Relationship Between TIMI Frame Count and Clinical Outcomes After Thrombolytic Administration

Abstract

Background —The corrected TIMI frame count (CTFC) is the number of cine frames required for dye to first reach standardized distal coronary landmarks, and it is an objective and quantitative index of coronary blood flow. Methods and Results —The CTFC was measured in 1248 patients in the TIMI 4, 10A, and 10B trials, and its relationship to clinical outcomes was examined. Patients who died in the hospital had a higher CTFC (ie, slower flow) than survivors (69.6±35.4 [n=53] versus 49.5±32.3 [n=1195]; P =0.0003). Likewise, patients who died by 30 to 42 days had higher CTFCs than survivors (66.2±36.4 [n=57] versus 49.9±32.1 [n=1059]; P =0.006). In a multivariate model that excluded TIMI flow grades, the 90-minute CTFC was an independent predictor of in-hospital mortality (OR=1.21 per 10-frame rise [95% CI, 1.1 to 1.3], an ≈0.7% increase in absolute mortality for every 10-frame rise; P <0.001) even when other significant correlates of mortality (age, heart rate, anterior myocardial infarction, and female sex) were adjusted for in the model. The CTFC identified a subgroup of patients with TIMI grade 3 flow who were at a particularly low risk of adverse outcomes. The risk of in-hospital mortality increased in a stepwise fashion from 0.0% (n=41) in patients with a 90-minute CTFC that was faster than the 95% CI for normal flow (0 to 13 frames, hyperemia, TIMI grade 4 flow), to 2.7% (n=18 of 658 patients) in patients with a CTFC of 14 to 40 (a CTFC of 40 has previously been identified as the cutpoint for distinguishing TIMI grade 3 flow), to 6.4% (35/549) in patients with a CTFC >40 ( P =0.003). Although the risk of death, recurrent myocardial infarction, shock, congestive heart failure, or left ventricular ejection fraction ≤40% was 13.0% among patients with TIMI grade 3 flow (CTFC ≤40), the CTFC tended to segregate patients into lower-risk (CTFC ≤20, risk of adverse outcome of 7.9%) and higher-risk subgroups (CTFC >20 to ≤40, risk of adverse outcome of 15.5%; P =0.17). Conclusions —Faster (lower) 90-minute CTFCs are related to improved in-hospital and 1-month clinical outcomes after thrombolytic administration in both univariate and multivariate models. Even among those patients classified as having normal flow (TIMI grade 3 flow, CTFC ≤40), there may be lower- and higher-risk subgroups.