Left anterior descending coronary artery flow after primary angioplasty in acute anterior ST-elevation myocardial infarction: How much flow is needed for left ventricular functional recovery?

Abstract

The treatment of choice in acute ST-elevation myocardial infarction (STEMI) is primary percutaneous coronary intervention (PPCI). Although, thrombolysis in myocardial infarction (TIMI) and myocardial blush grade (MBG) measures provide semi-quantitative flow evaluation after PPCI, serial and quantitative volumetric flow evaluation is still lacking. Serial assessment of left anterior descending (LAD) coronary artery flow in patients with anterior myocardial infarction (MI), immediately after PPCI, 48 h later and pre-discharge and compare findings in patients with optimal and suboptimal PPCI result and their relation to left ventricular ejection fraction (LVEF). Velocities in the LAD were recorded within 6 h after PPCI and one week later in 36 patients presenting with acute anterior STEMI. Sixteen patients had TIMI and MBG less than 3 after PPCI were considered to have suboptimal result. Sampling of LAD coronary artery velocity was obtained from trans-thoracic Doppler. Flow in the LAD coronary artery was estimated using heart rates, Doppler time velocity integrals and LAD color Doppler diameters. Diastolic LAD coronary artery flow immediately after PPCI in subjects with suboptimal PPCI, 29 ± 21 ml/min was lower than in those with optimal result, 39.8 ± 21 ml/min, p<0.05. Diastolic flow in the LAD coronary artery increased to 50.3 ± 28.5 ml/min two days after PPCI in patients with suboptimal PPCI, p=0.04, and to 49.6 ± 13.8 ml/min in those optimal result, p=0.04. LVEF increased by 9% in patients with optimal PPCI, p=0.004, and did not change in the other group. (a) After PPCI, flow in the LAD coronary artery was dynamic; (b) in the presence of suboptimal PPCI, early LAD coronary artery flow was reduced; (c) pre-discharge, LAD coronary artery flow increased; and (d) LVEF increased only in optimal PPCI group associated with higher early LAD coronary artery flow.