ABSTRACT
BACKGROUND: Coronary microvascular resistance is increased after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI), which may be related in part to changed left ventricular (LV) dynamics. Therefore we studied the coronary microcirculation in relation to systolic and diastolic LV function after STEMI. METHODS: The study cohort consisted of 12 consecutive patients, all treated with primary PCI for a first anterior wall STEMI. At 4 months, we assessed pressure-volume loops. Subsequently, we measured intracoronary pressure and flow velocity and calculated coronary microvascular resistance. Infarct size and LV mass were assessed using magnetic resonance imaging. RESULTS: Patients with an impaired systolic LV function due to a larger myocardial infarction showed a higher baseline average peak flow velocity (APV) than the other patients (26 ± 7 versus 17 ± 5 cm/s, p = 0.003, respectively), and showed an impaired variable microvascular resistance index (2.1 ± 1.0 versus 4.1 ± 1.3 mmHg cm(-1)âs(-1), p = 0.003, respectively). Impaired diastolic relaxation time was inversely correlated with hyperaemic APV (r = -0.56, p = 0.003) and positively correlated with hyperaemic microvascular resistance (r = 0.48, p = 0.01). LV dilatation was associated with a reduced variable microvascular resistance index (r = 0.78, p = 0.006). CONCLUSION: A larger anterior myocardial infarction results in impaired LV performance associated with reduced coronary microvascular resistance variability, in particular due to higher coronary blood flow at baseline in these compromised left ventricles.
ABSTRACT
BACKGROUND: Patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) with the Proxis system (St. Jude Medical, St. Paul, MN, USA) achieved significantly better microvascular flow as measured by ST-segment resolution. However, no differences were observed in left ventricular ejection fraction or infarct size as obtained by cardiovascular magnetic resonance imaging. The goal of the present study was to evaluate the effect of combined proximal embolic protection and thrombus aspiration on core-lab adjudicated angiographic outcomes. METHODS: In the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-Elevation (PREPARE) study, patients were randomised to primary PCI with the Proxis system (n=141) or primary PCI alone (n=143). An independent core laboratory re-evaluated all angiograms and adjudicated the angiographic outcomes and computerised quantitative blush evaluation (QuBE) value. RESULTS: There were no significant differences in Thrombolysis In Myocardial Infarction (TIMI) flow grade, myocardial blush grade, or angiographic signs of distal embolisation among the two arms. QuBE values did not significantly differ between the Proxis-treated patients and control patients (15.1±5.4 vs. 15.8±5.5, respectively, p=0.34). CONCLUSION: Primary PCI with combined proximal embolic protection and thrombus aspiration in STEMI patients more frequently resulted in complete immediate ST resolution compared with control patients. However, there were no significant differences in core laboratory adjudicated angiographic outcomes. (Neth Heart J 2010;18:531-6.).
ABSTRACT
OBJECTIVES: The aim of the study was to evaluate whether primary percutaneous coronary intervention (PCI) with combined proximal embolic protection and thrombus aspiration results in smaller final infarct size and improved left ventricular function assessed by cardiovascular magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients compared with primary PCI alone. Background Primary PCI with the Proxis system improves immediate microvascular flow post-procedure as measured by ST-segment resolution, which could result in better outcomes. METHODS: The ancillary CMR study included 206 STEMI patients who were enrolled in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-Elevation (PREPARE) trial. CMR imaging was assessed between 4 and 6 months after the index procedure. RESULTS: There were no significant differences in final infarct size (6.1 g/m(2) vs 6.3 g/m(2), p = 0.78) and left ventricular ejection fraction (50% vs 50%, p = 0.46) between both groups. Also, systolic wall thickening in the infarct area (44% vs 45%, p = 0.93) or the extent of transmural segments (8.3% of segments vs 8.3% of segments, p = 0.60) showed no significant differences. The incidence of major adverse cardiac and cerebral events at 6 months was similar in the Proxis and control group (8% vs 10%, respectively, p = 0.43). Conclusions Primary PCI with combined proximal embolic protection and thrombus aspiration in STEMI patients did not result in significant differences in final infarct size or left ventricular function at follow-up CMR. In addition, there was no difference in the incidence of major adverse cardiac and cerebral events at 6 months. TRIAL REGISTRATION: number ISRCTN71104460.
