Mild Functional Ischemic Mitral Regurgitation Following Acute Coronary Syndrome: A Retrospective Study

BACKGROUND: Ischemic mitral regurgitation is a frequent complication of acute coronary syndrome. It primarily occurs in patients with a prior myocardial infarction but also may be seen with acute ischemia, a setting in which the MR typically resolves after the ischemia resolves. The vast majority of patients have “functional” ischemic MR. In these individuals, the papillary muscles, chordae, and valve leaflets are normal. However, the leaflets do not coapt and restricted leaflet motion is frequently noted on echocardiography. Ischemic mitral regurgitation indicates a poor prognosis after acute myocardial infarction. This study addresses the clinical characteristics of patients of acute coronary syndrome with mild functional ischemic mitral regurgitation and its impact on immediate in-hospital cardiovascular outcomes and death. PATIENTS AND METHODS: From March 2006 through May 2007, patients who underwent 2-dimensional (2D) color doppler echocardiographic quantification of ischemic mitral regurgitation within 10 days of admission for acute coronary syndrome (ACS) in Manipal Teaching Hospital, a tertiary hospital in the western region of Nepal were noted. The demographic details, conventional risk factors of coronary artery disease, clinical and laboratory findings, treatment course and in-hospital outcomes of all the patients with mild functional ischemic MR following ACS in that time duration were recorded in a designated Performa. A total of 94 patients enrolled in the study were divided into two groups: Group I with mild functional ischemic MR and Group II without MR on 2D echocardigraphic assessment. Patient characteristics, risk factors, ejection fraction, and cardiovascular outcome and death among the two groups were compared and analyzed using software package SPSS 17.0 version. RESULTS: Group I constituted 64.89% of the study population and Group II comprised of 35.11%. The patients in Group I was more likely to be elderly diabetic (P<0.05), and smokers with hypertension (P < 0.05). Mild functional ischemic MR was more common in patients with STEMI as compared to those with unstable angina and NSTEMI (55.7%, 36.1%, and 8.2%; P < 0.05).The mean ejection fraction in the first group was 54.84% in contrast to 58.92% observed in group II (P < 0.05).The type of wall involvement inferred from EKG analysis was homogeneously distributed in both the groups. Finally, there was no difference in immediate in-hospital (within 10 days) mortality or cardiovascular outcomes (heart failure, ventricular tachycardia/fibrillation, hypotension, and cardiogenic shock) between these two groups. CONCLUSION: Ischemic mitral regurgitation following acute coronary syndromeare more likely in elderly diabetics and hypertensive smokers. It is a more common finding in STEMI. Although mild MR following ACS does reduce ejection fraction, the immediate (within 10 days) in-hospital mortality and cardiovascular outcomes are not significantly altered.