The randomized physiologic assessment of thrombus aspirtion in patients with ST-segment Elevation acute Myocardial Infarction trial (PATA STEMI)

Abstract

Background: Routine thrombus aspiration is superior to conventional primary Percutaneous Coronary Intervention (PCI) in terms of improved myocardial perfusion in patients with acute myocardial infarction with ST-segment Elevation (STEMI). However, myocardial perfusion after thrombus aspiration has not been evaluated by a quantitative Index of Microcirculatory Resistance (IMR). Methods: We performed a randomized, controlled clinical trial to evaluate impact of manual thrombus aspiration (the Eliminate aspiration catheter, Terumo Medical Supply, Japan) on microcirculatory resistance after primary PCI in 128 patients with the first STEMI randomly assigned to thrombus aspiration or conventional primary PCI group before coronary angiography. The primary endpoint was defined as a significant reduction of IMR in thrombus aspiration compared to conventional PCI group. Myocardial perfusion grade and resolution of ST-segment elevation were also assessed. Infarct size and left ventricle remodeling were assessed by echocardiographic indices. Results: Manual thrombus aspiration, as compared with conventional PCI, resulted in significantly lower IMR (31.9±21.3 U vs. 47.0±35.8 U, P = 0.0082). Treatment with thrombus aspiration, as compared with conventional PCI, resulted in similar rates of myocardial perfusion grade 0 or 1 (20.8% vs. 29.4%; relative risk, 0.71; 95% CI, 0.38 to 1.30; P=0.26) and complete resolution of ST-segment elevation (59.7% vs. 47.1%; relative risk, 1.27; 95% CI, 0.90 to 1.79, P=0.17). In a multiple regression model with the log-transformed IMR as dependent variable, after adjusting for clinical, angiographic and procedural variables, thrombus aspiration remained a strong independent predictor of lower IMR (27.14 U; 95% CI, 23.79 to 30.95 U, vs. 36.11 U; 95% CI, 30.74 to 42.41 U, P=0.0076). Histopathological examination confirmed successful thrombus aspiration in 89.6% of patients. The results of echocardiographic analysis will be available at the time of the presentation. Conclusions: Manual thrombus aspiration reduces microcirculatory resistance indicating better myocardial perfusion compared to conventional PCI in patients with STEMI.