Mitral regurgitation in patients with coronary artery disease and low left ventricular ejection fractions. How should it be treated?

In recent years, coronary artery bypass grafting has been extended to include patients with very low left ventricular ejection fractions. Should concomitant mitral valve regurgitation be corrected simultaneously? Between January 1990 and July 1994, 43 patients with preoperative left ventricular ejection fractions < or = 25% and echocardiographic evidence of concomitant mitral valve regurgitation (grade I, 18 patients; II, 19 patients; and III, 6 patients) underwent primary coronary artery bypass grafting. None of these patients underwent simultaneous mitral valve surgery. Twenty-four patients (56%) had pulmonary artery pressures > or = 40 mmHg (pulmonary hypertension). The mean preoperative left ventricular ejection fraction was 18.7% +/- 4.4% (range, 10% to 25%), and the mean pulmonary artery pressure was 45.6 +/- 15.8 mmHg. The average of number of grafts per patient was 4.5 +/- 1.5. Five patients underwent simultaneous repair of a left ventricular aneurysm. The hospital mortality rate was 4.7% (2/43). Transient low cardiac output occurred postoperatively in 13 patients (30%). Sixteen patients (37%) had no postoperative complications. The average follow-up of the 41 hospital survivors was 6 months (range, 1 to 32 months). One patient died 8 months after surgery for an overall mortality rate of 7%. Another 2 patients had graft occlusions that did not require reoperation. In the 40 surviving patients, follow-up echocardiography revealed that 37 patients (93%) had either no mitral valve regurgitation or only very mild mitral valve regurgitation (grade I). Three patients had grade II mitral valve regurgitation, but none required mitral valve surgery. The New York Heart Association functional class improved significantly in all hospital survivors (from 3.4 +/- 0.6 to 1.7 +/- 0.7; p > 0.001), and left ventricular ejection fractions rose from 19.0% +/- 4.6% to 42.0% +/- 8.3%. Coronary artery bypass grafting is possible in patients with very low left ventricular ejection fractions who present with 2- or 3-vessel disease, significant coronary artery stenoses (less than or equal 70%), and angina. The mortality rate is acceptable and morbidity is low. If there is no rupture of papillary muscle or chordae, concomitant ischemic mitral regurgitation (grades I through III) seems to return to normal after coronary artery bypass grafting and, therefore, does not need to be corrected surgically during the primary operation.