Pressure rinsing of coronary stents immediately before implantation reduces inflammation and neointimal hyperplasia
Antoni Bayes-Genis, MDa,
Allan R. Camruda,
Michael Jorgensona,
Janis Donovana,
Kristin L. Shogrena,
David R. Holmes, Jr, MD, FACCa and
Robert S. Schwartz, MD, FACCa
a Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, Minnesota, USA
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Figure 1 Stent-cleaning chamber. The stent-cleaning chamber used in this study was made with silicone rubber tubing connected between two hemostatic valves (see Methods for details).
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Figure 2 Ultrastructural examination of the stent surface. Pre-mounted balloon-expandable 16-mm NIR stents were expanded ex-vivo under sterile conditions as untouched, handled, and rinsed and evaluated by scanning electron microscope. Variable amounts of surface contaminants were visualized in untouched stents (A, B, C), and abundant and diffuse surface foreign materials (likely powder from the gloves) were seen in handled stents (D, E, F). After rinsing with high pressure most contaminants were eliminated from the stent surface, which had a smoother appearance (G, H, I).
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Figure 3 Representative linear fit curves for injury-dependent neointimal thickness in the four studied groups. (A) shows regression lines for handled + not-rinsed and handled + rinsed stents, which showed significantly different slopes (allowing any intercept: p = 0.004; forcing a fixed intercept: p = 0.003). (B) injury-dependent neointimal thickness regression lines for untouched + not-rinsed and untouched + rinsed stents, which also showed statistically significant differences in slopes (allowing any intercept: p = 0.037; forcing a fixed intercept: p = 0.011). Measurements were made on three cross-sections from each stent.
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Figure 4 Histologic example of handled + not-rinsed and handled + rinsed stents. The two arteries have a similar mean injury score but a different neointimal response. (A) The thicker neointima in the handled + not-rinsed stent artery overlies the struts that elicited more inflammation (in asterisks). (B) handled + rinsed struts elicited minimal neointima even with severe medial damage (arrows). Modified von Gieson stain for plastic embedded arteries.
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Figure 5 (A) Representative linear fit curves of injury-dependent inflammation in the four studied groups. Rinsed stents (untouched + rinsed = c; handled + rinsed = d) induced less inflammation than not-rinsed stents (handled + not-rinsed = a; untouched + not-rinsed = b). Significant differences in intercepts were found both between handled + not-rinsed and handled + rinsed stents (p = 0.008) and between untouched + not-rinsed and untouched + rinsed stents (p = 0.018). B, C, and D are hematoxylin-eosin microphotographs of peri-strut inflammation. (B) mild inflammatory response around untouched + not-rinsed stent struts; (C) moderate inflammation around handled + not-rinsed stent struts with resulting thicker neointima. Note the presence of an inflammatory reaction in the adventitia; (D) absent inflammation around a handled + rinsed strut. Bar = 0.2 mm.
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