CASE REPORT

Anesthetic Management of Total Tetralogy of Fallot Repair in an Adult Patient after Diagnosis by Transesophageal EchocardiographyDutt And Ngai Michael Dutt, MD and Jennie Ngai, MD

D

ESPITE ITS RELATIVELY HIGH prevalence during childhood, unrepaired tetralogy of Fallot (TOF) in adult patients rarely is encountered by anesthesiologists. Survival to adulthood without repair often is possible only when the structural defects present are mild enough to allow for adequate pulmonary circulation and cardiac output.1 These patients eventually become unable to compensate for continued obstruction of the right ventricular outflow tract (RVOT) and shunting through ventricular septal defects (VSD).2 They most commonly present with dyspnea on exertion, chest pain, and palpitations related to right ventricular failure and other associated anatomic anomalies. Below, the authors describe the intraoperative diagnosis and management of TOF in a 55-year-old patient who was scheduled to undergo aortic valve replacement for aortic regurgitation and stenosis that had been diagnosed previously by transthoracic echocardiography (TTE). A discussion of the utility of transesophageal echocardiography (TEE) in diagnosing TOF and the potentially critical implications involved with providing anesthesia to these patients follows. CASE REPORT A 55-year-old female with a history of hypertension and obesity (body mass index of 33) presented with several months of general fatigue and exertional dyspnea. She stated that she would become short of breath after walking 5 blocks or 1 flight of stairs and that this dyspnea was associated with generalized chest pressure and discomfort. A preoperative TTE showed severe aortic stenosis and regurgitation and a dilated ascending aorta. She was scheduled for an aortic valve replacement. TEE was performed after an uneventful induction of general anesthesia and intubation. This examination revealed the additional finding of a perimembranous VSD that was 2-3 cm in diameter with left-to-right shunt and prolapse of the right coronary cusp of the aortic valve into the flow of the VSD (Figs 1 and 2). The flow through the VSD was limited partially by the right coronary cusp, which was covering most of its area. Figure 3 shows the severe aortic regurgitation resulting from the right coronary cusp prolapse. The aorta was noted to override both the left and right ventricles (Fig 4). In addition, a subaortic membrane was seen protruding from the interventricular septum causing obstruction of the left ventricular outflow tract (LVOT). Moderate infundibular hypertrophy, subvalvular obstruction of the RVOT and right ventricular hypertrophy (RVH) also were observed (Fig 5). The aortic valve replacement was cancelled and she was rescheduled for surgical repair of her newly diagnosed TOF after consultation with the congenital cardiothoracic surgery team. The patient returned to the operating room, and general anesthesia was induced with sufentanil, etomidate, and vecuronium and maintained with isoflurane while preventing decreases in mean arterial pressure below 60 mmHg. She was placed on cardiopulmonary bypass and both the subaortic membrane and right ventricular infundibular muscle were resected. Next, the VSD was closed with a Gore-Tex

patch. The right coronary cusp of the aortic valve was noted to be thin and extremely elongated while the left and noncoronary cusps were severely calcified and rigid. Therefore, the decision was made to replace the aortic valve. Finally, a subpulmonary RVOT patch was placed. The patient was weaned from cardiopulmonary bypass with stable hemodyamics on milrinone, epinephrine, and phenylephrine infusions. Postbypass TEE showed good contractility with inotropic support and absence of aortic insufficiency, VSD, or residual LVOT or RVOT obstruction. Right and left ventricular dilation and hypertrophy persisted after repair. The patient was extubated the following day and weaned from all pressors and inotropes. Postoperative electrocardiograph revealed widened QRS complexes and occasional ventricular ectopy. The electrophysiology study showed no inducible ventricular arrhythmias and the patient was discharged home on postoperative day 13. DISCUSSION

Tetralogy of Fallot is the most common cyanotic congenital heart defect diagnosed after infancy; however, it is rarely diagnosed in adulthood because of the low rate of survival without surgical repair.3 Without surgery, the expected survival rate is 66% at age 1, 40% at age 3, 11% at age 20, 6% at age 30, and 3% at age 40.4 Currently, the Centers for Disease Control estimates that 1 in 2,518 children in the United States are born with TOF.5 Therefore, the likelihood of one of these children surviving to age 40 is approximately 0.0012%. The classic findings in TOF are the presence of an aorta that overrides the right and left ventricles, a VSD, RVOT obstruction, and RVH. These structural abnormalities usually can be diagnosed by TTE. The aortic override in TOF is often the result of an aortic valve that is positioned more anterior, superior, and to the right than usual.6 The VSD usually is large and diminishes the pressure gradient between the left and right ventricles. Flow through the VSD can be left-to-right, right-to-left, or bidirectional and depends on the severity of the RVOT obstruction, which can be the result of narrowing of the

From the Department of Anesthesiology, New York University Langone Medical Center, New York, NY. Address reprint requests to Jennie Ngai, MD, New York University Langone Medical Center, Department of Anesthesiology, 550 First Avenue, 530 TH, New York, NY 10016. E-mail: Jennie.Ngai@nyumc. org © 2014 Elsevier Inc. All rights reserved. 1053-0770/2602-0033$36.00/0 http://dx.doi.org/10.1053/j.jvca.2013.11.015 Key words: tetralogy of Fallot, transthoracic echocardiography, transesophageal echocardiography, anesthesia, anesthetic management

Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), 2014: pp ]]]–]]]

1

2

ANESTHETIC MANAGEMENT OF FALLOT REPAIR

Fig 1. Mid-esophageal aortic valve long-axis view showing prolapse of the right coronary cusp of the aortic valve into the flow of the VSD. A subaortic membrane is seen coming off of the interventricular septum and obstructing the LVOT.

subpulmonary infundibulum, stenosis of the pulmonary valve, or both. When the obstruction is secondary to a stenotic valve then its severity is unlikely to be variable. However, RVOT obstruction secondary to decreased size of the subpulmonary infundibulum can be dynamic and exacerbated by hypovolemia, tachycardia, and increased inotropy. In infants with the classic presentation of the disease,

Fig 2.

cyanosis results from the right-to-left shunt through the VSD. The cyanotic episodes, or tet spells, are exacerbated mainly by a decrease in systemic vascular resistance causing flow through the VSD to become right-to-left since the flow across the RVOT is normally relatively fixed. RVH in TOF results from increased pressure transmitted from the RVOT obstruction.

Mid-esophageal aortic valve short-axis view. The aberrant motion of the right coronary cusp during systole is clearly seen.

ANESTHETIC MANAGEMENT OF TOTAL TETRALOGY OF FALLOT REPAIR IN AN ADULT PATIENT AFTER DIAGNOSIS BY TRANSESOPHAGEAL ECHOCARDIOGRAPHYDUTT AND NGAI 3

Fig 3.

Mid-esophageal aortic valve long-axis view with aortic regurgitation seen on color Doppler.

Important anatomic and physiologic differences in adults with TOF exist that allow for their increased survival time without surgery and less severe clinical manifestations. These patients usually have less severe RVOT obstruction and less right-to-left shunt. This RVOT obstruction is often valvular in nature and associated with a short or wide infundibulum. Cyanotic episodes during infancy are not observed in these patients. The most common symptom experienced by this population is dyspnea on exertion, which is how the authors’

Fig 4.

patient presented. Palpitations, chest pain, and orthopnea also occur on occasion. Patients are more likely to become symptomatic after the age of 50 because the right ventricle becomes less able to tolerate the pressure transmitted from the RVOT obstruction and the volume overload caused by left-to-right shunt. The age-related decrease in left ventricular distensibilty seen in patients with coronary artery disease or hypertension also may contribute to the development of symptoms. Despite the relatively benign natural history of the disease in these adult

Aorta overriding the left and right ventricles.

4

ANESTHETIC MANAGEMENT OF FALLOT REPAIR

Fig 5.

RVOT obstruction secondary to narrowing of the subpulmonary infundibulum and RVH.

patients, long-term subclinical cyanosis can cause conditions that complicate care, such as polycythemia, coagulation defects, development of collaterals to pulmonary circulation, and myocardial dysfunction.7 For example, patients who have developed small subpleural and hilar collateral vessels in response to cyanosis and poor pulmonary blood flow may experience hemoptysis.8 In 1 study of adults who underwent surgical correction of TOF, hemoptysis was a significant preoperative complication in 10 of 100 patients.7 John et al found that 50% of patients who underwent TOF repair at an age greater than 14 years had polycythemia with a hematocrit greater than 60.9 These patients were significantly more prone to postoperative complications, such as pulmonary emboli. Important preoperative evaluation includes an assessment of exercise tolerance and frequency of cyanotic episodes. Laboratory analysis may identify polycythemia or coagulation defects. Severely polycythemic patients can be managed with lower flow rates and cooler perfusate temperatures when on cardiopulmonary bypass. Preoperative cardiac catheterization is useful for demonstrating the magnitude of the shunt through the VSD, the severity of the RVOT obstruction, and the anatomy of the RVOT and pulmonary arteries. Intraoperative management depends on variations in TOF anatomy and physiology. In patients with severe RVOT obstruction and right-to-left shunt, the avoidance of large decreases in mean arterial pressure is critical to prevent worsening cyanosis. The severity of right-to-left shunt theoretically can be attenuated with beta-blockade in patients with a dynamic RVOT obstruction by decreasing infundibular spasm; however, this is not possible with a fixed, valvular RVOT obstruction. Similarly, avoiding tachycardia, hypovolemia, and high inotropic states can relieve dynamic RVOT obstruction. Corrective surgical repair in adults with TOF consists of patch or suture closure of the VSD and relief of the RVOT

obstruction.10 When possible, the VSD is approached by a transatrial incision because life-threatening ventricular arrhythmias are more common with the transventricular approach.11 Expansion of the RVOT is often accomplished by resection of infundibular muscle and placement of a transannular patch, which enlarges the outflow from the right ventricle to the pulmonary arteries. Placement of a transannular patch is known to result in an increased frequency of pulmonary regurgitation, which is often well tolerated initially because of right ventricular dilation, but eventually right ventricular dysfunction may occur, requiring repair or replacement of the pulmonary valve.12 Patients with severe RVH at the time of TOF repair are unlikely to tolerate pulmonary regurgitation. If the valve is not repaired in this scenario, right ventricular failure, arrhythmias, and sudden death are possible. Jost et al reported outcomes of 52 adults over the age of 40 who underwent TOF repair and found that severe pulmonary regurgitation was the most likely indication for reoperation (4 of 49 patients who survived initial repair).10 However, delayed pulmonary valve replacement that is performed after the initial TOF repair has not been shown to decrease the incidence of ventricular tachycardia or sudden death.13 Strategies to spare the pulmonary valve include valve commissurotomy, supravalvar pulmonary artery patching, and subvalvar infundibular patching.14 Pulmonary valve-sparing techniques are more successful when the pulmonary annulus size is adequate. Another option is to replace the pulmonary valve at the time of initial repair. This may be the most suitable option for patients in whom a pulmonary valve-sparing technique is not possible. Pulmonary stenosis or regurgitation is relatively uncommon in adults, who have milder forms of TOF.15 The mortality of TOF repair has been shown to be between 2.5% and 8.5% in adults compared to less than 3% in children.15 Mortality is approximately 0% when surgery is performed at less than 12 months of age and 4.4% when

ANESTHETIC MANAGEMENT OF TOTAL TETRALOGY OF FALLOT REPAIR IN AN ADULT PATIENT AFTER DIAGNOSIS BY TRANSESOPHAGEAL 5 ECHOCARDIOGRAPHYDUTT AND NGAI

performed at greater than 12 months.16 The higher mortality in adults is thought to be related to longstanding cyanosis resulting in fibrosis of the right ventricle, which causes decreased right ventricular contractility and chronic myocardial hypoxemia. In addition, collateral circulation that develops to improve pulmonary blood flow results in longstanding right ventricular pressure overload. These changes in right ventricular function and anatomy result in a higher frequency of ventricular arrhythmias in patients operated on at an older age. One study found that 25% of patients with right ventricular pressure greater than 60mmHg developed postoperative ventricular arrhythmia compared to an incidence of only 8% in patients with right ventricular pressures less than 40 mmHg.17 Holter monitor capture of ventricular arrhythmias occurs in 40% to 50% of patients who have had a TOF repair.18 Patients who undergo TOF surgical correction after age 13 have a 39% to 42% incidence of ventricular arrhythmia, whereas the incidence is 12% to 17% in children corrected before age 7.15 However, Sullivan et al found that, although ventricular arrhythmias were more common with increasing age of TOF repair, only 2% of patients developed a new ventricular arrhythmia after surgery.19 Preoperative ventricular arrhythmia was a common finding in older patients, which suggests that repair at an earlier age offers the advantage of reduced likelihood of a pre-existing arrhythmia prior to surgery. Other factors associated with a higher risk of ventricular arrhythmias are moderate-to-severe pulmonary regurgitation, prolonged QRS interval, and prolonged cardiopulmonary bypass time. However, it is unclear if these arrhythmias increase the incidence of sudden death. A prospective Holter monitor study of postoperative patients found no correlation between the presence of ventricular arrhythmias and sudden death over a 12-year period.20 Complete atrioventricular block has been observed after repair in a minority of patients and requires pacemaker implantation if it does not resolve spontaneously. Patients with severe right or left ventricular enlargement, elevated right or left ventricular end-diastolic pressures, aortic regurgitation, or tricuspid regurgitation should be considered high risk and may be candidates for palliative shunts.21 Aortic regurgitation is often present because of dilation of the aortic root from chronically carrying the load from 2 ventricles. The most common cardiac anomalies associated with TOF are abnormal coronary artery distribution and abnormal position of the aortic arch. In a study of 100 adult patients, Rammohan et al found that 12 had abnormal coronary artery anatomy.7 Six of these patients had left anterior descending arteries that crossed the RVOT. The potential consequences of such abnormalities are unclear, but knowledge of the anatomy is important because it guides surgical approach. The most common complications after adult TOF repair are residual VSD, residual RVOT obstruction (less common in adults because of milder narrowing), right ventricular diastolic dysfunction, and bleeding. Excessive bleeding is particularly likely to occur when prior palliative shunts need to be dissected; however, this has not been shown to be correlated with increased mortality. In addition, cyanotic congenital heart disease has been shown to be associated with thrombocytopenia, platelet function abnormalities, impaired production and increased consumption of clotting factors, and fibrinolysis.22 The resulting coagulopathy appears to be related to the degree of

cyanosis-induced polycythemia, which is supported by an observed inverse relationship between platelet count and red blood cell volume. Consumption of platelets and clotting factors may be secondary to increased blood viscosity resulting in intravascular stasis and accumulation of fibrin and platelet deposits. Despite the increased surgical mortality, the long-term survival after TOF repair in adults likely is improved when compared to conservative management. Jost et al found that the 10-year survival after TOF repair in adults over the age 40 was 73%, which is significantly less than the expected survival of 91% but far greater than the 24% expected survival to age 10 without TOF repair.10 In addition, quality of life in those patients who survive surgery is greatly improved. John et al found that 97% of long-term survivors were asymptomatic at followup.9 Rammohan et al performed TOF repair in 100 adults.7 Preoperatively, 58% of patients were in New York Heart Association (NYHA) functional class II, and 42% were in class III. At mean followup of 3.4 years, 93.6% of patients were in NYHA class I, 6.31% were in class II, and 1 patient had died of infective endocarditis. The authors’ patient’s clinical presentation was classic for an adult with unrecognized TOF. She developed normally in childhood and functioned well as an adult until she began to develop dyspnea with exertion and chest discomfort. The echocardiographic evidence of her physiologically less-severe form of the defect likely explains why she remained asymptomatic until the age of 55. Specifically, the narrowing of her subpulmonary infundibulum resulted in only moderate RVOT obstruction, which prevented right-to-left flow through the VSD and cyanosis early in life. The relative patency of her RVOT likely also allowed her to tolerate the moderate intraoperative decrease in mean arterial pressure caused by isoflurane. Furthermore, despite the presence of a large VSD, left-to-right shunting was limited by her prolapsed right coronary cusp. This partial obstruction of the VSD may have prevented right ventricular volume overload and failure. As discussed above, these patients often develop symptoms related to a failing right ventricle, left ventricle, or both. The precise etiology of the authors’ patient’s symptoms was complicated by the fact that her right coronary cusp prolapse resulted in severe aortic regurgitation but also a functionally smaller VSD. TEE was significantly more sensitive than TTE in distinguishing this from simple aortic regurgitation. There is little evidence in the literature to suggest that TEE is more effective than TTE in making the diagnosis of a VSD. Leung et al found that TEE was particularly useful in guiding surgical repair in pediatric patients with aortic regurgitation associated with a VSD.23 The authors of this study demonstrated an ability to achieve clear and precise views of these VSDs despite the fact that the aortic valve prolapse in most patients was severe enough to partially or completely obliterate the defect during systole. The transthoracic echocardiographic diagnosis of a VSD may, therefore, be hindered in the setting of aortic valve prolapse. This, combined with the difficulty in obtaining highquality TTE windows in obese adults, may explain the initial misdiagnosis in the authors’ patient. TTE also failed to demonstrate the RVOT obstruction and overriding aorta that helped lead to the diagnosis of TOF and changed surgical management. A number of cases have been reported in which

6

ANESTHETIC MANAGEMENT OF FALLOT REPAIR

TEE identified the cause of LVOT and RVOT obstruction after TTE did not.24 Rare conditions, such as an anterior mitral leaflet aneurysm or postoperative mediastinal hematoma, caused the outflow tract obstruction in the majority of these cases. However, it appears that TEE is able to overcome obstacles related to abnormal anatomy, body habitus, and positioning in certain patients when TTE cannot. The ability of an echocardiographer to position a TEE probe in close proximity to the structures of interest may account for this increased sensitivity, which is especially true for the posterior structures of the heart. In addition, TEE examination of anterior structures rather than TTE may offer better resolution in the presence of excess soft tissue on the chest wall of an obese patient. CONCLUSION

Tetralogy of Fallot is the most common congenital heart defect diagnosed in adults, but survival past childhood is still quite rare. Adults with TOF generally have less severe

pathophysiology that has allowed them to survive without treatment. Although TTE is often used to make the diagnosis of TOF, TEE may be more sensitive in detecting subtle structural abnormalities. Anesthetic management needs to be adjusted based on the severity of RVOT obstruction and potential associated cardiac anomalies. Surgical repair consists of closure of the VSD and relief of the RVOT obstruction. The authors’ patient was deemed to have an adequate pulmonary valve annulus size and thus was able to have a pulmonary valvesparing procedure. This reduces her risk for developing severe pulmonary regurgitation, which would contribute to right ventricular failure. However, her persistent right and left ventricular dilation and hypertrophy leaves her with a higher risk of development of ventricular arrhythmia, which may increase her risk of sudden cardiac death. Despite the increased mortality risk associated with TOF repair in adults, it can be expected that the authors’ patient will have a significant improvement in symptoms and quality of life at followup.

REFERENCES 1. Makaryus AN, Aronov I, Diamond J, et al: Survival to the age of 52 years in a man with unrepaired tetralogy of Fallot. Echocardiography 21:631-637, 2004 2. Hannoush H, Tamim H, Younes H, et al: Patterns of congenital heart disease in unoperated adults: A 20-year experience in a developing country. Clin Cardiol 27:236-240, 2004 3. Brickner ME, Hillis LD, Lange RA: Congenital heart disease in adults. Second of two parts. N Engl J Med 342:334-342, 2000 4. Bertranou EG, Blackstone EH, Hazelrig JB, et al: Life expectancy without surgery in tetralogy of Fallot. Am J Cardiol 42:458-466, 1978 5. Parker SE, Mai CT, Canfield MA, et al: For the National Birth Defects Prevention Network. Updated national birth prevalence estimate for selected birth defects in the United States, 2004-2006. Birth Defects Res A Clin Mol Teratol 88:1008-1016, 2010 6. Motta P, Miller-Hance WC: Transesophageal echocardiography in tetralogy of Fallot. Semin Cardiothorac Vasc Anesth 16:70-87, 2012 7. Rammohan M, Airan B, Bhan A: Total correction of tetralogy of Fallot in adults-surgical experience. Int J Cardiol 63:121-128, 1998 8. McGoon DC, Baird DK, David GD: Surgical management of large bronchial collateral arteries with pulmonary stenosis or atresia. Circulation 52:109-118, 1975 9. John SJ, Kejriwal NK, Ravikumar E, et al: The clinical profile and surgical treatment of tetralogy of Fallot in the adult: Results of repair in 200 patients. Ann Thorac Surg 41:502-506, 1986 10. Jost CA, Connolly HM, Burkhart HM, et al: Tetralogy of Fallot repair in patients 40 years or older. Mayo Clin Proc 85:1090-1094, 2010 11. Dietl CA, Torres AR, Cazzaniga ME, et al: Right atrial approach for surgical correction of tetralogy of Fallot. Ann Thorac Surg 47:546-552, 1989 12. Finck SJ, Puga FJ, Danielson GK: Pulmonary valve insertion during reoperation for tetralogy of Fallot. Ann Thorac Surg 45:610-613, 1988 13. Harrild DM, Berul CI, Cecchin F, et al: Pulmonary valve replacement in tetralogy of Fallot. impact on survival and ventricular tachycardia. Circulation 119:445-451, 2009

14. Stewart RD, Backer CL, Young L, et al: Tetralogy of Fallot: Results of a pulmonary valve sparing strategy. Ann Thorac Surg 80: 1431-1439, 2005 15. Presbitero P, Demarie D, Aruta E, et al: Results of total correction of tetralogy of Fallot performed in adults. Ann Thorac Surg 61:1870-1873, 1996 16. Van Arsdell GS, Maharaj GS, Tom L, et al: Surgery for congenital heart disease. What is the optimal age for repair of tetralogy of Fallot? Circulation 102(Suppl III):III-123-III-129, 2000 17. Garson A, Randall DC, Gillete PC, et al: Prevention of sudden cardiac death after repair of tetralogy of Fallot: Treatment of ventricular arrhythmias. J Am Coll Cardiol 6:221-227, 1985 18. Vaksmann G, Fournier A, Davignon A, et al: Frequency and prognosis of arrhythmias after operative “correction” of tetralogy of Fallot. Am J Cardiol 66:346-349, 1990 19. Sullivan ID, Presbitero P, Gooch VM, et al: Is ventricular arrhythmia in repaired tetralogy of Fallot an effect of operation or a consequence of the course of the disease? A prospective study. Br Heart J 58:40-44, 1987 20. Cullen S, Celermajer DS, Franklin RG, et al: Prognostic significance of ventricular arrhythmia after repair of tetralogy of Fallot: A 12-year prospective study. J Am Coll Cardiol 23:1151-1155, 1994 21. Dittrich S, Vogel M, Dahnert I, et al: Surgical repair of tetralogy of Fallot in adults today. Clin Cardiol 22:460-464, 1999 22. Tempe DK, Virmani S: Coagulation abnormalities in patients with cyanotic congenital heart disease. J Cardiothorac Vasc Anesth 15: 752-765, 2002 23. Leung MP, Chau K, Chiu C, et al: Intraoperative TEE assessment of ventricular septal defect with aortic regurgitation. Ann Thorac Surg 61:854-860, 1996 24. Shively BK: Transesophageal echocardiographic (TEE) evaluation of the aortic valve, left ventricular outflow tract, and pulmonic valve. Cardiol Clin 18:711-729, 2000