The effect of preservation of chordae tendineae on mitral valve replacement for postinfarction mitral regurgitation.

Fifty-one consecutive patients underwent mitral valve replacement for mitral regurgitation secondary to myocardial infarction. Fifteen patients were in cardiogenic shock when operated on, 22 were in NYHA functional class IV, and 14 were in class III. Mitral valve replacement with preservation of the chordae tendineae and papillary muscles was performed in 10 patients in cardiogenic shock and 22 patients who had elective surgery. Concomitant procedures included repair of left ventricular aneurysm in nine, tricuspid valve repair in three, aortic valve repair or replacement in four, and aortocoronary bypass in 44 patients. Twenty-six clinical, hemodynamic, angiographic, and operative variables were analyzed for statistical significance (univariate analysis) and then entered into a logistic regression analysis with operative and late mortality as end points. There were four operative deaths (8%). Only preoperative cardiogenic shock and mitral valve replacement with complete excision of the native valve were predictive of operative mortality. Actuarial survival at 4 years was 89 +/- 9% for patients with preserved chordae tendineae and 59 +/- 11% for patients with completely excised mitral valves. Only complete excision of the mitral valve and ejection fraction lower than 35% were predictive of late mortality. These data suggest that, although the papillary muscles are diseased in patients with mitral regurgitation secondary to myocardial infarction, it is important to preserve them and their chordae tendineae during mitral valve replacement.