Aortic valve allografts for mitral valve replacement.

Between May, 1967, and April, 1971, 122 patients underwent mitral valve replacement with fresh aortic valve allografts mounted on rigid support rings. The operative mortality rate was 6.6 percent. Current evaluation was obtained on all patients; the average postoperative follow-up interval for surviving patients is 4.8 years (range, 3.3 to 7.1). Survival rates 1, 2, and 5 years after mitral valve replacement are 89, 86, and 71 percent, respectively. The average functional class of 90 current survivors is 1.6, as compared to 2.9 preoperatively. Thirty-six thromboembolic episodes have occurred in 28 patients, generating a thromboembolism rate of 7 percent per patient year of analysis. Allograft valve dysfunction has occurred in 64 patients, requiring reoperation in 16 and causing death in two. The linearized valve dysfunction rate is 13 percent per patient year. Pathological examination of recovered allograft valves revealed predominantly leaflet fibrosis and calcification, acellular collagenous valve matrix, and infiltration with chronic inflammatory cells. The results of this long-term analysis indicate that mitral valve replacement with fresh aortic allografts provides significant functional improvement and an acceptably low rate of thromboembolism. However, the time-related rate of allograft valve dysfunction is unacceptably high and does not justify further clinical use of this type of bioprosthesis.     

Chylopericardium following mitral valve replacement.

A 49-year-old man with mitral regurgitation developed chylopericardium after mitral valve replacement. On postoperative day (POD) 1, the patient was started on a regular diet. On POD 2, drainage from retrosternal and intrapericardial tubes increased, becoming turbid and milky. Because the triglyceride concentration was high at 197 mg/dl, we diagnosed the condition as chylopericardium. The patient was given nothing by mouth for 2 days and, from POD 4, received a low-fat diet, after which drainage cleared and volume decreased. The 2 drainage tubes were removed on POD 6, and he was discharged without complications on POD 18.     

Risk of repeat mitral valve replacement for failed mitral valve prostheses

Background

Advances in tissue prosthetic valve design and manufacturing have stimulated renewed interest in the use of biological valves in younger patients. This approach, however, risks reoperation. We therefore reviewed our recent experience with repeat mitral valve replacement to better define its contemporary risks.

Methods

Using a computerized database, we identified and compared 106 patients undergoing repeat mitral valve replacement with 562 control patients undergoing primary mitral valve replacement between January 1993 and December 2000 at our institution.

Results

There were no significant differences between repeat and primary surgery groups with respect to age (mean 66 ± 12 vs 64 ± 13 years), gender distribution (women 65% vs 64%), preoperative functional class, ejection fraction, or active endocarditis (6.6% vs 3.4%). The indication for reoperation in the repeat group was structural dysfunction in 49 patients (46%), paravalvular leak in 21 patients (20%), nonstructural dysfunction in 11 patients (10%), and progression of other native valve disease in 8 patients (8%). Prior prostheses were mechanical in 46 patients (43%). Mean time to reoperation was 11.5 ± 7.1 years. There were 5 deaths out of 106 patients in the repeat group (4.7%) and there were 23 deaths out of 562 patients in the control group (4.1%) (p = NS). Multivariate analysis identified prior myocardial infarction (p = 0.014, odds ratio 2.9) and nonelective surgical status (p = 0.004, odds ratio 2.3) as significant predictors of operative mortality.

Conclusions

The risk of repeat mitral valve replacement was low suggesting that there should be less reluctance to recommend patients choose a bioprosthesis over a mechanical prosthesis. Given the expected durability of current designs, bioprosthetic use may be explored in younger patients without subjecting those individuals to excessive risk.     

Anaesthetic management for mitral valve replacement

Anaesthetic management for mitral valve replacement in 138 patients is presented. Value of preoperative visits, control of haemodynamic status, cheerful operative surroundings and smooth induction is stressed. Haemodilution technique, effective myocardial preservation and modern monitoring facilities help to maintain the patients near-normal physiological status during the procedure. In patients with unstable cardiovascular status, postoperative overnight ventilation is advocated, which maintains better oxygenation, acid-base values and reduces the work of breathing. Management of patients by anaesthesiologists and surgeons as a team reduces the mortality and morbidity significantly.     

Cardiac autotransplantation for mitral valve replacement

We present an unusual case of a 69-year-old patient with severe mitral valve regurgitation and extensive coronary artery disease who required mitral valve replacement and myocardial revascularization. With the patient on cardiopulmonary bypass, distal vein grafting was performed first. This procedure was followed by a transatrial transseptal approach to the mitral valve, but visualization of valve structures was extremely difficult. Following the partial excision of the posterior leaflet and the placement of a few pledgeted annular sutures on which traction was applied, access to the mitral annulus remained impossible. There appeared no option but to explant the heart and perform the mitral valve replacement ex vivo. Cardiac explantation was performed by transecting the aorta and pulmonary artery and completing the already extended right and left atriotomies. Cold blood cardioplegic solution was administered intermittently into the coronary sinus during the period when the heart was ex vivo. A porcine bioprosthesis was easily seated into the mitral annulus. Cardiac reimplantation consisted of repair of the previously divided atria, and end-to-end anastomoses of both the aorta and the pulmonary artery. While rewarming was taking place, the 3 proximal vein graft anastomoses were performed. Temporary and permanent epicardial pacing leads were placed. Total ischemic time was 299 minutes, and the period on cardiopulmonary bypass was 359 minutes. The heart sustained good hemodynamics, and after full functional recovery, the patient was discharged home and remained well for 7 years. In view of this experience, a questionnaire was mailed to >3000 cardiothoracic surgeons, and responses were obtained from 1120. Inadequate mitral valve exposure had been experienced by 70%. To provide increased exposure, 50% had extended the initial atrial incision both horizontally and perpendicular to the atrial groove, 17% had divided the superior vena cava, 1% had divided the inferior vena cava, and 1% had divided both cavae. Furthermore, 4% of surgeons reported being forced to abandon the operation in 71 patients because of inadequate exposure. Three hundred twenty perioperative deaths were directly attributed to an incomplete surgical procedure. Explantation of the heart, with mitral valve replacement being performed ex vivo followed by reimplantation, should be considered when access to the mitral valve proves impossible with more standard techniques.     

Improved mitral valve replacement

We describe a simple, reproducible technique of achieving more normal left ventricular function after mitral valve replacement. Polytetrafluoroethylene (PTFE) sutures are used as chordae tendineae to restore the integrity between the mechanical valve and papillary muscles and thus the left ventricular wall.     

Transaortic mitral valve replacement

A 34-year follow-up is described after a Konno aortoventriculoplasty to correct a restricted aortic annulus and a recurrent aortic prosthetic valve endocarditis with subannular and interventricular abscesses.     

Early results of mitral valve replacement.

Early results of mitral valve replacement were reviewed in 336 unselected patients, 261 without and 75 with concomitant coronary artery bypass grafting (MVR and MVR + CABG groups). Early (less than 30 days) mortality was 7% in the MVR and 16% in the MVR + CABG group, with cardiac failure as the dominant cause. In multivariate analysis, the variables most strongly related to early mortality were congestive heart failure, diabetes and previous cardiac surgery in the MVR group and congestive heart failure in MVR + CABG. In the cases with fatal outcome the incidence of peroperative technical complications was 32% at MVR and 17% at MVR + CABG. The incidence of myocardial injury was 21% and 35% in the respective groups, and the early mortality in these cases was 19% vs 23%. Half of all fatal cases showed signs of peroperative myocardial injury. Multivariate analysis showed factors independently related to myocardial injury to be year of surgery and aortic cross-clamp time in MVR and previous cardiac surgery in MVR + CABG. Operation before cardiac reserves are reduced, optimal peroperative myocardial preservation and avoidance of technical errors should improve results of MVR.     

Modified continuous suture technique for mitral valve replacement.

A modified continuous suture technique for mitral valve replacement is described which retains desirable features of the less expedient interrupted suture technique. An initial experience with this technique in more than 300 patients has encouraged its continued use.     

Economic impact of mitral valve plasty versus replacement for mitral valve insufficiency

AIM: The principal techniques for surgical correction of mitral valve regurgitation (MR) were compared, with emphasis on the economic impact. METHODS: In a prospective non-randomized study 225 patients undergoing mitral valve repair were analyzed, 75 had mitral valve plasty (MVP) and 150 had mitral valve replacement (MVR). Patient demographics showed no group differences. RESULTS: Cardiopulmonary bypass time and ischemia time were shorter in the MVP-group, p<0.0001. Hospital mortality was lower after MVP, 2.0% (3/150) compared to MVR, 6.7% (5/75). ICU-stay was shorter in the MVP-group and so was length of postoperative hospital stay, p=0.014. Urgent operation was the only significant risk factor for mortality after MVP. Re-operation, endocarditis, grade IV MR, and NYHA class IV were additional risk factors in the MVR-group. Postoperative improvements of NYHA and mitral valve function were similar in both groups. MVP was more cost effective than MVR (18,050 USD or 20,430 Euro versus 24,824 USD or 28,097 Euro, p<0.001). CONCLUSION: Mitral valve plasty for MR is efficient and associated with shorter CPB and ischemia times as well as length of stay in ICU, together with a lower device cost, which makes MVP more cost effective than MVR.     

Twelve-year experience with mitral valve replacement.

Between 1962 and 1974, 203 mitral prostheses were implanted in 201 patients. Of the 102 survivors, 29 have Beall, 25 Kay-Shiley, 22 Starr-Edwards (SE) 6000, and 27 SE 6320 valves. Full rehabilitation was achieved in 25 patients with Beall and 23 with SE 6320 valves. Sixteen with SE 6000 valves remain normally active. Only 8 with Kay-Shiley prostheses have resumed normal activities. Systemic embolization occurred with the following frequencies per 1,000 patient-months: 13.7 for those receiving the Kay-Shiley valve; 7.2 in the SE 6000 group; 4.3 after SE 6320 implantations; and 3;1 for the Beall group. Other prosthesis-related complications that were much less frequent included detachment (10), bacterial endocarditis (5), and hemolysis (10). Three Kay-Shiley valves malfunctioned. Life table analyses reveal the following survival rates: 33% after 11 years in the SE 6000 patients, 50% after 7.5 years in the Kay-Shiley group, 69% 2.5 years after SE 6320 implantation, and 65% 3.5 years after replacement with a Beall valve. Evidence is presented to support the extension of operative treatment to patients with less advanced valvular heart disease. Postoperative anticoagulation remains an unresolved issue despite lower rates of thromboembolism. More cumulative analyses of survival and morbidity and follow-up hemodynamic data are needed to assess the Beall and SE 6320 prostheses now employed in our valve replacement program.     

Generation of chordae tendineae with polytetrafluoroethylene stents. Results of mitral valve chordal replacement in sheep

Surgical repair of ruptured or elongated chordae tendineae of the mitral valve is one of the most complex reconstructive techniques in cardiac surgery. Various surgical procedures have been described to repair chordal abnormalities of the anterior leaflet of the mitral valve with unpredictable results. Mitral valve replacement is usually recommended in that situation. This report describes a simple repair technique that we have devised. We resected one or two marginal chordae of the anterior leaflet of the mitral valve in 35 sheep and replaced them with a double-armed, pledget-supported, expanded polytetrafluoroethylene suture. The 30 surviving animals were studied hemodynamically and were electively put to death 3, 6, 9, 18, and 24 months after the operation. Mitral insufficiency did not develop in any of the sheep. All specimens had a normal mitral valve without thrombosis. The polytetrafluoroethylene suture remained pliable and was incorporated into the anterior leaflet and papillary muscle. Scanning and transmission electron microscopy showed that the suture was completely covered by a sheath of tissue with a collagen structure remarkably similar to that of a native chorda. Calcification was not detected in the new chordae. This reproducible and safe technique may considerably simplify the difficult repair of chordal abnormalities.     

Risks of mitral valve replacement and mitral valve replacement with coronary artery bypass

One hundred thirty consecutive patients who underwent mitral valve replacement (MVR) or MVR with coronary artery bypass grafting (CABG) using cold crystalloid cardioplegic solution were analyzed to determine operative mortality and risk factors. Twenty-eight patients had mitral stenosis (MS), 37 had mitral regurgitation (MR), 37 had mixed MS and MR, 23 had MR with coronary artery disease (CAD), and 5 had MS with CAD. Preoperative pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac index were not different among groups, but patients with MR and CAD had a significantly higher left ventricular end-diastolic pressure (LVEDP) and a significantly lower ejection fraction than other groups. Mortality was 7.1% for patients with MS, 5.4% for MR, 8.1% for mixed MS and MR, 0 for MS with CAD, and 21.7% for MR and CAD. Overall mortality was 9.2%. Eleven patients had emergency operations for cardiogenic shock with a mortality of 45%. Nineteen additional patients in New York Heart Association (NYHA) Functional Class IV had MVR or MVR plus CABG with a mortality of 26%. Sixteen patients required intraaortic balloon pump assistance, and 9 survived. Four patients with MR and CAD required the left ventricular assist device, and 3 survived. Excluding patients who had emergency operations, overall mortality was 5.8%. Excluding patients who had emergency operations and patients in NYHA Functional Class IV, overall mortality was 2%. Factors associated with death were cardiogenic shock, NYHA Class IV, LVEDP greater than 15 mm Hg (16% mortality), and age greater than 60 years (15% mortality).