The randomized physiologic assessment of thrombus aspiration in patients with acute myocardial infarction with ST-segment elevation (PATA STEMI) trial: Final results

Background: Routine manual thrombus aspiration is superior to standard primary PCI (pPCI) 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 assessed by an index of microcirculatory resistance (IMR) in a randomised fashion. Methods: We performed a randomized, controlled clinical trial to evaluate impact of thrombus aspiration on microcirculatory resistance after pPCI in 128 patients with the first STEMI randomly assigned to thrombus aspiration or standard pPCI group before coronary angiography. The primary endpoint was defined as a mean value of corrected IMR (IMRcorr) in thrombus aspiration compared to conventional PCI group. Myocardial perfusion grade, resolution of ST‐segment elevation, infarct size, left ventricle remodeling and rate of adverse cardiac events were secondary endpoints. Results: Manual thrombus aspiration, as compared with standard pPCI, resulted in significantly lower IMRcorr (27,5+/‐16,8 U vs. 39,9+/‐32,7 U, P=0,039). Treatment with thrombus aspiration, as compared with conventional PCI, resulted in similar rates of myocardial perfusion grade 0 or 1 (21,5% vs. 28,6%; RR 0,75; 95% CI, 0,41 to 1,38; P=0,36) and complete resolution of ST‐segment elevation (61,5% vs. 49,2%; RR 1,25; 95% CI, 0,91 to 1,71, P=0,16), with lower infarct size (AUC CK 26157,6+/‐40090,0U vs. 32013,6+/‐52676,1U, P=0,026) and similar median value of WMSI (1,23 vs 1,23), LV sphericity volume index (0,43 vs. 0,41) and similar rate of LV remodeling (27,9 vs 18,5%, p=0,21). The rate of adverse events (death, myocardial infarction, stroke or hospitalization for heart failure) was similar 4,6% vs, 11,1%, P=0,20. In a multiple regression model with the log‐transformed IMR as dependent variable, after adjusting for clinical, angiographic and procedural variables, thrombus aspiration was not an independent predictor of lower IMR (28.4 U; 95% CI, 24.7 to 32.8 U, vs. 32.4 U; 95% CI, 28.1 to 37.4 U; estimate 0,877, 95% CI 0,715‐1,077, P=0.21). Conclusions: Manual thrombus aspiration reduces microcirculatory resistance indicating better myocardial perfusion compared to conventional PCI in patients with STEMI. However, routine manual thrombus aspiration is not an independent predictor of reduced microcirculatory resistance. Reduction in microcirculatory resistance of 12,3% achieved by thrombus aspiration is not sufficient to allow echocardiografic improvement in STEMI patients at mid‐term follow up.