Clinical outcome after mitral valve surgery due to ischemic papillary muscle rupture

Objectives: The aim of the study was to determine preoperative and postoperative predictors of mortality in patients with severe mitral regurgitation (MR) undergoing mitral valve operations for papillary muscle rupture following myocardial infarction.

Methods: We retrospectively analysed 28 patients who underwent mitral valve (MV) surgery for ischemic papillary muscle rupture. The diagnosis of the MR was based on echocardiography and left ventricular angiography.

Results: 28 patients underwent MVR or MVr. Mean age was 63.4±9.0 years, 22 patients were male (78.6%). The in-hospital mortality was 39.3% (11/28). There were no significant difference in the baseline characteristics between survivors and non-survivors. Concomitant CABG was performed in 66.7% in the survivor group and in 61.5% in the non-survivor group (p=0.245). Significant postoperative predictors of mortality included low cardiac output (LCO, p=0.05), renal failure with hemodialysis (p=0.005) and implementation of extracorporal membrane oxygenation therapy (ECMO, p=0.005). The time between myocardial infarction and time of surgery showed no significant effects on survival. A multivariate analysis was performed to identify risk factors for death and revealed patient age (OR 4.2), body mass index >30 (OR 2.9), high urgent priority (OR 2.75) and myocardial infarction within the last 48 hours (OR 2.67) as possibly independent preoperative risk factors. Risk factors for the postoperative course were LCO (OR 5.0), necessity of intraaortic balloon pump treatment (OR 7.58), ECMO therapy (OR 5.57) and renal failure with hemodialysis (OR 15.13). Additional risk factors were an operative time more than 300min (OR 4.2), cardiopulmonary bypass for more than 200min (OR 4.2) and MVr (OR 1.95).

Conclusion: Papillary muscle rupture in case of myocardial infarction with severe MR carries a high operative mortality. The long term outcome for the surviving patients is comparable to patients with uncomplicated mitral valve surgery. Additional CABG does not influence the acute postoperative course, but may improve the long-term survival. Surgical treatment within 48 hours after MI may increase mortality, but expeditious diagnosis and treatment is important to avoid heart failure and LCO. Postoperative development of LCO with necessity of ECMO therapy and renal failure with hemodialysis substantially reduces survival.