Redo Mitral Valve Surgery-A Long-Term Experience

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Redo Mitral Valve Surgery— A Long-Term Experience Arkalgud Sampath Kumar, M.Ch., Jayesh Dhareshwar, M.S., Balram Airan, M.Ch., Anil Bhan, M.Ch., Rajesh Sharma, M.Ch., and Panangipalli Venugopal, M.Ch. Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India ABSTRACT Background: Our experience with reoperative mitral valve (MV) surgery over a 27-year period is presented here. Methods: From January 1975 to June 2002, 11,908 operations were performed for MV disease. Out of these 744 were reoperations. The mean age at primary operation was 23.6 ± 10.1 years (range 2 to 53 years) and at reoperation was 36.0 ± 11.0 years (range 6 to 65 years) with a mean interval of 11.5 ± 2.5 years. Mitral valve replacement (MVR) was performed following previous closed mitral valvotomy (CMV) in 408 patients, open mitral commissurotomy (OMC) in 21 patients, and MV repair in 58 patients, MVR in 80 patients, homograft mitral valve replacement (HMVR) in 11 patients. The reasons for reoperation were mainly progression of lesions. Valve thrombosis and endocarditis were indications for reoperation following MVR. Twenty-eight patients underwent redo CMV, 53 patients underwent OMC, and 14 patients underwent MV Repair. Results: Early mortality was 5.64% (n = 42). Hemorrhage and low cardiac output were the major causes. Follow-up was 124.8 ± 30.5 months (2 to 300 months). Follow-up was 88%. There were no late deaths in the valve repair group. There were three episodes of thromboembolism in this group (0.3% per patient-year). In the valve replacement group there were six late deaths; three due to valve thrombosis, one due to infective endocarditis, and two due to anticoagulant-related hemorrhage. There were 13 episodes of thromboembolism in this group (0.6% per patient-year). Conclusion: Redo MV surgery is safe and can be undertaken with acceptable mortality and morbidity. (J Card Surg 2004;19:303-307)

Surgery for rheumatic MV lesions is palliative. Despite the advances in techniques, myocardial protection and valve design; the problem of reoperation remains. This is due to the following: 1. 2. 3. 4.

young age of the patients, progressive nature of the disease, thrombogenicity of the prosthetic valves, and degeneration of the bioprosthetic/homograft valves.

Reoperations are technically more demanding, and in the past have been associated with a considerably higher mortality than primary valve operations.1 We share our experience of reoperative MV surgery over a period of 27 years. PATIENTS AND METHODS From January 1975 to June 2002, 11,908 operations were performed for MV disease (Table 1). Of these 744 were reoperations. These patients were evaluated retrospectively for the various indications for reoperation, early morbidity and mortality, and late results. Of the 744 patients who were reoperated for MV disease, 498 were males (67%), and 246 were females (33%). The mean age of the patients at the primary Address for correspondence: Arkalgud Sampath Kumar, Professor, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India. Telefax: +91-11-26588889; Fax: +91-11-2658863; 26588641; e-mail: asampath [email protected]

operation was 23.6 ± 10.1 years (range 2 to 53 years) and at reoperation was 36.0 ± 11.0 years (range 6 to 65 years) with a mean interval of 11.5 ± 2.5 years (range 0.5 to 35 years) between the two procedures. Mitral valve replacements (MVR) were performed following previous closed mitral valvotomy (CMV) in 408 patients (mean interval 14.2 years), open mitral commissurotomy (OMC) in 21 patients (mean interval 5.1 years), mitral valve (MV) Repair in 58 patients (mean interval 6.1 years), MVR in 80 patients (mean interval 3.2 years), and homograft mitral valve replacement (HMVR) in 11 patients (mean interval 2.8 years). The reasons for reoperation were mainly progression of lesions following previous CMV/OMC/MV repair. Prosthetic valve thrombosis and infective endocarditis were the principal indication of reoperation following MVR. In addition, 28 patients underwent redo CMV (mean interval 10.2 years). Other MV procedures performed were: OMC in 53 patients (mean interval 14.9 years) following previous CMV/OMC and MV repair in 14 patients (mean interval 4.4 years) following previous CMV/MV repair. Mid-sternotomy was the incision of choice (n = 711). A right anterolateral thoracotomy approach was used in five patients. Early morbidity included one or more of the following complications: excessive postoperative bleeding (more than 1 L in 24 hours in adults), reexploration, low output syndrome, arrhythmias, prolonged ventilation and intensive care unit stay, renal failure, early thromboembolism, chest infection, and sternal dehiscence.

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TABLE 1 Valve Operations Performed from January 1975 to June 2002 Operation

Number

Closed mitral valvotomy Open mitral commissurotomy Mitral valve replacement Mitral valve repair Homograft mitral valve replacement Multiple valve replacement Total procedures

5705 442 3345 1174 37 1205 11,908

Early mortality included all deaths occurring before discharge or within 30 days of operation. At the time of reoperation 208 patients (28%) were in New York Heart Association (NYHA) class II, 461 (62%) were in class III, and 75 (10%) were in class IV. Four hundred and eighty-three patients (65%) were in atrial fibrillation, while 261 patients (35%) were in normal sinus rhythm. As an institutional protocol, all patients with suspected multivalvular disease on echocardiography and age more than 40 years (to rule out coronary artery disease) underwent cardiac catheterization before surgery. Five hundred and thirty-six patients underwent cardiac catheterization prior to the operation. Of these 425 patients were found to have moderate-or-severe pulmonary artery hypertension. The mean systolic pulmonary artery pressure was 62 mmHg and mean pulmonary artery pressure was 43 mmHg. Reoperations following previous closed mitral valvotomy Of the 548 patients who underwent CMV, 28 returned for repeat CMV for restenosis (mean interval 10.2 years) (Table 2). Young age, sinus rhythm, and pliable valve morphology prompted a second closed procedure. Five hundred and twenty patients required an open heart operation: OMC in 52 patients (mean interval 15.2 years), MVR in 408 patients (mean interval

14.2 years), double valve replacement (DVR) in 47 patients (mean interval 11.8 years), MV repair in 9 patients (mean interval 4.7 years), HMVR in 2 patients, and aortic valve replacement in 2 patients. Following CMV, the predominant lesion requiring MVR was severe mitral stenosis (MS) in 404 patients (73.7%). Thirty-seven patients (6.7%) had mitral regurgitation (MR) as the predominant lesion and 57 patients (10.4%) had MR along with MS as the indication for reoperation. Operations following open heart procedures for mitral valve Of the 196 patients in this category, 170 patients had undergone the primary operation at our institution and 26 patients had been operated elsewhere. Valve thrombosis (54 patients), paravalvular leak (13 patients), prosthetic valve endocarditis (10 patients), bioprosthetic valve degeneration (11 patients), homograft degeneration (11 patients), failed MV repair (64 patients), or restenosis/regurgitation following commissurotomy (23 patients) were indications for surgery. After HMVR, 11 patients underwent reoperations for severe MR after an interval ranging from 6 weeks to 58 months (mean 2.8 months). Donor papillary muscle disruption was responsible for early failures (n = 3), whereas cusprelated pathology was primarily responsible for late failures (n = 8). In all patients the homograft was replaced with a St. Jude Medical mitral prosthesis. Development of aortic regurgitation or stenosis was the indication for reoperation in six patients (Tables 3 and 4). Associated tricuspid valve disease, in the form of moderateto-severe tricuspid regurgitation (TR) was present in 39 patients (23%). However, tricuspid valve repair was performed in only 20 of these patients. Mitral valve replacements were performed following previous CMV in 408 patients (mean interval 14.2 years), OMC in 21 patients (mean interval 5.1 years), MV Repair in 58 patients (mean interval 6.1 years), MVR in 80 patients (mean interval 3.2 years), and HMVR in 11 patients (mean interval 2.8 years). The reasons for reoperation were mainly progression of lesions following previous CMV/OMC/MV repair.

TABLE 2 Reoperations Following CMV Indications for Operation CMV (N = 548) MS (n = 404)

MS + MR (n = 57) MR (n = 37) Aortic Valve Disease (n = 50)

Procedures

No. of Patients

Mean Interval (years)

Mortality (number)

CMV MVR HMVR OMC MVR MVR MV repair DVR HAVR + OMC AVR

28 323 2 51 57 28 9 47 1 2

10.2 14.6 14 15.2 14.9 9.05 4.7 11.8 14.6 8.4

0 17 1 1 3 2 0 0 0 1

MS = mitral stenosis, MR = mitral regurgitation, CMV = closed mitral valvotomy, MVR = mitral valve replacement, HMVR = homograft mitral valve replacement, OMC = open mitral commissurotomy, DVR = double valve replacement, AVR = aortic valve replacement, HAVR = homograft aortic valve replacement.

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TABLE 3 Reoperation Following Previous Open Heart Surgery (Prior Valve Repair) 1st Operation (N = 87)

Indication for Reoperation

Type of Reoperation

No. of Patients

Mean Interval (years)

Mortality (Number)

MV Repair (N = 64)

Severe MR

OMC (N = 23)

AR MS

MVR MV Repair HMVR DVR MVR OMC MVR MV Repair DVR

57 4 2 1 16 1 4 1 1

6.2 4.2 2.4 3.2 5.4 2.4 4.2 3.2 4.8

3 1 1 0 0 0 0 0 0

MR AR

MS = mitral stenosis, MR = mitral regurgitation, CMV = closed mitral valvotomy, MVR = mitral valve replacement, HMVR = homograft mitral valve replacement, OMC = open mitral commissurotomy, DVR = double valve replacement, AR = aortic regurgitation.

Prosthetic valve thrombosis and infective endocarditis were the principal indications of reoperation following MVR. Other MV procedures performed were: OMC in 53 patients (mean interval 14.9 years) following previous CMV/OMC and MV repair in 14 patients (mean interval 4.4 years) following previous CMV/MV repair. There were 32 patients undergoing 3, and 2 patients undergoing 4 sternotomies. One patient underwent 5 sternotomies. Surgical technique Redo CMV The patient was placed in the right semi-lateral position. The operation was performed through the previous incision and the valve was approached through the left atrial wall. After an initial finger fracture technique, transventricular MV dilatation was performed. The MV status was assessed intraoperatively by transesophageal echocardiography (TEE). Open heart procedure following previous CMV Operations were performed through midsternotomy. After mid-sternotomy, the pericardial adhesions were carefully dissected to expose the

aorta, the right and left atria, and both vena cavae. With aortic and bicaval cannulation, cardiopulmonary bypass was established and the heart was dissected free of adhesions. The remaining procedure was performed in the usual fashion. Open heart procedure following previous open heart operations In all these patients, the groin was routinely cleaned and draped. Operations were generally performed through the median sternotomy incision using an oscillating saw. Care was taken to separate the heart from the back of the sternum. Pericardial adhesions were carefully released but only to the extent necessary for adequate exposure to establish cardiopulmonary bypass, after which the rest of the dissection to mobilize the heart was performed. All operations were performed with moderate general hypothermia (30◦ C to 32◦ C) and topical cooling by ice slush. Cardioplegic arrest was achieved by antegrade injection of cold-blood cardioplegia with St. Thomas’ solution. Cardioplegia was repeated at 20-minute intervals. The MV was debrided of all pannus and residual calcium. All previously placed pledgets and suture materials were removed. In case of previous repairs, on-table assessment was made for the feasibility

TABLE 4 Reoperation Following Previous Open Heart Surgery (Prior Valve Replacement) 1st Operation (N = 109) MVR (N = 92)

Indication for Reoperation Valve thrombosis Endocarditis Paravalvular leak

HMVR (N = 11) AVR (N = 3) DVR (N = 3)

Bioprosthetic degeneration Aortic valve disease MR MR Paravalvular leak

Type of Reoperation

No. of Patients

Mean Interval (years)

Mortality (Number)

Thrombectomy/MVR MVR DVR MVR MV resuture MVR AVR MVR DVR MVR MV resuture

54 9 1 5 8 11 4 11 3 2 1

2.2 2.4 3.2 1.3 4.8 9.8 8 2.8 5.1 1.5 0.6

8 2 0 1 1 0 0 0 0 0 0

MS = mitral stenosis, MR = mitral regurgitation, MVR = mitral valve replacement, HMVR = homograft mitral valve replacement, DVR = double valve replacement, AVR = aortic valve replacement, AR = aortic regurgitation.

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of retaining the native valve. Dysfunctional prostheses were excised. In a few cases of paravalvular leak MV resuture was successfully attempted. Mattress sutures of 2-0 Ethibond were used in all, pledgets were used sparingly. In patients with previously preserved chordae tendinae and papillary muscles, an attempt was made to represerve them when feasible. Temporary atrial and ventricular pacing wires were inserted in all patients. Attention was given to meticulous hemostasis and autologous blood was used in patients with hemoglobin >12 g%. The pericardium was approximated in all the patients at the end of the procedure. RESULTS All patients survived the reoperation. Aortic cannulation was possible in all but five patients in whom femoral artery cannulation was required (these five patients were operated elsewhere). Mortality Overall early mortality following reoperation was 5.64% (n = 42). Hemorrhage and low cardiac output were the major causes of mortality. All patients who died due to hemorrhage had undergone the primary surgery elsewhere (n = 10), where the pericardium had not been closed. Other complications included acute renal failure (n = 10), jaundice (n = 17), and wound infection (n = 27). Patients who underwent a primary as well as redo valve conserving procedure (CMV, OMC, and MV repair) had a mortality of 2.12% (2/94). In contrast, those patients who had a previous valve replacement had a significantly higher mortality of 11% (12/109) at the time of reoperation (p < 0.05). Mean follow-up period was 124.8 ± 30.5 months (range 2–300 months). Follow-up was 88.17%. There were no late deaths in the non-MVR group (redo CMV/MV Repair/OMC). One patient of redo CMV underwent MVR for restenosis after 9 years. One patient of redo OMC required MVR for valve failure (MS + MR) after 11 years. There were three episodes of thromboembolism in this group over a mean follow-up of 110 ± 26.6 months (0.3% per patient-year). In the valve replacement group (MVR/DVR), there were six late deaths; three due to valve thrombosis and pulmonary edema, one due to infective endocarditis, and two due to anticoagulant-related hemorrhage. There were 13 episodes of thromboembolism in this group over a mean follow-up of 120.4 ± 28.8 months (0.6% per patient-year). A total of 3.6% patients (n = 23) were readmitted with valve thrombosis, which was managed with thrombolysis. One patient required reoperation for the stuck valve. DISCUSSION Rheumatic heart disease is still prevalent in developing nations.2 It is a disease that predominantly affects the young in our country.3 Surgery is frequently required to provide symptomatic relief. These patients may return for reoperation for many reasons such as recurrent rheumatic activity, prosthetic valve dysfunction (thrombosis, paravalvular leak, and prosthetic

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valve endocarditis), degeneration of homograft or tissue valves, and failed repair. Reoperations are technically more difficult because of adhesions around the heart and the common association of pulmonary hypertension.4 Replacement operations are generally performed in a functionally compromised group of patients. These patients tolerate complications poorly.4 Reoperations for valvular heart disease are associated with a higher overall mortality than in the primary operation.1 Our observations suggest that the factors responsible for higher mortality are active infective endocarditis, higher preoperative NYHA class, and valve thrombosis. It has been reported that the early and late mortality in patients in NYHA classes I through III is significantly less than those patients who present in class IV.4-6 Patients more than 70 years old carry an increased risk for mortality.4-6 Women have a higher risk than men.4-6 Endocarditis, especially active infection, carries a high mortality.4-6 Earlier reoperation is often the key to success before severe cardiac exoskeletal damage occurs.4-6 Emergency surgery, previous thromboembolism, and advanced NYHA class have been found to be independent risk factors.7 Redo CMV is still favored in developing nations due to its cost effectiveness and avoidance of anticoagulation. Suri et al.8 reported hospital mortality of 2.8% in their series. We have so far had no early mortality in 28 patients of redo CMV for mitral restenosis. Fraser and Sugden9 suggested repeat CMV in selected noncalcific cases as a good means of palliation. They had a mortality of 10.4% compared with 4.2% for the primary operation. The mortality reported for redo MVR varies from 1.3% to 14.2%.10,11 The operative mortality after a second or third reoperation is significantly higher than that after primary operation or first reoperation.12 Our results were quite similar with a mortality of 4.5% after reoperations following previous CMV. We had a mortality of 1.4% (4/276) for primary OMC.13 We have also reported earlier a mortality of 4% (32/818) for primary MV repair14 and of 1.6% (4/240) for primary MVR.15 In contrast, the mortality was 8.6%, for reoperation following previous open heart MV surgery. Preservation of the chordae tendinae and papillary muscles is now a standard procedure during MVR.16 Its effect on early and late left ventricular function is well proven.16 Rao et al.16 believe that represervation of chordae is technically feasible and may improve the outcome after MVR. The adverse effect of tricuspid valve disease is known.17 Additional morbidity is imposed due to low cardiac output, poor right ventricular function, and associated tricuspid valve disease. Many surgeons now recommend redo MV surgery via right thoracotomy.18 They report reduced blood loss and a decreased requirement of ionotropic support.18 The right thoracotomy approach minimizes dissection of adhesions, avoids injury to the right ventricle, and prevents injury to coronary bypass grafts.18 In our experience, however, median sternotomy was safe for reentry into chest in all except five patients. The use of oscillating saw and careful lysis of pericardial

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adhesions has been responsible for the good results. Some authors describe reoperations without mobilizing the heart from the pericardium by opening the pleural cavities.19 However, we believe that mobilization is essential for adequate exposure, proper myocardial protection, and complete de-airing. Tsai et al.20 reported their preliminary experience with video-assisted reoperative MV surgery. They felt this approach was technically feasible even in redo MV surgery, but more experience is needed. Few authors suggest routine exposure of femoral vessels prior to sternotomy for repeat open heart procedures.4 This allows emergency institution of cardiopulmonary bypass in case of catastrophic hemorrhage during redo sternotomy. Cohn et al.4 also advocate liberal use of femorofemoral bypass with thin-walled venous tubing. We have not experienced any difficulty and prefer to keep only the groin area ready for dissection. In all the five patients in whom this complication occurred, cardiopulmonary bypass could be established quickly with no untoward effects. In all the primary operations we routinely close the pericardium either completely or partially. We believe that this was the most important step in reducing complications and mortality at reoperations. CONCLUSION Redo MV surgery is safe and can be undertaken with acceptable mortality and morbidity. With advances in cardiopulmonary bypass methods, operative techniques, and myocardial preservation there has been a definite trend toward neutralization of risk between primary and redo surgery. However, for optimal results, myocardial damage should be prevented—by adequate preoperative medical therapy and prompt reoperation when necessary. REFERENCES 1. Blackstone EH, Kirklin JW: Death and other time related events after valve replacement. Circulation 1985;72(4):753-767. 2. Padmavati S: Present status of rheumatic fever and rheumatic heart disease in India. Indian Heart J 1995;47:395-398. 3. Mishra TK, Rath PK, Mohanty NK, et al: Juvenile chronic RHD: One decade long experience. Indian Heart J 1999;51:653 (Abstract).

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4. Cohn LH, Aranki SF, Rizzo RJ, et al: Decrease in operative risk of reoperative valve surgery. Ann Thorac Surg 1993;56:15-21. 5. Cohn LH, Koster JK, Vandevanter S, et al: The in-hospital risk of re-replacement of dysfunctional mitral and aortic valves. Circulation 1982;66(Suppl 1):153-156. 6. Husebye DG, Pluth JR, Piehler JM, et al: Reoperation on prosthetic heart valves. An analysis of risk factors in 552 patients. J Thorac Cardiovasc Surg 1983;86:543-552. 7. Pansini S, Ottino G, Forsennati PG, et al: Reoperations on heart valve prosthesis: An analysis of operative risks and late results. Ann Thorac Surg 1990;50:590-596. 8. Suri RK, Pathania R, Jha NK, et al: Closed mitral valvotomy for mitral restenosis: Experience in 113 consecutive cases. J Thorac Cardiovasc Surg 1996;112:727730. 9. Fraser K, Sugden BA: Second closed mitral valvotomy for recurrent mitral stenosis. Thorax 1977;32:759-762. 10. Gill IS, Masters RG, Pipe AL, et al: Determinants of hospital survival following reoperative single valve replacement. Can J Cardiol 1999;15(11):1207-1210. 11. Piehler JM, Blackstone EH, Bailey KR, et al: Reoperation on prosthetic heart valves. Patient specific estimates of in-hospital events. J Thorac Cardiovasc Surg 1995;109(1):30-48. 12. Ataka K, Okda M, Yamashita C, et al: Valvular heart disease. A comparative study of results after primary operation, reoperation, and after multiple reoperation. Jpn J Thorac Cardiovasc Surg 1999;47(8):377-382. 13. Choudhary SK, Dhareshwar J, Govil A, et al: Open mitral commissurotomy in current era: Indications, technique and results. Ann Thorac Surg 2003;75:41-46. 14. Choudhary SK, Talwar S, Dubey B, et al: Mitral valve repair in a predominantly rheumatic population. Long term results. Tex Heart Inst J 2001;28(1):8-15. 15. Wasir H, Choudhary SK, Airan B, et al: Mitral valve replacement with chordal preservation in a rheumatic population. J Heart Valve Dis 2001;10(1):84-89. 16. Rao V, Komeda M, Weisel RD, et al: Results of represervation of the chordae tendinae during redo mitral valve replacement. Ann Thorac Surg 1996;62:179-183. 17. Hornick P, Harris PA, Taylor KM: Tricuspid valve replacement subsequent to previous open heart surgery. J Heart Valve Dis 1996;5(1):20-25. 18. Holman WL, Goldberg SP, Lesley JE, et al: Right thoracotomy for mitral reoperation: Analysis of technique and outcome. Ann Thorac Surg 2000;70:1970-1974. 19. Yano Y, Hayase S, Ogawa K, et al: Repeated valvular surgery with minimal heart dissection. Kyobu Geka 1994;47(8):650-654. 20. Tsai FC, Lin PJ, Chang CH, et al: Video assisted cardiac surgery: Preliminary experience in reoperative mitral valve surgery. Chest 1996;110:1603-1607.