Non-invasive coronary flow reserve after successful primary angioplasty for acute anterior myocardial infarction is an independent predictor of left ventricular recovery and in-hospital cardiac events.

BACKGROUND

The prediction of left ventricular (LV) recovery and adverse cardiac events after reperfused acute myocardial infarction (AMI) is challenging. The aim of this study was to assess the usefulness of noninvasive coronary flow reserve (CFR) to predict LV recovery and in-hospital adverse cardiac events after AMI by comparison with other available tools.

METHODS

Fifty-five consecutive patients (mean age, 59 +/- 13 years; 33% women) with first reperfused ST-elevation anterior AMIs and sustained Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow underwent prospectively, < 24 hours after successful primary coronary angioplasty, standard echocardiography and noninvasive CFR assessment in the distal part of the left anterior descending coronary artery, using intravenous adenosine infusion, while in a stable hemodynamic situation. CFR was defined as peak hyperemic left anterior descending coronary artery flow velocity divided by baseline flow velocity. LV ejection fraction (LVEF) was measured using the biplane Simpson's rule. A no-reflow pattern was defined as diastolic deceleration time of basal diastolic coronary flow velocity < 600 ms and/or systolic flow reversal and recovery of LV function as an absolute increase of LVEF >or= 10% at 3-month follow-up. Adverse events were defined as the composite of death, recurrent AMI, and acute heart failure.

RESULTS

In the whole population, the mean LVEF was 46 +/- 5% at baseline and 55 +/- 9% at follow-up. Patients without LV recovery had more severely impaired CFR compared with those with LV recovery (2.1 +/- 0.55 vs 1.46 +/- 0.2, P < .001), as did patients with adverse events compared with those without events (P = .01). Furthermore, CFR was significantly correlated with 3-month LVEF and regional wall motion score (both P values < .01). On multivariate analysis, CFR was an independent predictor of global and regional LV function at follow-up (both P values <or= .01) and of in-hospital cardiac events (P = .02). Receiver-operating characteristic curve analysis demonstrated that a cutoff value of 1.7 for CFR yielded sensitivity of 76% and specificity of 96% to predict LV recovery at follow-up (P < .01).

CONCLUSION

Noninvasive CFR determined < 24 hours after AMI was an independent predictor of LV recovery at 3-month follow-up and of in-hospital adverse cardiac events.