Proxis embolic protection system could be efficacious in the PCI setting

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WASHINGTON—The Proxis embolic protection system is feasible and safe in the setting of STEMI, and effectively retrieves embolic debris in most patients, according to the late breaking clinical PREPARE trial presented Wednesday at the 20th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium.

Karel T. Koch, MD, from the Academic Medical Center at the University of Amsterdam in the Netherlands, presented the prospective randomized PREPARE [PRoximal Embolic Protection in Acute MI and Resolution of ST-Elevation] trial, which assessed proximal microcirculatory protection in patients with acute MI undergoing primary PCI.

Koch said that the investigator-initiated, randomized trial comparison of primary PCI with Proxis system versus primary PCI alone with blinded evaluation of end points. Two centers participated, and 140 patients were designated to each arm.

The researchers used St. Jude Medical’s Proxis system, which has a full-length flexible catheter, sealing balloon at the tip and a CO2 based inflation device. Koch explained that the system is deployed proximal to target lesion before crossing and inflation of balloon suspends antegrade flow during lesion intervention.

Koch said the primary endpoint was ST-segment elevation resolution (STR) over time.

The immediate results (indicated by the last contrast injection) of STR completion (greater than 70 percent) was 66 percent in the Proxis arm and 50 percent in the control arm, which is highly statistically significant. At 120 minutes from procedure, the Proxis arm had 78 percent STR completion, and the control arm had 76 percent.

Based on their findings, Koch concluded that because complete STR was better in Proxis-treated patients compared to control patients, primary PCI with combined proximal embolic protection and aspiration leads to better immediate microvascular flow in STEMI patients.

He noted that due to the small number of patients, the study was underpowered to assess the secondary endpoint of composite of death, MI, target vessel revascularization and stroke at 30 days.

The time of implementing the device adds three minutes to the procedure, which is statistically significant, but Koch noted that it only increased the median time from 14 to 17 minutes.

Koch speculated that the device could be safely implanted in 94 percent of patients.