Serial transthoracic coronary Doppler shows complete reversibility of microvascular obstruction pattern at one month after reperfused acute myocardial infarction.

Abstract

“No reflow” phenomenon is a common complication with significant prognostic repercussions after reperfused acute myocardial infarction. Previous studies have shown the feasibility and prognostic significance of coronary microcirculation assessment by transthoracic Doppler of left anterior descending artery (LAD). The aim of the study was to evaluate the time course of the coronary microcirculation status after acute anterior myocardial infarction reperfused by primary angioplasty with stent on LAD. Material and methods: Twenty-three patients underwent transthoracic echocardiography at 3 days (M0) and one month (M1) after reperfusion, with LAD flow analysis (peak systolic and diastolic velocities, diastolic deceleration time and systolic flow reversal). The patients were divided into two groups, of good reperfusion and “no reflow”, by a 600 ms cut-off of the M0 diastolic deceleration time, previously shown to best discriminate between the two microvascular reperfusion states. Results: Of all patients, 21 survived to M1 and were included in analysis. Microvascular obstruction, as defined, was present in 50% of patients at M0 and it was associated with significantly worse ejection fraction both at M0 and M1 (p=0.01 and 0.04, respectively). Killip class at admission was the only independent predictor of “no reflow”. DDT increased from 661.9±339.3 at M0 to 948.2±201.8 at M1 (p=0.0003). In patients with initial “no reflow”, DDT increased to normal values at M1 (876.2±167.7 vs. 346.3±133.9 at M0, p<0.0001). In these patients, the PDV/PSV ratio decreased at one month (1.91±0.37 vs. 2.70±1.22, p=0.06), by decrease of PDV (0.29±0.06 vs. 0.40±0.19, p=0.03). Conclusions: The parameters of coronary microcirculatory impedance improve significantly at one month after infarction, suggesting delayed full reversibility of the microvascular obstruction.