Usefulness of Coronary Flow Reserve Immediately After Primary Coronary Angioplasty for Acute Myocardial Infarction in Predicting Long-Term Adverse Cardiac Events

Coronary flow reserve (CFR) evaluated immediately after reperfusion is thought to reflect the degree of microvascular injury and predict left ventricular (LV) functional recovery after acute myocardial infarction. It was hypothesized that CFR immediately after reperfusion would be predictive of the occurrence of long-term adverse cardiac events. Using a Doppler guidewire, CFR was evaluated immediately after primary coronary angioplasty in 118 consecutive patients with first anterior acute myocardial infarctions. Adverse cardiac events combining cardiac death, recurrent myocardial infarction, and congestive heart failure were recorded during an average follow-up period of 62 ± 32 months. Using receiver-operating characteristic analysis, CFR ≤1.3 was the best predictor of future cardiac events (sensitivity 86%, specificity 70%). Accordingly, patients were divided into 2 groups: those with CFR ≤1.3 (n = 50) and those with CFR >1.3 (n = 68). Patients with CFR ≤1.3 had significantly higher peak creatine kinase concentrations, lower LV ejection fractions, and higher LV volumes compared with patients with CFR >1.3. CFR was significantly correlated with the LV ejection fraction at 4 weeks (r = 0.50, p <0.0001) and LV end-diastolic volume at 4 weeks (r = −0.43, p <0.0001). Kaplan-Meier survival analysis showed a higher incidence of adverse cardiac events in patients with CFR ≤1.3 (p <0.0001). In conclusion, CFR evaluated immediately after primary coronary angioplasty is a strong predictor of long-term adverse cardiac events after reperfused acute myocardial infarction.