Coronary Flow Reserve as a Predictor of Long-Term Clinical Outcome after Acute Myocardial Infarction

ABSTRACT

BACKGROUND AND OBJECTIVES: It has been shown that the coronary flow reserve (CFR) of an infarct related artery can predict left ventricular functional recovery following acute myocardial infarction (AMI). However, the prognostic value of CFR on the long-term clinical outcome of patients with an AMI has not been studied. SUBJECTS AND METHODS: Using a Doppler guide wire, we measured the CFR in 130 patients with an AMI following successful intervention (6+/-3 days after onset of the AMI). Two-year follow-up was conducted with regard to end points, including cardiac death, non-fatal AMI, and severe congestive heart failure (CHF; > or = NYHA III). RESULTS: During the follow-ups, cardiac events occurred in 17 patients (5 deaths, 3 non-fatal AMIs and 9 severe CHFs). After analysis of the receiver operating characteristic curves, the best cut-off value for CFR in predicting cardiac events was 1.4 (sensitivity 76.5%, specificity 73.5%, accuracy 82.0%). With cardiac events as an end point, a 2-year Kaplan-Meier event survival analysis revealed that the patients with a CFR 1.4 (Event free survival rates were 69.8% vs. 95.4%, respectively, p<0.001). Using Cox proportional hazard analyses, as an independent predictor, age, heart rate, CFR and left ventricular end systolic volume index, were also found to be significantly associated with cardiac events (hazard ratios 1.1224, 1.0404, 0.1887, and 1.0588, respectively). CONCLUSION: The coronary flow reserve, of infarct related arteries, measured during the early recovery phase can be used as an independent predictor for the prognosis of patients with an acute myocardial infarction following successful intervention.