Pitfalls in surgical decision-making during mitral valve repair

Mitral valve annuloplasty with a bovine pericardial strip--18-year results

PURPOSE

Prosthetic annuloplasty rings are currently used in mitral reconstruction. Posterior annuloplasty with a bovine pericardial strip is a technique largely used in the Heart Institute of University of São Paulo Medical School. The purpose of the study was to analyze the late results of mitral valve repair with posterior annuloplasty using a bovine pericardial strip.

METHODS

Between January 1984 and December 2002, 273 patients underwent mitral valve repair with posterior pericardial annuloplasty in the Heart Institute of University of São Paulo Medical School. One hundred and forty four (52.7%) were women and ages ranged between 1 and 76 years (38.3 +/- 21.1). Rheumatic fever was present in 52.0% of the patients. Associated techniques were employed in 26.0% of the patients, and the most frequent was chordal shortening (9.2%).

RESULTS

Hospital mortality was 3.3% (9 patients), with the major cause being low cardiac output (6 patients). Actuarial survival was 55.1% +/- 16.8% in 18 years. During the 18-year follow-up: patients were free from the following: reoperation (59.1% +/- 13.9%, (percent +/- Standard Error), thromboembolism (97.4% +/- 2.3%), hemolysis (99.2% +/- 0.2%), and endocarditis (99.6% +/- 1.0%). In the late follow-up period, 83.9% were classified as New York Heart Association functional class I.

CONCLUSIONS

Late results with mitral valve repair with posterior annuloplasty using a bovine pericardial strip were satisfactory. The technique is feasible, reproducible, and cost effective.

[Mitral valve repair versus mitral valve replacement]

Over the past 40 years mitral valve surgery has changed dramatically. After initial enthusiasm with the introduction of valve prostheses in the 1960s, a renewed interest in repair techniques began in the 1970s with the introduction of annuloplasty rings. These repair techniques revealed that the integrity of the subvalvular apparatus plays an important role in left ventricular function. When considering the major series comparing early and late results of mitral valve repair versus prosthetic mitral valve replacement, operative mortality rate is lower for patients with mitral valve repair. Long-term results also show a superior survival rate after mitral valve reconstruction. In addition, several problems can occur with the prosthetic valve, such as thromboembolism and endocarditis. All of these factors favor valve repair over replacement. The success of mitral valve repair depends on many factors: etiology of the mitral valve disease and the resultant pathomorphology of the valve, patient's circumstances such as age or contraindication for anticoagulation, and the experience of the surgeon. The decision whether to repair or replace the mitral valve depends on these factors. Data in the literature and in large collective databases reflect the advantages of mitral valve repair, with over 75 % of current mitral valve surgeries being repairs.In the past 5 years the exposure of the mitral valve through a right lateral minithoracotomy using video assistance has developed into a widespread technique. This approach allows complex mitral valve repair as well as mitral valve replacement even with biological stentless prostheses, with decreased morbidity. The addition of radiofrequency ablation for restoration of sinus rhythm enhances the outcome after mitral valve surgery, and can also be easily performed through a minithoracotomy technique.