Originally Published MDDI July 2002
|The thrombectomy device is a dual-channeled catheter capable of grabbing and excising a blood clot and removing the resulting pieces.
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Balloon angioplasty followed by stenting has proven to be an effective procedure for treating blood clots in coronary arteries, which can cause a heart attack or unstable angina. Nevertheless, the procedure poses a risk of moving a blood clot, or its fragments, further along the artery, which can result in yet another heart attack, or stroke. Results of one of the first studies of its kind now suggest that use of an experimental pretreatment technique, thrombectomy, can reduce this risk by removing the clot from the body.
During the study, researchers at the General Hospital of Vienna (Vienna, Austria) and the University of Vienna examined use of the X-sizer thrombectomy device developed by Endicor Medical Inc. (San Clemente, CA). The device is essentially a dual-channeled catheter that is threaded through the blood vessels to the area of blockage in a manner resembling angioplasty techniques. When this area is reached, a spinning helical tip in the first channel of the device is used to fragment the blood clot. At the same time, a miniature vacuum system in the second channel removes the clot pieces.
The study included 66 patients who were to be treated for heart attack or unstable angina. The subjects were randomly assigned to receive angioplasty alone or angioplasty plus treatment with the X-sizer device. Certain aspects of blood flow around the heart and in the microvessels were studied, including ST-segment resolution, which is a marker of heart function. ST-segment resolution was observed immediately after treatment in 83% of patients treated with suction plus angioplasty, compared with 52% of those treated with angioplasty alone.
|Thrombus engagement, removal, and aspiration are controlled by the device's hand unit.|
The group observed that ST-segment resolution was significantly better both immediately after treatment and 6 hours later in X-sizer-treated patients, compared with patients who received only angioplasty. According to Gilbert Beran, MD, one of the investigators, thrombectomy treatment with the X-sizer appeared to be particularly effective when used in arteries that were larger than 3 mm in diameter.
Peter Siostrzonek, MD, associate professor of medicine at the General Hospital of Vienna Department of Cardiology and the University of Vienna, explains that the two-step treatment takes only 10 to 20 minutes longer than angioplasty alone. Says Siostrzonek, "It appears that more X-sizer patients regained circulation that was closer to normal. We believe that faster return of blood flow is associated with greater protection of the affected heart muscle and therefore a better clinical outcome since more heart muscle may be saved."
The study results are considered to be preliminary and must still be confirmed through more-extensive trials. Beran notes that, "In Europe, a larger multicenter trial including more than 15 centers is currently running." He says the study will involve participation of more than 200 patients. He adds, "Due to the higher number of patients, the aspect of clinical outcome could be more focused."
Siostrzonek agrees that "larger trials are needed to determine whether the X-sizer treatment will result in a better clinical outcome." The X-sizer system is used clinically in several countries but is still considered experimental in the United States.
Asked if the group intends to examine the potential effect of thrombectomy on restenosis, Beran comments, "That's a very interesting question, and we are about to evaluate these data out of our patient sample that were treated with the X-sizer."
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