Original Article
Minimally invasive mitral valve surgery via minithoracotomy and direct cannulation
Asian Cardiovascular & Thoracic Annals 2015, Vol. 23(3) 271–274 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314544309 aan.sagepub.com
Mohammad H Nezafati, Pouya Nezafati, Mahmoud Hosseinzadeh and Sahar Omidvar Tehrani
Abstract Background: To reduce the morbidity of mitral valve operations, a right anterolateral minithoracotomy under direct vision was introduced. We report our experience with this procedure. Methods: From July 2001 to December 2013, 320 consecutive patients underwent direct minimally invasive mitral valve surgery through a right anterolateral minithoracotomy at our institution. Evidence of rheumatic disease was observed in 231 (72%) patients, and 89 (28%) repaired valves had myxomatous changes. Tricuspid valve repair was performed in 80 (25%) patients and radiofrequency ablation in 80 (25%) with chronic atrial fibrillation. All cannulas were introduced through the thoracotomy incision, eliminating femoral cannulation. No new instruments, retractors, or ports were used. Pleural and pericardial drainage was accomplished through a single drain. Results: There was no hospital death. Conversion to sternotomy was needed in 3 patients because we were unable to obtain satisfactory arterial cannulation. Eight patients required reoperation: 7 for mitral insufficiency and one for postoperative bleeding. Mean cardiopulmonary bypass and crossclamp times were 55.3 17.0 and 43.0 13.4 min, respectively. Mean intensive care unit stay was 29 h, and hospital stay was 4.3 days. Conclusions: Based on our experience, this minimally invasive approach is safe, rapid, cost-effective, and more comfortable for the patients, in addition to its cosmetic benefits. It may be the preferred approach in young females.
Keywords Heart valve diseases, heart valve prosthesis implantation, mitral valve, surgical procedures, minimally invasive, thoracotomy
Introduction Minimally invasive techniques of mitral valve surgery have been increasingly applied to improve patient outcome since the mid 1990s. In specialized centers, these techniques have evolved as the clinical standard, allowing the procedure to be performed safely. Improvements in surgical technique and setup allow accomplishment via minimal access of the same quality as conventional mitral valve surgery, with less surgical trauma, reduced pain and recovery time, and a better cosmetic outcome, resulting in improved patient satisfaction.1 However, most mitral valve operations are performed through a midline sternotomy, creating a wound that has huge physical and psychological effects, especially in female patients. Some patients have refused necessary cardiac surgery because of the midline scar. As other surgical disciplines follow the trend
of reduced invasiveness, recent advances have made less-invasive cardiac surgery feasible. The safety and reproducibility of minimally invasive mitral valve surgery are well documented.2 Various minimally invasive approaches for mitral valve operations have been advocated as technologies have been developed. These various approaches include minithoracotomies, partial sternotomies, and parasternal incisions.2–6 In our center, we focused on evaluating the feasibility of minimally invasive mitral valve surgery via a
Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Corresponding author: Pouya Nezafati, No. 128 8th Niloufar St., Sadjad Blvd., Mashhad, Iran. Email: [email protected]
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
272
Asian Cardiovascular & Thoracic Annals 23(3)
minithoracotomy. Maintaining at least the same level of safety and favorable results as conventional surgery was the main goal. This study reports our experience with minimally invasive mitral valve surgery via an anterolateral minithoracotomy, avoiding any peripheral cannulation, and providing adequate mitral valve exposure.
Patients and methods This study was conducted in accordance with the principles of Declaration of Helsinki 1996 and Good Practice standards. All subjects signed informed consent forms. From July 2001 to December 2013, 320 patients underwent minimally invasive mitral valve surgery through a right anterolateral minithoracotomy. All patients were preoperatively assessed to ensure the suitability of the designated approach. Exclusion criteria were concomitant aortic valve dysfunction, coronary artery disease, body mass index >32 kg m2, and failure to give informed consent. The preoperative clinical characteristics of the patients are summarized in Table 1. Under general anesthesia, all patients were intubated with a double-lumen endotracheal tube and placed in the supine position with the arms tucked and right shoulder slightly elevated. The chest was prepared and draped to enable a sternotomy should this become necessary. Transesophageal echocardiographic monitoring was performed in all procedures to assess the mitral valve and deairing. Standard hemodynamic monitoring was used and external defibrillator pads were placed posteriorly and anteriorly on the lateral left chest wall. The right lung was deflated and a small thoracotomy was performed in the fourth intercostal space through a 6–7 cm right submammary skin
incision. A right chest retractor was placed and gradually opened to prevent cartilage damage and rib fracture. The right internal mammary artery was carefully identified and protected from any trauma. The pericardium was incised longitudinally anterior to the phrenic nerve, and the edges were suspended from the chest wall to elevate the right side of the heart. Heparin was administered to achieve an activated coagulation time of 450 s. An aorto-bicaval cannula (arterial cannula, straight tip with flange; Maquet) and a right atrial cannula (DLP malleable single stage venous cannula; Medtronic) were placed, a suction-vent cardioplegia catheter was conventionally sited directly through the thoracotomy, and cardiopulmonary bypass initiated. After cooling to 32 C, the aorta was crossclamped using a standard aortic clamp through the thoracotomy. Consequently, intermittent antegrade blood cardioplegia could be used to provide superb myocardial protection (Figure 1). The mitral valve was approached through the interatrial groove (Cooley atrial retractor, USA pattern; Geister) and repaired or replaced as deemed necessary (Figure 2). The posterior leaflet-sparing technique was used in more than 50% of cases, but the leaflet was resected in advanced rheumatismal or thickened valves. Tricuspid repair and ablation were also performed when necessary. For radiofrequency ablation, a Cobra device (Boston Scientific Corporation) was used. The system consists of a flexible surgical probe with 7 electrode terminals for separate or combined use (which creates continuous linear lesion), a generator of radiofrequency ablation energy, an ablation controller, and connecting cables. Ablation was undertaken using radiofrequency for 1 min on each lesion. The left atrium was closed routinely after the main procedures were performed. The patient was weaned from cardiopulmonary bypass following rewarming to 37 C. A single drain with 2 additional
Table 1. Preoperative characteristics of 320 patients undergoing mitral valve replacement via a right minithoracotomy. Patient characteristics Mean age Male / Female NYHA functional class Class I Class II Class III Class IV Valvular pathology Rheumatic Degenerative
43.3 9.3 181/139 9 34 75 2 216 104
Figure 1. The submammary right incision and location of chest tube.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
Nezafati et al.
273 Table 2. Results of mitral valve surgery via a right minithoracotomy in 320 patients. Mean cross-clamp time. Min Mean CPB time, min Mean ventilation time, hrs Mean length of ICU stay, hrs Mean Legend of hospital stay, days Complication Mortality Re-operation Conversion to sternotomy Infection
Figure 2. Direct aortic and caval cannulation. A ¼ aortic cannula, C ¼ cardioplegia cannula, V ¼ venous cannulas.
43.0 13.4 55.3 17.0 6.4 2.8 37 8.7 8.1 2.2 0 8 3 0
bleeding or mitral insufficiency, but there was no hospital mortality (Table 2).
Discussion
Figure 3. Placement of the mattress sutures in the sewing ring of a bileaflet prosthesis.
lateral holes was inserted though the 7th intercostal space on the midaxillary line, so that the tip of the drain reached the pericardial cavity and the lateral holes were placed in the pleural space. The chest was closed in layers, and intercostal block was carried out by Marcaine injection (Figure 3). Data were collected prospectively by trained clinicians. Results are expressed as mean standard deviation. Statistical analysis was performed using SPSS version 5 software (SPSS, Inc., Chicago, IL, USA.
Results The mitral valve was repaired in 89 (28%) patients and replaced in 231 (72%). Tricuspid valve repair was performed in 80 (25%) patients and radiofrequency ablation in 80 (25%). The procedure was converted to a sternotomy in 3 (0.94%) patients due to inability to obtain satisfactory arterial cannulation. Eight patients underwent reoperation due to excessive postoperative
Numerous studies have shown that minimally invasive valve surgery is a safe and effective procedure with similar if not improved morbidity and mortality rates compared to conventional valve surgery.9 For the surgeon who elects to use a minimally invasive approach for mitral valve operations, many choices of technique are available. Decisions have to be made about the type of incision and the use of direct aortic or femoral cannulation, a balloon EndoClamp or direct aortic crossclamping, video assistance or direct observation, and other technical aspects, many of which are interrelated.10 While some techniques minimize the extent of the access, they still require a partial sternotomy, and others require peripheral arterial cannulation or the use of expensive endoscopic equipment not available to the majority of practicing surgeons. Minimally invasive direct mitral valve surgery through a right minithoracotomy approach proved to be easy to learn and has many other advantages such as shorter intensive are unit stay and hospitalization, less blood loss (resulting from elimination of the sternotomy), less pain, much less chest tube drainage, avoidance of the complications of femoral cannulation, protection of the right internal mammary artery, and totally eradicating the risk of deep sternal infection. One of the main advantages of this approach may be in the reoperative setting. The potential advantages of approaching the mitral valve through a right thoracotomy in the reoperative setting are the avoidance of patent bypass grafts including the left internal mammary artery, less dissection, improved mitral exposure, and less bleeding.11–13 To eliminate the risk of complications such as infection and obtain better cosmetic results, we did not utilize any peripheral cannulation.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
274
Asian Cardiovascular & Thoracic Annals 23(3)
One of the disadvantages of this minimally invasive approach through a right thoracotomy is that there is a learning curve for the surgeon and team to be able to perform the procedure through a smaller incision with a right chest retractor, suitable aortic clamp, and arterial and venous cannulae.14 Also, we had to exclude patients with a body mass index greater than 32 kg m2 because the greater amount of fatty tissue restricts performance of the procedure through the small incision. This study revealed that minimally invasive direct mitral valve surgery through a right minithoracotomy using standard cardiopulmonary bypass is a good alternative to the conventional open surgical method. Excellent cosmetic results and avoidance of sternal complications are the major advantages. This technique deserves a place in the surgical armamentarium for mitral valve treatment, to improve patient satisfaction. We believe that using a minithoracotomy and direct vision, a simple modification of techniques alone is required, thus facilitating a surgeon’s transition from the traditional sternotomy. Acknowledgments Presented at Valves in the Heart of the Big Apple VI: Evaluation & Management of Valvular Heart Disease, New York, April 15–17, 2010.
Funding This research received no specific grant from any funding agency in the public, commerical, or not-for-profit sectors.
Conflict of interest statement None declared.
References 1. Aybek T, Dogan S, Risteski PS, et al. Two hundred forty minimally invasive mitral operations through right minithoracotomy. Ann Thorac Surg 2006; 81: 1618–1624.
2. Chiu KM, Lin TY, Li SJ, Chen JS and Chu SH. Less invasive mitral valve surgery via right minithoracotomy. J Formos Med Assoc 2006; 105: 715–721. 3. Grossi EA, La Pietra A, Galloway AC and Colvin SB. Videoscopic mitral valve repair and replacement using the port-access technique. Adv Card Surg 2001; 13: 77–88. 4. Gundry SR, Shattuck OH, Razzouk AJ, del Rio MJ, Sardari FF and Bailey LL. Facile minimally invasive cardiac surgery via ministernotomy. Ann Thorac Surg 1998; 65: 1100–1104. 5. Nair RU and Sharpe DA. Limited lower sternotomy for minimally invasive mitral valve replacement. Ann Thorac Surg 1998; 65: 273–274. 6. Gillinov AM, Banbury MK and Cosgrove DM. Hemisternotomy approach for aortic and mitral valve surgery. J Card Surg 2000; 15: 15–20. 7. Cohn LH, Adams DH, Couper GS, et al. Minimally invasive cardiac valve surgery improves patient satisfaction while reducing costs of cardiac valve replacement and repair. Ann Surg 1997; 226: 421–426. 8. Cosgrove DM 3rd, Sabik JF and Navia JL. Minimally invasive valve operations. Ann Thorac Surg 1998; 65: 1535–1538. 9. Soltesz EG and Cohn LH. Minimally invasive valve surgery [Review]. Cardiol Rev 2007; 15: 109–115. 10. Grossi EA, Galloway AC, LaPietra A, et al. Minimally invasive mitral valve surgery: a 6-year experience with 714 patients. Ann Thorac Surg 2002; 74: 660–663. 11. Cohn LH. As originally published in 1989: right thoracotomy, femorofemoral bypass, and deep hypothermia for re-replacement of the mitral valve. Updated in 1997. Ann Thorac Surg 1997; 64: 578–579. 12. Byrne JG, Aranki SF, Adams DH, Rizzo RJ, Couper GS and Cohn LH. Mitral valve surgery after previous CABG with functioning IMA grafts. Ann Thorac Surg 1999; 68: 2243–2247. 13. Burfeind WR, Glower DD, Davis RD, Landolfo KP, Lowe JE and Wolfe WG. Mitral surgery after prior cardiac operation: port-access versus sternotomy or thoracotomy. Ann Thorac Surg 2002; 74: S1323–S1325. 14. El-Fiky MM, El-Sayegh T, El-Beishry AS, et al. Limited right anterolateral thoracotomy for mitral valve surgery. Eur J Cardiothorac Surg 2000; 17: 710–713.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
Minimally invasive mitral valve surgery via minithoracotomy and direct cannulation
Asian Cardiovascular & Thoracic Annals 2015, Vol. 23(3) 271–274 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314544309 aan.sagepub.com
Mohammad H Nezafati, Pouya Nezafati, Mahmoud Hosseinzadeh and Sahar Omidvar Tehrani
Abstract Background: To reduce the morbidity of mitral valve operations, a right anterolateral minithoracotomy under direct vision was introduced. We report our experience with this procedure. Methods: From July 2001 to December 2013, 320 consecutive patients underwent direct minimally invasive mitral valve surgery through a right anterolateral minithoracotomy at our institution. Evidence of rheumatic disease was observed in 231 (72%) patients, and 89 (28%) repaired valves had myxomatous changes. Tricuspid valve repair was performed in 80 (25%) patients and radiofrequency ablation in 80 (25%) with chronic atrial fibrillation. All cannulas were introduced through the thoracotomy incision, eliminating femoral cannulation. No new instruments, retractors, or ports were used. Pleural and pericardial drainage was accomplished through a single drain. Results: There was no hospital death. Conversion to sternotomy was needed in 3 patients because we were unable to obtain satisfactory arterial cannulation. Eight patients required reoperation: 7 for mitral insufficiency and one for postoperative bleeding. Mean cardiopulmonary bypass and crossclamp times were 55.3 17.0 and 43.0 13.4 min, respectively. Mean intensive care unit stay was 29 h, and hospital stay was 4.3 days. Conclusions: Based on our experience, this minimally invasive approach is safe, rapid, cost-effective, and more comfortable for the patients, in addition to its cosmetic benefits. It may be the preferred approach in young females.
Keywords Heart valve diseases, heart valve prosthesis implantation, mitral valve, surgical procedures, minimally invasive, thoracotomy
Introduction Minimally invasive techniques of mitral valve surgery have been increasingly applied to improve patient outcome since the mid 1990s. In specialized centers, these techniques have evolved as the clinical standard, allowing the procedure to be performed safely. Improvements in surgical technique and setup allow accomplishment via minimal access of the same quality as conventional mitral valve surgery, with less surgical trauma, reduced pain and recovery time, and a better cosmetic outcome, resulting in improved patient satisfaction.1 However, most mitral valve operations are performed through a midline sternotomy, creating a wound that has huge physical and psychological effects, especially in female patients. Some patients have refused necessary cardiac surgery because of the midline scar. As other surgical disciplines follow the trend
of reduced invasiveness, recent advances have made less-invasive cardiac surgery feasible. The safety and reproducibility of minimally invasive mitral valve surgery are well documented.2 Various minimally invasive approaches for mitral valve operations have been advocated as technologies have been developed. These various approaches include minithoracotomies, partial sternotomies, and parasternal incisions.2–6 In our center, we focused on evaluating the feasibility of minimally invasive mitral valve surgery via a
Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Corresponding author: Pouya Nezafati, No. 128 8th Niloufar St., Sadjad Blvd., Mashhad, Iran. Email: [email protected]
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
272
Asian Cardiovascular & Thoracic Annals 23(3)
minithoracotomy. Maintaining at least the same level of safety and favorable results as conventional surgery was the main goal. This study reports our experience with minimally invasive mitral valve surgery via an anterolateral minithoracotomy, avoiding any peripheral cannulation, and providing adequate mitral valve exposure.
Patients and methods This study was conducted in accordance with the principles of Declaration of Helsinki 1996 and Good Practice standards. All subjects signed informed consent forms. From July 2001 to December 2013, 320 patients underwent minimally invasive mitral valve surgery through a right anterolateral minithoracotomy. All patients were preoperatively assessed to ensure the suitability of the designated approach. Exclusion criteria were concomitant aortic valve dysfunction, coronary artery disease, body mass index >32 kg m2, and failure to give informed consent. The preoperative clinical characteristics of the patients are summarized in Table 1. Under general anesthesia, all patients were intubated with a double-lumen endotracheal tube and placed in the supine position with the arms tucked and right shoulder slightly elevated. The chest was prepared and draped to enable a sternotomy should this become necessary. Transesophageal echocardiographic monitoring was performed in all procedures to assess the mitral valve and deairing. Standard hemodynamic monitoring was used and external defibrillator pads were placed posteriorly and anteriorly on the lateral left chest wall. The right lung was deflated and a small thoracotomy was performed in the fourth intercostal space through a 6–7 cm right submammary skin
incision. A right chest retractor was placed and gradually opened to prevent cartilage damage and rib fracture. The right internal mammary artery was carefully identified and protected from any trauma. The pericardium was incised longitudinally anterior to the phrenic nerve, and the edges were suspended from the chest wall to elevate the right side of the heart. Heparin was administered to achieve an activated coagulation time of 450 s. An aorto-bicaval cannula (arterial cannula, straight tip with flange; Maquet) and a right atrial cannula (DLP malleable single stage venous cannula; Medtronic) were placed, a suction-vent cardioplegia catheter was conventionally sited directly through the thoracotomy, and cardiopulmonary bypass initiated. After cooling to 32 C, the aorta was crossclamped using a standard aortic clamp through the thoracotomy. Consequently, intermittent antegrade blood cardioplegia could be used to provide superb myocardial protection (Figure 1). The mitral valve was approached through the interatrial groove (Cooley atrial retractor, USA pattern; Geister) and repaired or replaced as deemed necessary (Figure 2). The posterior leaflet-sparing technique was used in more than 50% of cases, but the leaflet was resected in advanced rheumatismal or thickened valves. Tricuspid repair and ablation were also performed when necessary. For radiofrequency ablation, a Cobra device (Boston Scientific Corporation) was used. The system consists of a flexible surgical probe with 7 electrode terminals for separate or combined use (which creates continuous linear lesion), a generator of radiofrequency ablation energy, an ablation controller, and connecting cables. Ablation was undertaken using radiofrequency for 1 min on each lesion. The left atrium was closed routinely after the main procedures were performed. The patient was weaned from cardiopulmonary bypass following rewarming to 37 C. A single drain with 2 additional
Table 1. Preoperative characteristics of 320 patients undergoing mitral valve replacement via a right minithoracotomy. Patient characteristics Mean age Male / Female NYHA functional class Class I Class II Class III Class IV Valvular pathology Rheumatic Degenerative
43.3 9.3 181/139 9 34 75 2 216 104
Figure 1. The submammary right incision and location of chest tube.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
Nezafati et al.
273 Table 2. Results of mitral valve surgery via a right minithoracotomy in 320 patients. Mean cross-clamp time. Min Mean CPB time, min Mean ventilation time, hrs Mean length of ICU stay, hrs Mean Legend of hospital stay, days Complication Mortality Re-operation Conversion to sternotomy Infection
Figure 2. Direct aortic and caval cannulation. A ¼ aortic cannula, C ¼ cardioplegia cannula, V ¼ venous cannulas.
43.0 13.4 55.3 17.0 6.4 2.8 37 8.7 8.1 2.2 0 8 3 0
bleeding or mitral insufficiency, but there was no hospital mortality (Table 2).
Discussion
Figure 3. Placement of the mattress sutures in the sewing ring of a bileaflet prosthesis.
lateral holes was inserted though the 7th intercostal space on the midaxillary line, so that the tip of the drain reached the pericardial cavity and the lateral holes were placed in the pleural space. The chest was closed in layers, and intercostal block was carried out by Marcaine injection (Figure 3). Data were collected prospectively by trained clinicians. Results are expressed as mean standard deviation. Statistical analysis was performed using SPSS version 5 software (SPSS, Inc., Chicago, IL, USA.
Results The mitral valve was repaired in 89 (28%) patients and replaced in 231 (72%). Tricuspid valve repair was performed in 80 (25%) patients and radiofrequency ablation in 80 (25%). The procedure was converted to a sternotomy in 3 (0.94%) patients due to inability to obtain satisfactory arterial cannulation. Eight patients underwent reoperation due to excessive postoperative
Numerous studies have shown that minimally invasive valve surgery is a safe and effective procedure with similar if not improved morbidity and mortality rates compared to conventional valve surgery.9 For the surgeon who elects to use a minimally invasive approach for mitral valve operations, many choices of technique are available. Decisions have to be made about the type of incision and the use of direct aortic or femoral cannulation, a balloon EndoClamp or direct aortic crossclamping, video assistance or direct observation, and other technical aspects, many of which are interrelated.10 While some techniques minimize the extent of the access, they still require a partial sternotomy, and others require peripheral arterial cannulation or the use of expensive endoscopic equipment not available to the majority of practicing surgeons. Minimally invasive direct mitral valve surgery through a right minithoracotomy approach proved to be easy to learn and has many other advantages such as shorter intensive are unit stay and hospitalization, less blood loss (resulting from elimination of the sternotomy), less pain, much less chest tube drainage, avoidance of the complications of femoral cannulation, protection of the right internal mammary artery, and totally eradicating the risk of deep sternal infection. One of the main advantages of this approach may be in the reoperative setting. The potential advantages of approaching the mitral valve through a right thoracotomy in the reoperative setting are the avoidance of patent bypass grafts including the left internal mammary artery, less dissection, improved mitral exposure, and less bleeding.11–13 To eliminate the risk of complications such as infection and obtain better cosmetic results, we did not utilize any peripheral cannulation.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
274
Asian Cardiovascular & Thoracic Annals 23(3)
One of the disadvantages of this minimally invasive approach through a right thoracotomy is that there is a learning curve for the surgeon and team to be able to perform the procedure through a smaller incision with a right chest retractor, suitable aortic clamp, and arterial and venous cannulae.14 Also, we had to exclude patients with a body mass index greater than 32 kg m2 because the greater amount of fatty tissue restricts performance of the procedure through the small incision. This study revealed that minimally invasive direct mitral valve surgery through a right minithoracotomy using standard cardiopulmonary bypass is a good alternative to the conventional open surgical method. Excellent cosmetic results and avoidance of sternal complications are the major advantages. This technique deserves a place in the surgical armamentarium for mitral valve treatment, to improve patient satisfaction. We believe that using a minithoracotomy and direct vision, a simple modification of techniques alone is required, thus facilitating a surgeon’s transition from the traditional sternotomy. Acknowledgments Presented at Valves in the Heart of the Big Apple VI: Evaluation & Management of Valvular Heart Disease, New York, April 15–17, 2010.
Funding This research received no specific grant from any funding agency in the public, commerical, or not-for-profit sectors.
Conflict of interest statement None declared.
References 1. Aybek T, Dogan S, Risteski PS, et al. Two hundred forty minimally invasive mitral operations through right minithoracotomy. Ann Thorac Surg 2006; 81: 1618–1624.
2. Chiu KM, Lin TY, Li SJ, Chen JS and Chu SH. Less invasive mitral valve surgery via right minithoracotomy. J Formos Med Assoc 2006; 105: 715–721. 3. Grossi EA, La Pietra A, Galloway AC and Colvin SB. Videoscopic mitral valve repair and replacement using the port-access technique. Adv Card Surg 2001; 13: 77–88. 4. Gundry SR, Shattuck OH, Razzouk AJ, del Rio MJ, Sardari FF and Bailey LL. Facile minimally invasive cardiac surgery via ministernotomy. Ann Thorac Surg 1998; 65: 1100–1104. 5. Nair RU and Sharpe DA. Limited lower sternotomy for minimally invasive mitral valve replacement. Ann Thorac Surg 1998; 65: 273–274. 6. Gillinov AM, Banbury MK and Cosgrove DM. Hemisternotomy approach for aortic and mitral valve surgery. J Card Surg 2000; 15: 15–20. 7. Cohn LH, Adams DH, Couper GS, et al. Minimally invasive cardiac valve surgery improves patient satisfaction while reducing costs of cardiac valve replacement and repair. Ann Surg 1997; 226: 421–426. 8. Cosgrove DM 3rd, Sabik JF and Navia JL. Minimally invasive valve operations. Ann Thorac Surg 1998; 65: 1535–1538. 9. Soltesz EG and Cohn LH. Minimally invasive valve surgery [Review]. Cardiol Rev 2007; 15: 109–115. 10. Grossi EA, Galloway AC, LaPietra A, et al. Minimally invasive mitral valve surgery: a 6-year experience with 714 patients. Ann Thorac Surg 2002; 74: 660–663. 11. Cohn LH. As originally published in 1989: right thoracotomy, femorofemoral bypass, and deep hypothermia for re-replacement of the mitral valve. Updated in 1997. Ann Thorac Surg 1997; 64: 578–579. 12. Byrne JG, Aranki SF, Adams DH, Rizzo RJ, Couper GS and Cohn LH. Mitral valve surgery after previous CABG with functioning IMA grafts. Ann Thorac Surg 1999; 68: 2243–2247. 13. Burfeind WR, Glower DD, Davis RD, Landolfo KP, Lowe JE and Wolfe WG. Mitral surgery after prior cardiac operation: port-access versus sternotomy or thoracotomy. Ann Thorac Surg 2002; 74: S1323–S1325. 14. El-Fiky MM, El-Sayegh T, El-Beishry AS, et al. Limited right anterolateral thoracotomy for mitral valve surgery. Eur J Cardiothorac Surg 2000; 17: 710–713.
Downloaded from aan.sagepub.com at KAI NAN UNIV on February 27, 2015
