Sirolimus-Eluting Stent Implanted in Human Coronary Artery for 16 Months
A 71-year-old woman, enrolled in the RAndomized study with the sirolimus (SRL)–eluting Bx VELocity balloon-expandable stent (RAVEL) Trial (December 5, 2000), received a single SRL-eluting Bx Velocity stent (Cordis) to treat an 80% proximal left anterior descending (LAD) coronary artery stenosis (Figure 1A). Intravascular ultrasound and angiography at 6 months showed 0% stenosis with no in-stent neointimal proliferation (Figure 1, B and D). The patient remained asymptomatic until presenting with unstable angina on May 3, 2002. Angiography demonstrated subtotal occlusion of the left obtuse marginal. The LAD SRL-eluting stent (deployed 16 months previously) showed 0% stenosis (Figure 1C). The left obtuse marginal lesion was successfully stented, but the patient suffered a fatal stroke 24 hours after coronary intervention.
At autopsy, the LAD SRL-eluting stent was widely patent, and there was a minute thrombus at the ostium of a small side branch (Figure 2A). The stent surface was otherwise well healed. Light microscopy showed mild neointimal thickening (smooth muscle cells within a proteoglycan-rich matrix; Figure 2, B through D). Fibrin was occasionally identified near stent struts, especially within the necrotic core, and was minimal within the neointima (Figure 2, E and F). Inflammatory cells were rare. Scanning electron microscopy showed >80% endothelialization of the stent (Figure 2G). There were small foci of poorly formed endothelial cell junctions and rare platelet aggregates close to the side branch ostium associated with pavement-shaped endothelial cells (Figure 2, H and I).
This SRL-eluting stent was widely patent at 16 months with >80% endothelial coverage. Neointimal healing was nearly complete, with only rare fibrin deposits.
Dr Guagliumi has a consultant agreement with Cordis, the manufacturer of the stents that are the subject of this article.
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The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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