperation in CHD We reviewed our experience with 984 adult patients (495 male) with CHD who underwent reoperation between January 1993 and December 2007.19 Mean age at reoperation was 36.4 years. The most common diagnoses were: conotruncal anomaly, 361 (37%); Ebstein/tricuspid valve, 174 (18%); pulmonary stenosis/RVOT obstruction, 92 (9%); single ventricle, 71 (7%); atrioventricular septal defect, 64 (7%); subaortic stenosis, 62 (6%); aortic arch abnormalities, 23 (2%); and anomalous pulmonary veins, 21 (2%). The overall mortality was 3.6%. Repeat sternotomy with the potential risk of cardiac injury conferred an increased mortality of 6%. The following factors were independent predictors of cardiac injury: single ventricle diagnosis and increased number of prior sternotomies. It was also noticed that with increase time from previous sternotomy, there is a decrease incidence of cardiac injury. Predictors of perioperative mortality included urgency of the operation, single ventricle diagnosis, and longer bypass time.
Summary Figure 15 Two-dimensional transesophageal echocardiography after a hybrid approach and placement of the stent across the stenosis between the PVA and the native RA. Pulmonary venous pathway diameter now equals 1.41 cm after stent deployment. PVA, pulmonary venous atrium; RA, right atrium. (Reprinted from Annals of Thoracic Surgery, Vol 88, Sareyyupoglu B, Burkhart HM, Hagler DJ, et al. Hybrid approach to repair of pulmonary venous baffle obstruction after atrial switch operation; pp 1710-1711, 2009, with permission from Elsevier.18)
Patients with CHD are subject to repeat reoperations and complex procedures. Thoughtful surgical planning and proper preoperative imaging are critical to a safe, successful operation. Specific intraoperative strategies that facilitate the conduct of reoperation can reduce morbidity and mortality.
References 1. Hoffman JI, Kaplan S, Liberthson RR: Prevalence of congenital heart disease. Am Heart J 2004;147:425-439
Strategies for high-risk reoperations in CHD 2. Warnes CA: The adult with congenital heart disease: born to be bad? J Am Coll Cardiol 2005;46:1-8 3. Christenson JT, Schmziger M, Simmat F: Reoperative coronary artery bypass. Risk factors for early mortality and late survival. Eur J Cardiothorac Surg 1997;1:129-133 4. Park CB, Suri RM, Burkhart HM, et al: Identifying patients at particular risk of injury during repeat sternotomy: analysis of 2555 cardiac reoperations. J Thorac Cardiovasc Surg 2010;140:1028-1035 5. Bhat AH, Sahn DJ: Congenital heart disease never goes away, even when it has been ‘treated’: the adult with congenital heart disease. Curr Opin Pediatr 2004;16:500-507 6. Walther T, Rastan A, Dähnert I, et al: A novel adhesion barrier facilitates reoperations in complex congenital cardiac surgery. J Thorac Cardiovasc Surg 2005;129:359-363 7. Kirshbom PM, Myung RJ, Simsic JM, et al: One thousand repeat sternotomies for congenital cardiac surgery: risk factors for reentry injury. Ann Thorac Surg 2009;88:158-161 8. Akl BF, Pert SB, Wernly JA: Use of a sagittal oscillating saw for repeat sternotomy: a safer and simpler technique. Ann Thorac Surg 1984;38: 646-647 9. Rady MY, Ryan T, Starr NJ: Perioperative determinants of morbidity and mortality in elderly patients undergoing cardiac surgery. Crit Care Med 1998;26:225-235 10. Nuttall GA, Oliver WC, Santrach PJ, et al: Efficacy of a simple intraoperative transfusion algorithm for nonerythrocyte component utilization after cardiopulmonary bypass. Anesthesiology 2001;94:773-781
21 11. Romano MA, Haft JW, Pagani FD, et al: Beating heart surgery via right thoracotomy for reoperative mitral valve surgery: a safe and effective operative alternative. J Thorac Cardiovasc Surg 2012;144:334-339 12. Bergersen L, Lock JE: What is the current option of first choice for treatment of pulmonary arterial stenosis? Cardiol Young 2006;16: 329-338 13. Ing FF: Delivery of stents to target lesions: techniques of intraoperative stent implantation and intraoperative angiograms. Pediatr Cardiol 2005; 26:260-266 14. Shaffer KM, Mullins CE, Grifka RG, et al: Intravascular stents in congenital heart disease: short- and long-term results from a large single-center experience. J Am Coll Cardiol 1998;31:661-667 15. Menon SC, Cetta F, Dearani JA, et al: Hybrid intraoperative pulmonary artery stent placement for congenital heart disease. Am J Cardiol 2008; 102:1737-1741 16. Dragulescu A, Sidibe N, Aubert F, et al: Successful use of covered stent to treat superior systemic baffle obstruction and leak after atrial switch procedure. Pediatr Cardiol 2008;29:954-956 17. Ebeid MR, Gaymes CH, McMullan MR, et al: Catheter management of occluded superior baffle after atrial switch procedures for transposition of great vessels. Am J Cardiol 2005;95:782-786 18. Sareyyupoglu B, Burkhart HM, Hagler DJ, et al: Hybrid approach to repair of pulmonary venous baffle obstruction after atrial switch operation. Ann Thorac Surg 2009;88:1710-1711 19. Holst KA, Dearani JA, Burkhart HM, et al: Risk factors and early outcomes of multiple reoperations in adults with congenital heart disease. Ann Thorac Surg 2011;92:122-130
Introduction
I
t is estimated that there are more than one million adults with congenital heart disease (CHD) in the United States alone.1 This is the result of the significant improvement in surgical techniques and perioperative care, with more than 90% of newborns with CHD surviving to adulthood.2 However, despite this improvement, residual or recurrent lesions may progress over years and decades, resulting in the need for reoperation(s). It is expected that the number of adults with CHD will continue to increase as the population increases. In this article, we will review the surgical issues related to redo cardiac surgery in patients with CHD and the different perioperative strategies to decrease the risks associated with reoperation.
Adults with CHD Adults with CHD include the following two groups: the first, which is the majority, includes those who will need reoperation to fix residual or recurrent defects or treat long-term complications (e.g., valve deterioration); and the second group includes those with previously undetected CHD who present for the first time in adulthood. The most common indications
for reoperation(s) are related to valve dysfunction, residual or recurrent intracardiac defects or arrhythmias; patients undergoing reoperation are the focus of this review. Several factors are important and contribute to perioperative mortality and morbidity with repeat cardiac operations. This includes older age, female sex, preoperative renal failure, prior history of stroke, and obesity.3 Additional factors have been identified by Park et al4 included: previous radiation, preoperative heart failure or cardiogenic shock, previous coronary artery bypass grafting, and emergency status. Inadvertent cardiotomy with significant hemorrhage encountered during redo sternotomy increases mortality dramatically to 25% versus 6.5% when there is no injury.
Preoperative Evaluation Echocardiography Echocardiography is mandatory for determining accurate diagnosis, details about valve anatomy, and ventricular function. The following are specific data pertinent to resternotomy:
Evaluating ventricular function as decreased myocardial
a
Instructor of Surgery, Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN. b Professor of Surgery, Chair, Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN. Address correspondence to Joseph A. Dearani, MD, Division of Cardiovascular Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN, USA. 55905. E-mail: [email protected]
http://dx.doi.org/10.1053/j.pcsu.2014.01.004 1092-9126/& 2014 Elsevier Inc. All rights reserved.
function has been an independent risk factor of early mortality and overall outcome.5 The presence of an intracardiac shunt or residual septal defect (atrial or ventricular level) increases the risk of air embolism if inadvertent cardiotomy occurs while the heart is fully decompressed on cardiopulmonary bypass (CPB) at resternotomy. Identifying the presence of aortic regurgitation is particularly important. When aortic regurgitation is present, 9
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Figure 1 Preoperative cross-sectional images demonstrating the relationship of the mediastinal structures to the underside of the sternum. In this particular case the ascending aorta (A) and the aortic arch (B) are eroding into the sternum. Knowledge of this preoperatively is essential when planning redo sternotomy. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
venting of the left ventricle after initiation of bypass is critical in the event that ventricular fibrillation occurs (which is expected with hypothermic bypass) to avoid subendocardial ischemia from left ventricular distension. Intraoperative transesophageal echocardiography provides guidance for peripheral cannulation and ensures proper positioning of cannulae; it helps in evaluating collapse of the cardiac chambers after initiation of peripheral CPB, provides a continuous evaluation of the contractile status and distension of the ventricle(s), and provides continuous information about intracardiac air.
preferred to CT imaging when serial studies are required over an extended period of time.
Cardiac Catheterization Cardiac catheterization is applied selectively and is most important for hemodynamic assessment (pressure measurements, vascular resistance, etc.). Knowledge of coronary artery anatomy and the presence of acquired coronary lesions
Computed Tomography (CT) Scan The relationship of cardiac structures (chambers and great vessels) to each other and to the chest wall is essential when planning reoperation. Anatomic landmarks, especially coronary arteries may be obscured, and an extracardiac conduit or dilated ascending aorta may become very close or adherent to the undersurface of the sternum or chest wall (Fig. 1). In advanced cases, preoperative imaging of these anatomic structures has demonstrated erosion into the sternum, and this significantly increases the risk of resternotomy. The recent introduction of 3-dimensional reconstructions also provides the surgeon with an anatomic model of the heart and mediastinal structures, and facilitates operative planning (Fig. 2). Magnetic Resonance Imaging (MRI) MRI provides excellent cross-sectional imaging, similar to CT scanning, and it is particularly helpful at providing additional information about cardiac chamber size and ventricular function (especially the right ventricular size and function, which is more difficult to evaluate by echocardiography). MRI has the advantage of no radiation and for this reason may be
Figure 2 CT scan with 3-D reconstruction demonstrating a dilated ascending aorta (AA) above the sinotubular junction, location of the major coronary arteries in relation to the sternum, and the presence of calcification in the aortic arch (white arrows), and to a lesser degree in the ascending and descending aorta (white patches). AA, ascending aorta; RCA, right coronary artery. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
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are critical when planning resternotomy and the potential need for coronary bypass grafting. Peripheral Access evaluation Adults with CHD have often had multiple prior invasive diagnostic and/or therapeutic procedures that result in scarring, stenosis, and obstruction of peripheral arterial and venous structures in the neck and/or the groin. Knowledge of patency of peripheral vasculature is critical because peripheral cannulation for CPB becomes a strategic alternative during a hazardous resternotomy. This can be done using ultrasound or other cross-sectional imaging studies. The following alternative cannulation sites may be considered if there is a high risk of cardiac injury at resternotomy: ■ ■ ■ ■ ■ ■ ■ ■
Femoral artery or vein vessels Iliac artery or vein vessels Axillary artery Internal jugular vein (usually right) Right atrium or ascending aorta (via right thoracotomy) Left ventricular apex (via left thoracotomy) Pulmonary artery (via left thoracotomy) Abdominal aorta
Timing of Resternotomy The time period since last sternotomy plays an important role in the degree and quality of mediastinal adhesions. Reoperation in the first 6 to 12 months has been associated with worse outcome because of vascularity and immaturity of adhesions, which causes mediastinal dissection to be more difficult. In general, the greater the time period between the reoperation from the previous operation, the less dense and less vascular the adhesions, which can minimize bleeding and its related morbidities. In addition to factors related to the duration between operations, it is important to advise reoperation before the onset of significant ventricular dysfunction. This is particularly important when there are regurgitant valve lesions that result in progressive ventricular dilatation and dysfunction. Timely referral to surgery before the onset of significant ventricular dysfunction can also help reduce perioperative morbidity and mortality.
Surgical Technique of Resternotomy Accurate preoperative assessment and communication with other team members, including the cardiologist, anesthesiologist, perfusionist, and operating room team, is an important element to success with reoperation. Our strategy includes:
If there is a high risk of injury to the heart or great vessels with resternotomy, peripheral cannulation of femoral or axillary vessels is preferred. This is determined by preoperative evaluation of cross-sectional imaging and the close relationship of these structures to the posterior
sternum. Although percutaneous techniques facilitate right internal jugular and groin cannulation with almost no need for an incision in the case of emergency (Fig. 3), we prefer cutdown exposure of groin vessels so that repair can be accomplished under direct vision at the time of cannula removal. Additional venous return can be achieved with a percutaneous cannula advanced into the right superior vena cava from the right internal jugular vein before resternotomy; this is also helpful if bicaval cannulation is going to be required for the planned procedure. Selective use of vacuum-assisted venous drainage is helpful; however, it should be avoided or used with extreme caution in the presence of residual intracardiac shunts to minimize the risk of air embolism, especially if there is injury to a right-sided cardiac chamber during resternotomy. In this situation, it is essential to avoid vacuum-assist and maintain a positive central venous pressure of 46 to 8 mmHg to avoid air entry into a decompressed right heart and subsequent paradoxical embolism across the shunt. Other measures to minimize the risk of air embolism include: routine use of an aortic root vent (after sufficient mediastinal dissection is complete), Trendelenburg position, and flooding the operative field with carbon dioxide. If the aorta, pulmonary venous atrium, or other left-sided structure is injured, then CPB and deep hypothermia with possible circulatory arrest may become necessary to facilitate safe resternotomy. Based on the relationship between the heart and great vessels to the back of the sternum, initiation of CPB may be considered prior to resternotomy (Fig. 4). This does not necessarily protect the right ventricle from injury; however, it has several advantages: it provides decompression of the right heart, creates a more controllable hemodynamic situation, minimizes the amount of blood loss if injury occurs, and can facilitate mediastinal dissection. This is particularly helpful when there is significant right heart enlargement or elevated right-sided intracardiac pressures. If bypass is initiated before resternotomy to facilitate safe reentry, a decision then needs to be made as to whether bypass can be safely discontinued after resternotomy to allow mediastinal dissection. This reduces a more prolonged bypass time that can contribute to additional morbidity and mortality. Alternatively, in some situations, maintenance and continuation of bypass may further facilitate mediastinal dissection. The use of pericardial substitutes has been controversial6,7; we have a low threshold to use Gore-Tex pericardial membrane if additional reoperation(s) are expected in the future. A previous report from our institution identified that the incidence of injury is reduced if the native pericardium was approximated during the prior surgical procedure.4 We have found the use of biological substitutes to be more challenging with greater scar tissue and adhesions at a subsequent operation.
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Figure 3 Intraoperative photographs showing the cutdown technique of femoral cannulation in preparation for cardiopulmonary bypass prior to redo sternotomy. (A) Small oblique groin incision is performed to expose the femoral vessels and Seldinger technique using a guidewire is performed with purse string sutures on each of the vessels. (B) The puncture site is then dilated over the guidewire before insertion of the cannula. (C) The femoral arterial and (D) femoral venous cannulae are inserted and secured in place with the final position of the venous cannula confirmed using intraoperative transesophageal echocardiography. When the femoral artery is noted to be small and the femoral arterial cannula would result is occlusion of the femoral artery distally, a chimney graft is sewn end-to-side to the femoral artery so antegrade perfusion of the distal leg is preserved. One or both groins can be cannulated based on vascular anatomy. Frequent postoperative examination of distal pulses and extremity perfusion are essential to identify potential compartment syndrome. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Controversy exists regarding the need to remove or retain
the previously placed sternal wires during the actual sawing of the sternum (Fig. 5A). There is no conclusive evidence that cardiac injury is decreased with keeping them intact; the decision is generally based on surgeon preference. Sternal redivision options include a pneumatic microsagittal saw (Fig. 5A) to completely divide entire sternum, or just divide the anterior sternal table followed by careful division of the posterior table with a heavy scissors under direct vision. The use of Volkmann retractors can facilitate elevation of the lower two halves
of the sternum (Fig. 5B). The microsagittal saw has the advantage of precise perpendicular division of the sternum, with relatively easy control of the depth of blade penetration and the ability to feel the posterior sternal table.8 The heart and great vessels should be gently released in a stepwise fashion from the back of the sternum (beginning inferiorly) with a combination of sharp scissors dissection and low-energy electrocautery to allow safe separation of the two sternal halves and release of mediastinal structures from the chest wall. We intentionally enter each pleural
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Figure 4 Preoperative cross-sectional imaging with 3-dimensional reconstruction demonstrating (A) a proximal right coronary artery aneurysm; (B, C) The same patient also has a severe pectus deformity with the mediastinal structures displaced into the left hemithorax; (D) 3-dimensional reformat showing the relationship of the leftward position of the right coronary artery aneurysm to the sternum. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
space to allow a complete release of mediastinal structures and reduce tension on the innominate vein. This allows safe placement and spreading of the sternal retractor (Fig. 5C). A valuable alternative that is now our preferred technique is the use of the craniotome (Midas Rex Microsaw; Medtronic, Minneapolis, MN) to perform resternotomy (Fig. 6). This requires removal of all wires prior to division. Some degree of dissection at both the superior or inferior aspect of the sternum is required before engaging the microsaw under the sternum (Fig. 7). The ergonomically designed handpiece facilitates easy and precise control of the saw, and the thin
rotating blade with the protective distal flange minimizes the risk of injury to mediastinal structures. We have not encountered a single cardiac injury from this saw with sternal re-entry using this technique. It is important to be cautious with cephalad retraction of the successfully divided sternum during takedown of adhesions to avoid a “retraction tear” of the right atrium or right ventricle. Limiting dissection only to the necessary areas of the intended procedure is an important consideration as it decreases the risk of injury to cardiac structures, and results in less bleeding from dissected areas at the end of the procedure.
14
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Figure 5 Intraoperative photos demonstrating our technique of resternotomy when using a microsagittal saw. (A) The microsagittal saw is helpful during redo sternotomy because of its ease of handling. (B) Rake retractors are placed at the level of the xiphoid and towel clips are used on either side of the sternum to elevate the corresponding half during the resternotomy. (C) In general, we use the saw for division of the anterior sternal table and heavy blunt scissors to divide the posterior table with the help of Volkmann retractors to elevate the sternum so the posterior table is divided under direct vision. After dividing the posterior sternal table, the mediastinal structures are dissected and released redivision. The rotating blade is small (wide arrow) and is protected from the heart by the flanged lip distally, which allows precise and safe redivision of the sternum. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Figure 6 (A and B) Intraoperative photos showing the alternative use of the craniotome (Midas Rex Microsaw), which is our current preferred technique of sternal division.
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Figure 7 Intraoperative photos showing the technique of sternal division using the craniotome: (A) the sternal wires have to be removed, and the either the superior edge of the sternum (B), or the subxiphoid end (C) can be used to engage the craniotome. The smaller blade allows precise control and minimizes injury to surrounding mediastinal structures during resternotomy.
Strategies for Safe Peripheral Cannulation Peripheral cannulation represents an important strategy to facilitate sternal redivision and reduce the incidence of injury to cardiac and/or other mediastinal structures during complex resternotomy. Several sites have been suggested as previously mentioned; however, concerns related to peripheral cannulation (especially lower extremity vessels) include leg ischemia, compartment syndrome, or retrograde dissection from femoral artery cannulation. The following represents our current strategy to minimize morbidity related to peripheral cannulation:
Proper preoperative evaluation of peripheral vessels using
ultrasonography or cross-sectional imaging, especially with multiple prior reoperations or groin interventions that increases the chance of encountering difficulty during repeat groin vessel cannulation. We tend to prefer the right groin for cannulation. It is important to emphasize that the ideal peripheral cannulation allows antegrade perfusion of the instrumented lower extremity and satisfactory venous return of
that same extremity. This requires not oversizing the femoral venous cannula that would result in femoral venous obstruction. Antegrade perfusion of the leg with inadequate femoral venous outflow can result in compartment syndrome. Compartment syndrome can also result from an oversized femoral arterial cannula that causes obstruction and inadequate distal femoral artery perfusion. Consideration to utilizing both groins for arterial and venous cannulation may minimize extremity complications. Once adequate mediastinal dissection is accomplished, conversion to central cannulation should be performed to minimize or avoid extremity complications. If the femoral artery is small, the use of Chimney graft is helpful to ensure bidirectional flow in the femoral artery up and down the lower extremity to avoid leg ischemia. Use of the axillary artery with a chimney graft represents a safe alternate cannulation site. Several advantages for axillary artery over femoral artery cannulation exist: (1) it provides antegrade flow that is associated with lower stroke rate and of value in those with diseased and atherosclerotic aorta; (2) the axillary artery is usually free
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Figure 8 Our current coagulation test-based intraoperative transfusion protocol that served to minimize transfusion requirements significantly.
of atheroma, which makes it an ideal site for cannulation; (3) facilitates selective antegrade cerebral perfusion during aortic arch surgery; and (4) the use of a side arm graft has decreased the morbidity associated with direct axillary artery cannulation. Early conversion to central cannulation should be the rule to minimize morbidity related to peripheral cannulation because of the size of peripheral vessels or the duration of the CPB.
Blood Transfusion Algorithm Transfusion of blood and/or blood products has been an independent risk factor associated with increased morbidity and mortality after cardiac surgery.9 This becomes critically important because abnormal bleeding is common with complex reoperations because of the extensive mediastinal adhesions and dissection, and potentially long bypass times that result in associated coagulation abnormalities. The decision to transfuse and which product required is often difficult under these circumstances and treatment most of the time is empirical. In an effort to minimize transfusions of blood and its related products and the associated risks, we developed a coagulation test-based transfusion algorithm that is based on a large prospective randomized study in over 800 patients (Fig. 8). This has demonstrated a significant reduction in allogenic RBC, platelet, and fresh frozen plasma transfusions compared with the control group.10
Right Thoracotomy for Reoperation Right thoracotomy can be a useful alternative to a high-risk resternotomy and it is applicable for approaches to the mitral and/or the tricuspid valves. It avoids major hemorrhagic complications of resternotomy, including inadvertent cardiotomy, or injury to previous patent bypass grafts, extracardiac conduits, or the aorta. This can be performed using aortic occlusion and cardioplegic arrest, fibrillatory arrest, or the beating heart techniques depending upon the procedure. Additional advantages include minimal mediastinal dissection, which may further decrease CPB time and transfusion requirements.11 Limitations with this approach can include scarring from prior right thoracotomy, large body habitus or obesity, control of the aorta and application of the cross clamp, and the de-airing process.
Specific Anomalies Knowledge of the underlying primary diagnosis is critical for safe reoperation. Considerations to specific anatomic issues for specific congenital lesions are outlined below:
Tetralogy of Fallot/Pulmonary Atresia In patients who had prior tetralogy of Fallot or pulmonary atresia with ventricular septal defect (PA/VSD) repair using an extracardiac conduit, the conduit usually lies to
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Figure 9 CT scan with 3-dimensional reconstruction showing: (A) anomalous origin of the LAD from the RCA crossing the right ventricular outflow tract in a patient with tetralogy of Fallot. Corresponding cross sectional image (B) show its close proximity to the sternum. LAD, left anterior descending coronary artery; RCA, right coronary artery; RV, right ventricle; LV, left ventricle. Ao, aorta; PA, pulmonary artery. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
the left of the midline but is often in contact with the left chest wall or left side of the sternum. The aorta may be dilated (as is the case with all conotruncal anomalies) and is typically in the midline and in close proximity to the back of the sternum. Coronary artery distribution/anomalies are not uncommon and determination of the location of major coronary arterial branches (i.e., anomalous left anterior descending from the right coronary artery) is important during reoperation (Fig. 9). Anomalous vessels can be vulnerable during sternal reentry or at the time of any ventricular incisions or dissection of a prior conduit that may be needed for a given procedure.
Truncus Arteriosus/Transposition of the Great Arteries In patients who underwent a previous Rastelli procedure for transposition of the great arteries with pulmonary stenosis, the extracardiac conduit is commonly located in a midline position (particularly if the distal conduit anastomosis was to the right pulmonary artery), and sternal erosion is not uncommon. In patients with simple transposition who underwent an atrial switch procedure (Mustard or Senning), reoperation may be required for atrioventricular valve regurgitation or systemic or pulmonary venous pathway obstruction. Importantly, the morphologic right atrium is the pulmonary venous atrium in this setting. Caution must be exercised to avoid air embolism from inadvertent injury to the right atrium during the course of
dissection with a decompressed heart while on bypass and before aortic cross clamping.
Ross Procedure Reoperation after the Ross procedure is inevitable for many patients; the common indications include the following:
Pulmonary homograft (or RV-PA conduit) structural
degeneration Autograft (neoaorta) valve regurgitation Autograft dilatation Concomitant tricuspid or mitral valve regurgitation Coronary artery abnormalities (usually button or proximal segments)
This group of patients may have aneurysmal dilatation of the proximal aortic root – the pulmonary autograft (neoaorta). It is not uncommon for this proximal dilated segment of aorta to be abutting the sternum (Fig. 10). In addition, the right coronary artery button origin is often high on this dilated proximal segment of aorta and can also be abutting the back of the sternum and be at risk with resternotomy. This emphasizes the importance of cross-sectional imaging in any patient with previous aortic root surgery.
Ebstein Malformation Severe right-sided enlargement (right atrium and ventricle) is the rule with this diagnosis (Fig. 11). A right
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Figure 10 Sagittal view of computed tomography scan (A) and with 3-dimensional reconstruction (B) in a patient with prior Ross procedure. The proximal ascending aorta – the neoaortic root (pulmonary autograft) – is dilated and the abrupt cutoff in the mid-ascending aorta is the location of the distal anastomotic suture line from the autograft to the native ascending aorta. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
ventricular myopathy with right ventricular dysfunction, in addition to tricuspid regurgitation, is always present. Echocardiography plays an important role in analysis of tricuspid valve anatomy and MRI or CT imaging is preferred for right ventricular size and function. Cardiac catheterization is performed selectively to ascertain
Figure 11 CT scan showing a massively dilated right ventricle in relation to the underside of the sternum; this is a common finding in patients with Ebstein malformation with late presentation. The presence of a plane between these two structures is not always clearly defined. Carefully from the sternum using low-energy electrocautery and sharp dissection. (Reprinted from Cardiac CT and MRI for Adult Congenital Heart Disease; Farhood S, editor; pp 431-449, 2013, with permission from Springer.)
Figure 12 Intraoperative photograph of a combined pulmonary valve replacement and right pulmonary artery stenting. The patient’s head is to the right of the photo. The proximal end of the stent is flared and sutured (arrow) close to the pulmonary bifurcation. The suction catheter is in the left pulmonary artery. The distal aspect of the bovine pericardial roof is seen on the right at the level of the pulmonary confluence.
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Figure 13 (A) Percutaneous treatment of proximal right pulmonary artery stenosis (thin arrow) with severe right ventricle-topulmonary artery conduit valve (wide arrowhead) regurgitation. (B) Cardiac catheterization showing the appropriately placed stent in the proximal right pulmonary artery (thin arrow). (Reprinted from the American Journal of Cardiology, Vol 102, Menon SC, Cetta F, Dearani JA, et al. Hybrid intraoperative pulmonary artery stent placement for congenital heart disease; pp 1737-1741, 2008, with permission from Elsevier.15)
right- and left-sided filling pressures if consideration is being given to applying the bidirectional cavopulmonary anastomosis. Although right-sided pressures are typically low, the walls of the right atrium and right ventricle are usually very thin and vulnerable to tearing during resternotomy, sternal retraction, and mediastinal dissection.
commonly in the left PA (13 stents). The most common diagnoses were PA/VSD and tetralogy of Fallot. This was almost always done with RVOT reconstruction and pulmonary valve replacement. Two procedures were done as rescue procedures following complications (stent migration and catheter impaction) of percutaneous approaches. There was no early mortality or pulmonary artery tear, dissection, or stent thrombosis.
Hybrid Approaches Hybrid strategies are useful in high-risk reoperations and combine the advantages of the open and percutaneous techniques. It serves to decrease CPB time and provide a solution when there are compromised peripheral vascular access issues.
Branch Pulmonary Artery Stenting Branch pulmonary artery stenosis is frequently treated with percutaneous stenting techniques.12 This approach may be challenging in the presence of concomitant right ventricular outflow tract (RVOT) obstruction and, in this situation, the hybrid strategy provides a useful approach (Figs. 12 and 13).13,14 Intraoperative branch PA covered stenting may also be considered as a rescue procedure following complications of the percutaneous approach. We have published our experience with a hybrid strategy in 24 patients between 1997 and 2006.15 Median age was 15 years and a total of 27 stents were deployed, most
Pulmonary Venous Baffle Obstruction Pulmonary venous pathway baffle obstruction is a potential late complication following the atrial switch operation. Treatment of such sequela is very challenging and gaining peripheral access to the pulmonary venous baffle/pathway can be difficult. Only case reports exist in the literature for interventional catheterization approaches to treat pulmonary or systemic venous baffle obstruction.16,17 We reported our experience with this approach in a 28-year-old female who underwent an atrial switch procedure at 11 months of age and presented with late pulmonary venous pathway baffle obstruction.18 Preoperative transthoracic echocardiography revealed a mean gradient of 14 mmHg across the pulmonary venous pathway (Fig. 14). A mini right thoracotomy was performed, a purse string suture was placed on the right atrial free wall, and a sheath was advanced allowing a stent to be deployed. The intraoperative gradient dropped to 4 mmHg after stent deployment. One year
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Other advantages include the avoidance of CPB and the risks associated with repeat sternotomy.
Coronary Artery Disease
Figure 14 Two-dimensional transesophageal echocardiography during a hybrid procedure that demonstrates severe narrowing (0.78 cm) of the pathway between the PVA and the native RA in a patient that had undergone an atrial switch procedure for transposition of the great arteries. PVA, pulmonary venous atrium; RA, right atrium. (Reprinted from Annals of Thoracic Surgery, Vol 88, Sareyyupoglu B, Burkhart HM, Hagler DJ, et al. Hybrid approach to repair of pulmonary venous baffle obstruction after atrial switch operation; pp 1710-1711, 2009, with permission from Wolters Kluwer Health.18)
later, follow-up echocardiography revealed a widely patent stent (Fig. 15). The same technique was repeated in two other patients from our institution with similar success. Several advantages to this technique are worth mentioning. The operation is performed via a small right chest incision with adequate exposure to the right atrial wall. It provides direct access to the area of obstruction, thereby avoiding the difficulty encountered with the percutaneous approaches.
The presence of acquired coronary artery disease can add additional challenges when there have been multiple prior operations because coronary artery anatomy can be obscured. In addition, the presence of significant cardiomegaly can also make coronary artery bypass grafting difficult at reoperation. In general, our strategy is to approach left anterior descending disease with coronary bypass grafting using the left internal thoracic artery. Lesions of the circumflex and right coronary arteries are more often approached with percutaneous stenting prior to resternotomy. Consideration to a percutaneous approach for left anterior descending disease is given when reoperation involves pulmonary valve replacement or right ventricle to pulmonary artery conduit replacement so left internal thoracic artery injury can be avoided at a subsequent operation. An individualized approach with careful analysis and review between interventional cardiology and surgery is essential in these circumstances.
Mayo Clinic Experience with Reoperation in CHD We reviewed our experience with 984 adult patients (495 male) with CHD who underwent reoperation between January 1993 and December 2007.19 Mean age at reoperation was 36.4 years. The most common diagnoses were: conotruncal anomaly, 361 (37%); Ebstein/tricuspid valve, 174 (18%); pulmonary stenosis/RVOT obstruction, 92 (9%); single ventricle, 71 (7%); atrioventricular septal defect, 64 (7%); subaortic stenosis, 62 (6%); aortic arch abnormalities, 23 (2%); and anomalous pulmonary veins, 21 (2%). The overall mortality was 3.6%. Repeat sternotomy with the potential risk of cardiac injury conferred an increased mortality of 6%. The following factors were independent predictors of cardiac injury: single ventricle diagnosis and increased number of prior sternotomies. It was also noticed that with increase time from previous sternotomy, there is a decrease incidence of cardiac injury. Predictors of perioperative mortality included urgency of the operation, single ventricle diagnosis, and longer bypass time.
Summary Figure 15 Two-dimensional transesophageal echocardiography after a hybrid approach and placement of the stent across the stenosis between the PVA and the native RA. Pulmonary venous pathway diameter now equals 1.41 cm after stent deployment. PVA, pulmonary venous atrium; RA, right atrium. (Reprinted from Annals of Thoracic Surgery, Vol 88, Sareyyupoglu B, Burkhart HM, Hagler DJ, et al. Hybrid approach to repair of pulmonary venous baffle obstruction after atrial switch operation; pp 1710-1711, 2009, with permission from Elsevier.18)
Patients with CHD are subject to repeat reoperations and complex procedures. Thoughtful surgical planning and proper preoperative imaging are critical to a safe, successful operation. Specific intraoperative strategies that facilitate the conduct of reoperation can reduce morbidity and mortality.
References 1. Hoffman JI, Kaplan S, Liberthson RR: Prevalence of congenital heart disease. Am Heart J 2004;147:425-439
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