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GRONINGEN, The Netherlands, June 6 -- Aspirating the thrombus during percutaneous coronary intervention saves lives and improves clinical outcomes after heart attack, researchers found.

Compared with standard PCI, manual thrombus removal before stenting cut the combined rate of one-year cardiac death and non-fatal reinfarction (5.6% versus 9.9%, P=0.009) while reducing overall mortality (P=0.042), reported Pieter-Jan Vlaar, M.Sc., of University Medical Centre Groningen, and colleagues in the June 7 issue of The Lancet.

These one-year findings from the Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS) confirm those reported earlier this year at the American College of Cardiology.

As at that meeting, the researchers again cautioned that the study was underpowered to show differences in mortality and other clinical outcomes. (See ACC: Manual Clot Removal Boosts Clinical Benefit of PCI in Acute MI).

Nevertheless, the trial is "the first convincing victory against incomplete myocardial perfusion," according to Francesco Burzotta, M.D., Ph.D., and Filippo Crea, M.D., of the Catholic University of the Sacred Heart in Rome, writing in an accompanying editorial.

"The notion that, during primary PCI, aspiration is better than predilation will probably soon affect clinical guidelines," they wrote. "This development will be favored by the low cost and easy use of thrombus-aspirating catheters, which make them ready for use in all catheterization laboratories that treat patients with acute myocardial infarction."

Primary outcomes from the trial showed thrombus aspiration increased myocardial blush grades, reflecting better reperfusion, and better resolution of ST-segment elevation (both P<0.001), as reported in an earlier analysis in the Feb. 7 issue of the New England Journal of Medicine. (See: Manual Thrombus Removal Improves Stent Outcome).

The prospective single-center trial included 1,060 patients with ST-segment elevation MI who were randomized to percutanteous coronary intervention alone or with thrombus aspiration using the Export Aspiration Catheter. Patients were followed through at least one year.

All patients got standard treatment with heparin, aspirin, a 600-mg loading dose of clopidogrel (Plavix), and abciximab (ReoPro). Only about half the patients had angiographic evidence of thrombus.

At one-year follow-up, 66 patients had died with 83.3% regarded as cardiac-related deaths because of lack of an unequivocal non-cardiac cause of death.

Among the findings for PCI plus thrombus aspiration compared with conventional PCI at one year, the researchers reported:

• No significant change in major adverse cardiac events overall (16.6% versus 20.3%, hazard ratio 1.26, P=0.10).

• Half as many cases of cardiac death (3.6% versus 6.7%, HR 1.93, P=0.020).

• Reduced rates of cardiac death or nonfatal reinfarction (5.6% versus 9.9%, HR 1.81, P=0.009).

• Lower all-cause mortality rates (4.7% versus 7.6%, HR 1.67, P=0.042).

• Slightly reduced reinfarction rates (2.2% versus 4.3%, HR 1.97, P=0.05).

• Half as many angiographically proven stent thrombosis events (1.1% versus 2.2%, HR 2.05, P=0.15).

Thrombus aspiration was a stronger risk factor for cardiac death or nonfatal reinfarction in the multivariate analysis (odds ratio 0.54, P=0.025) than age (OR 1.04, P=0.001) or heart rate at admission (OR 1.02, P=0.027), although diabetes put patients at greatest risk (OR 3.22, P<0.0001).

The researchers also found that aspirated clots included both those composed primarily of platelets and those composed of fibrin and red blood cells. "Thrombus aspiration is therefore of additional value during primary

PCI, since currently used antiplatelet agents mainly target white platelet clots."

The researchers noted that the study was limited by lack of systematic measurement of infarct size and left ventricular function.

However, "the main limitation, in addition to its single-centre design, is the lack of information on the predictors of the beneficial effects of thrombus aspiration," Drs. Burzotta and Crea said.

Prior studies have suggested the benefit was mainly among patients with large thrombi and total artery occlusion, they said.

The study was funded by Medtronic and the Thorax Centre of the University Medical Centre Groningen. The researchers reported that they had no conflicts of interest. Drs. Burzotta and Crea reported that they had no conflicts of interest.

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