Circulation: Operating risk lowers for PMR after MI

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Prompt diagnosis and aggressive therapeutic approach is important for patients incurring papillary muscle rupture (PMR) after acute MI, according to a study published online Sept. 22 in Circulation.

PMR is an infrequent but catastrophic complication of acute MI, according to Antonio Russo MD, and colleagues from the divisions of cardiovascular diseases and internal medicine, biostatistics and cardiovascular surgery at the Mayo Clinic in Rochester, Minn. Although always considered, surgical treatment is often denied because of high operative mortality. Moreover, the authors noted that the effects of surgery for PMR on long-term outcome, particularly compared with expected outcome after MI, are undefined.

The researchers evaluated 54 consecutive patients (age, 70 years; 74 percent male), who underwent mitral surgery for post-MI PMR from January 1980 through December 2000. They noted severe presentation (cardiogenic shock, pulmonary edema or cardiac arrest) in 91 percent preoperatively. Performance of coronary artery bypass graft was associated with lower operative mortality, whereas there was a trend for lower mortality after surgery after 1990.

The investigators said that the operative mortality (overall, 18.5 percent) decreased from 67 percent up to 1990 without coronary artery bypass graft to 8.7 percent after 1990 with CABG.

Russo and colleagues also found that the overall five-year survival was 65 percent, and survival free of congestive heart failure was 52 percent; five-year survival of 30-day operative survivors was 79 percent, identical to that of matched controls with MI (similar age, sex, ejection fraction, MI location and MI year). Survival free of congestive heart failure was similar in PMR cases and MI controls (10-year survival, 28 vs. 36 percent.

Based on their findings, the authors concluded that surgery for post-MI PMR involves a notable operative mortality, but there are recent trends for lower operative risk, particularly with associated CABG. Long-term after surgery, outcome is restored to that of similar MI without PMR.