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APPOSITION II: Self-expanding stent reduces malapposition by factor of 10
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Coverage from the Transcatheter Cardiovascular Therapeutics (TCT) 2010 meeting
Researchers for the APPOSITION II study reported a 10-fold reduction in stent strut malapposition at 3 days with a self-expanding nitinol stent vs. a balloon-expanding stent.
The APPOSITION II study, a prospective, randomized, multicenter trial, compared a self-expanding nitinol stent (Stentys) with a conventional balloon-expanding stent (Vision, Abbott Vascular; Driver, Medtronic) in patients with acute MI. The primary endpoint was stent strut apposition at 3 days as assessed by optical coherence tomography.
A total of 80 patients were randomly assigned to the self-expanding stent (n=43) or the balloon-expanding stent (n=37) between December 2009 and June 2010. Optical coherence tomography and quantitative coronary angiography were completed at 3 days, and clinical follow-up at 30 days and 6 months. Malapposition was defined as the distance between the leading edge of the strut and the leading edge of the contour bigger than the strut thickness.
On optical coherence tomography, fewer struts were malapposed at 3 days in patients who received the self-expanding stent, according to the study results.
A total of 28% of patients treated with balloon-expanding stents showed significant malapposition (defined as ≥5% malapposed struts) at 3 days following the acute MI. None of the patients treated with the self-expanding stent, however, had malapposition (P<.001). Coronary angiography at 3 days showed an in-stent lumen loss of –0.11 ± 0.29 mm3 in the self-expanding stent group vs. 0.04 ± 0.21 mm3 in the control group (P=.01). The negative lumen loss was “expected” with the self- expanding stent technology, and shows that the stent is “indeed increasing in 3 days in size,” according to presenter Robert Jan van Guens, MD, of Erasmus Medical Center, Rotterdam, the Netherlands.
Clinical follow-up at 30 days showed no major adverse cardiac events (including cardiac death, MI, CABG and target lesion revascularization, or stent thrombosis) in either group.