TIMI frame count immediately after primary coronary angioplasty as a predictor of functional recovery in patients with TIMI 3 reperfused acute myocardial infarction

OBJECTIVES The purpose of this study was to evaluate whether higher coronary blood flow, estimated by the corrected Thrombolysis In Myocardial Infarction (TIMI) frame count (CTFC), is related to better functional and clinical outcome after successful percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI). BACKGROUND Experimental studies have found that functional recovery of the infarcted myocardium was associated with increased blood flow (reactive hyperemia) to the infarcted bed shortly after reperfusion. METHODS We measured CTFC immediately after successful (TIMI 3) primary PTCA in 104 consecutive patients with their first AMI. Wall motion score index (WMSI) and the presence of pericardial effusion were assessed by two-dimensional echocardiography before and one month after PTCA. RESULTS The patients were divided into two groups according to mean CTFC for corresponding coronary artery of the control group: TIMI 3 slow group (45 patients, 40 > CTFC ≥ 23) and TIMI 3 fast group (59 patients, CTFC < 23). There were no significant differences in the baseline characteristics and WMSI before reperfusion between the two groups. Improvement of WMSI in the TIMI 3 fast group was significantly greater than that of the TIMI 3 slow group (1.33 ± 0.52 vs. 0.60 ± 0.34, p < 0.001). Pericardial effusion and intractable heart failure were observed more frequently in the TIMI 3 slow group than in the TIMI 3 fast group (27 vs. 10%; p < 0.05, 36 vs. 17%; p < 0.05). Corrected TIMI frame count, assessed as a continuous variable, had a significant correlation with the change in WMSI (r = 0.60, p < 0.001) after adjusting for age, gender, history of hypertension, history of diabetes, elapsed time to PTCA, collateral grade, presence of antegrade flow before PTCA and number of diseased vessels. CONCLUSIONS Lower CTFC of the infarct-related artery immediately after PTCA was associated with greater functional recovery; and hence, CTFC can predict clinical and functional outcome in patients with successful PTCA.