Severe mitral regurgitation complicating acute myocardial infarction. Clinical and angiographic differences between patients with and without papillary muscle rupture.

AIMS

To assess the differential clinical and angiographic characteristics of patients with severe mitral regurgitation related (n = 31) or unrelated (n = 16) to papillary muscle rupture complicating acute myocardial infarction.

METHODS AND RESULTS

The clinical and angiographic features of patients with myocardial infarction and severe mitral regurgitation were evaluated. Patients with papillary muscle rupture were older (67 vs 60 years, P < 0.005) and had a lower rate of diabetes (7% vs 38%, P < 0.005) and of previous angina or infarction (24% vs 50%, P < 0.05). Frequency of inferior infarction was high and comparable in both groups (papillary muscle rupture, 72% vs non-papillary muscle rupture, 88%, ns) whereas in-hospital rate of angina/infarct extension prior to mitral regurgitation, also high, tended to be higher in patients without than in those with papillary muscle rupture (67% vs 39%, ns). Incidence of multivessel disease tended to be higher in patients without papillary muscle rupture (87% vs 56%, P < 0.06) and they had a lower ejection fraction (46 +/- 15 vs 61 +/- 14%, P < 0.03), whereas the culprit artery was mainly the right or the circumflex coronary artery in both groups (papillary muscle rupture, 100% vs non papillary muscle rupture, 93%, ns). Valve replacement was performed earlier in patients with papillary muscle rupture (1 (1; 14) vs 25 (5; 45) days, median, P < 0.002) but was associated with a similar mortality (papillary muscle rupture 11/24, 46% vs non-papillary muscle rupture, 7/15, 47%, ns). The main cause of death was cardiogenic shock in patients without papillary muscle rupture (5/7, 71%), and respiratory insufficiency--sepsis in those with papillary muscle rupture (7/11, 64%).

CONCLUSIONS

Severe mitral regurgitation in myocardial infarction with or without papillary muscle rupture is mostly related to inferior infarction and often follows reinfarction, particularly in non-papillary muscle rupture cases. The main contributors to surgical mortality appear to be respiratory insufficiency in patients with papillary muscle rupture and cardiogenic shock, facilitated by a lower ejection fraction, a higher frequency of diabetes and more extensive coronary disease, in patients without papillary muscle rupture.