TAPAS: Myocardial perfusion results may change the practice of cardiology

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CHICAGO—Use of a special catheter that aspirates bits of plaque and blood clots that break loose during PCI significantly enhances blood flow deep in the heart muscle in patients who are experiencing a heart attack. The link between deep myocardial perfusion and better clinical outcomes that was apparent at 30 days is still strong after one year, according to the TAPAS (Thrombus Aspiration during PCI in Acute MI) trial, presented on Sunday during the SCAI-ACCi2 Late Breaking Clinical Trials at the 2008 American College of Cardiology (ACC) Scientific Sessions.

Felix Zijlstra, MD PhD, of the Thoraxcenter at the University Medical Center Groningen in The Netherlands, and his colleagues undertook the single center, prospective, randomized trial, which focused on patients suffering from STEMI. He unveiled the one-year results.

The trial’s primary endpoint was myocardial blush grade (core lab); and the Secondary endpoints were ST-segment elevation resolution; 30-day death and death/reinfarction; and one-year death and death/reinfarction, Zijlstra said. The TAPAS trial was designed to test the effectiveness of the Export Aspiration Catheter (Medtronic).

For the study, Zijlstra said that he and his colleagues recruited 1,071 patients with STEMI, randomly assigning 535 to PCI supported by the Export aspiration catheter and 536 to PCI using conventional techniques. In both groups, 530 completed a follow-up at one-year, which is 99 percent

The analysis of the elevated ST-segment on the electrocardiogram—specifically, its return to a normal baseline was also used to gauge the quality of blood flow to the heart muscle.

During angiography, researchers observed a blush grade of 0 or 1 in 17 percent of patients treated with the aid of the aspiration catheter and in 26 percent of patients treated with conventional PCI. At 30 days, clinical outcomes were strongly related to the degree of myocardial reperfusion.

The researchers found that the rate of death in patients with a myocardial blush grade of 0/1, 2 and 3 was 5.2 percent, 2.9 percent and 1 percent, respectively. The combined rates of repeat MI, repeat procedure in the target artery and death in patients with a myocardial blush grade of 0/1, 2 and 3 were 14.1 percent, 8.8 percent and 4.2 percent, respectively.

Based on the trial’s findings, Zijlstra said that myocardial blush grade predicts clinical outcome at one year; and thrombus aspiration results in a lower mortality and combined mortality and non-fatal reinfarction at 1 year.
In a response commentary, David Cox, MD, co-director of interventional cardiology at the Methodist Hospitals in Gary Indiana called the trial a “practice-changing paper.”
Prior to TAPAS, Cox said that that “common wisdom was to only use thrombectomy if you saw a large clot.”

“Congratulations again to our European colleagues for: mediam D2B was 27 minutes; randomized before angiography; 92 percent received 2b3a; and 10 percent of patients were excluded,” Cox commented.

Cox said that among the results, it was important that “all the surrogate endpoints were correlated with decreased mortality.”

While Cox conveyed the importance of the TAPAS results, he said that he would like to see a multi-center, randomized trial conducted, in order to investigate whether “we should change the way we practice.”

He concluded that “the findings of TAPAS are fascinating.”