CHICAGO, March 30 Use of a special catheter that sucksout, or aspirates, bits of plaque and blood clot that break loose duringpercutaneous coronary intervention (PCI) significantly enhances blood flowdeep in the heart muscle in patients who are experiencing a heart attack,according to a recently published study. Now, a new analysis of the ThrombusAspiration during Percutaneous Coronary Intervention in Acute MyocardialInfarction (TAPAS) study has shown that the link between deep myocardialperfusion and better clinical outcomes that was apparent at 30 days is stillstrong after one year.
The one-year results of the TAPAS study, which focused on patientssuffering from a type of heart attack known as ST-elevation acute myocardialinfarction (STEMI), are being reported today in a Late-Breaking ClinicalTrials session at the SCAI Annual Scientific Sessions in Partnership withACC i2 Summit (SCAI-ACCi2) in Chicago. SCAI-ACCi2 is a scientific meeting forpracticing cardiovascular interventionalists sponsored by the Society forCardiovascular Angiography and Interventions (SCAI) in partnership with theAmerican College of Cardiology (ACC).
PCI is considered the best treatment for STEMI when it is delivered in atimely fashion by experienced clinicians, because it can rapidly and reliablyopen an artery on the surface of the heart that has been blocked by a bloodclot. However, bits of atherosclerotic plaque and blood clot can break looseduring angioplasty and stenting, traveling downstream to occlude the tinyvessels, or microcirculation, that supply blood deep into the heart muscle.When this happens -- even if the surface artery has been successfully openedduring PCI -- the amount of tissue damaged by the heart attack tends to begreater, recovery of heart function reduced, and the risk of death higher.
In an attempt to improve myocardial perfusion after treatment for heartattack, various catheters have been developed that either aspirate or filterout debris that travels downstream during PCI. The TAPAS study was designed totest the effectiveness of the Export Aspiration Catheter (Medtronic).
Felix Zijlstra, MD, PhD, University Medical Center Groningen, theNetherlands, was the study's senior investigator. For the study, he and hiscolleagues recruited 1,071 patients with STEMI, randomly assigning 535 to PCIsupported by the Export aspiration catheter and 536 to PCI using conventionaltechniques.
To assess the quality of myocardial perfusion, the researchers documentedmyocardial blush grade. A myocardial blush grade of 0 or 1 indicates thatlittle or no x-ray dye has reached from the surface artery into the heartmuscle, a sign that the microcirculation is blocked. A myocardial blush gradeof 3 indicates that x-ray dye has reached deep into the heart muscle, a signof good blood flow through the microcirculation. A myocardial blush grade of 2falls in between. Analysis of the elevated ST-segment on the electrocardiogram-- specifically, its return to a normal baseline -- was also used to gauge thequality of blood flow to the heart muscle.
During angiography, researchers observed a blush grade of 0 or 1 in 17percent of patients treated with the aid of the aspiration catheter and in 26percent of patients treated with conventional PCI (p less than 0.001). At 30days, clinical outcomes were strongly related to the degree of myocardialreperfusion. The rate of death in patients with a myocardial blush grade of0/1, 2 and 3 was 5.2 percent, 2.9 percent and 1.0 percent, respectively(p equals 0.003). The combined rates of repeat heart attack, repeat procedurein the target artery and death in patients with a myocardial blush grade of0/1, 2 and 3 were 14.1 percent, 8.8 percent and 4.2 percent, respectively(p less than 0.001).
At one-year follow-up, mortality was significantly lower in patientstreated with the aspiration catheter (p equals 0.04), as was