Relation of Phasic Coronary Flow Velocity Characteristics With TIMI Perfusion Grade and Myocardial Recovery After Primary Percutaneous Transluminal Coronary Angioplasty and Rescue Stenting

Abstract

Background —A residual stenosis and/or microvascular damage have been proposed as mechanisms of TIMI 2 flow for acute myocardial infarction. Coronary flow dynamics were assessed in patients with TIMI 2 flow to predict whether additional intervention would improve TIMI grade. Methods and Results —In 35 patients who had a successfully recanalized anterior acute myocardial infarction using angioplasty or rescue stenting, coronary flow patterns were compared with corresponding TIMI grade and regional left ventricular wall motion (LVWM) 1 month after the intervention. After angioplasty, the time-averaged peak velocity (APV) was lower in patients with TIMI 2 flow (n=22) than in those with TIMI 3 flow (n=13; 7.9±3.9 versus 20.6±5.1 cm/s; P <0.001). Two different flow patterns were recorded in patients with TIMI 2 flow (versus TIMI 3, P <0.001); patients with type 1 TIMI 2 flow (n=15) had a reduced diastolic APV (8.3±4.8 versus 24.2±7.4 cm/s), prolonged diastolic deceleration time (1176±455 versus 728±205 ms), and a small diastolic/systolic APV ratio (1.3±0.6 versus 2.1±0.7); patients with type 2 TIMI 2 flow (n=7) had systolic flow reversal (systolic APV, −7.9±4.6 versus 11.7±4.5 cm/s), a rapid diastolic deceleration time (221±84 versus 728±205 ms), and a negative diastolic/systolic APV ratio (−2.1±1.4 versus 2.1±0.7). A significantly lower mean chord LVWM (−3.0±0.2 versus −1.9±0.8; P <0.001) and a greater number of chords <−2SD (50±2 versus 28±18; P <0.001) were present in patients with type 2 versus type 1 TIMI 2 flow. Stenting increased TIMI 2 flow to TIMI 3 flow more in patients with type 1 than type 2 flow (67% versus 0%; P =0.003). Patients with TIMI 2 flow after stenting continued to demonstrate a type 2 pattern, and they had poor LVWM recovery. Conclusions —The differentiation between 2 types of TIMI 2 flow can predict the improvement of TIMI grade and LVWM recovery after additional stenting.