Combined Proximal EPS With Thrombus Aspiration Studied

October 19, 2009—In the Journal of the American College of Cardiology: Cardiovascular Interventions, Joost D. E. Haeck, MD, et al published findings from the PREPARE (Proximal Embolic Protection in Acute Myocardial Infarction and Resolution of ST-Elevation) study (2009;2:934-943). The purpose of this study was to evaluate the effectiveness of combined proximal embolic protection with thrombus aspiration using the Proxis embolic protection system (St. Jude Medical, Inc., St. Paul, MN) in ST-segment elevation myocardial infarction patients. The background of the study is that embolization during primary percutaneous coronary intervention (PCI) may result in microvascular obstruction, reduced myocardial perfusion, and impaired prognosis.

In this study, 284 patients were randomized to primary PCI with the Proxis system versus primary PCI alone after angiography. The primary endpoint was the occurrence of complete (70%) ST-segment resolution (STR) at 60 minutes measured by continuous ST-segment Holter.

The investigators reported that there was no significant difference in the occurrence of the primary endpoint (80% vs 72%; P = .14). However, immediate complete STR (at time of last contrast) occurred in 66% of Proxis-treated patients and 50% in control patients (absolute difference, 16.3%; 95% confidence interval, 4.3%–28.2%; P = .009). A significantly lower ST-segment curve area (0–3 hours after primary PCI) was observed in the Proxis arm (5,192 µV/min vs 6,250 μV/min; P = .037). Major adverse cardiac and cerebral events at 30 days occurred with similar frequency in both groups (6 vs 10).

There was no significant difference in complete STR at 60 minutes in this proof-of-concept study. However, the investigators observed a significant difference in immediate complete STR in Proxis-treated patients, better STR at later time points, and a reduction of electrocardiogram injury current over time compared with control patients. The results suggest that primary PCI with the Proxis system may lead to better immediate microvascular flow in ST-segment elevation myocardial infarction patients.