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Microporus Surface

Microporus Surface

Synopsis

The objective of this study was to examine the relationship between stent surface topography and outcome in patients undergoing implantation of stents with rough and smooth surfaces. Surface topography is considered an important determinant of the bare stent performance. Specifically designed rough surface may increase the drug storing capacity of stents but its direct impact on the risk of thrombosis and restenosis is not known. A total of 200 patients with significant stenosis in native coronary vessels were randomly assigned in a double-blind way to receive either a rough or a smooth-surface stent.

The primary endpoint of the study was late lumen loss. Secondary endpoints included angiographic restenosis and clinical outcomes. The study was designed to test the equivalence of rough-surface stents to smooth-surface stents with respect to late lumen loss based on a non inferiority margin of 0.20 mm. Follow-up angiography was performed in 77% of the patients. Late lumen loss was 1.06 ±0.7 mm in the rough-surface stent group and 1.26 ±0.7 mm in the smooth stent surface group with a mean difference of 20.20 mm (95% CI ±5, 20.43 to ±0.02) between the two stents (P < 0.001 from test for equivalence and P 5 0.08 from test for superiority).

Angiographic restenosis rates were 25% with rough-surface stents and 35% with smoothsurfacestents (P ±5 0.19). These results show that a rough stent surface does not increase late lumen loss after stent implantation as compared with a conventional smooth stent surface.

Surface topography is considered to have an important influence on stent performance. While earlier experimental studies have suggested that stents with a smooth surface reduce thrombogenicity and neointimal proliferation, more recent data show that specially treated rough surfaces may accelerate stent endothelialization,a process that has been associated with less clot formation and neointimal growth after stent implantation. In a double-blind randomized trial, we compared for the first time a stent with rough surface with a stent with smooth surface. We found that the two studied stents were equivalent with respect to the late lumen loss. However, it should be noted that the observed difference favored the rough-surface stent. There was also a trend toward a reduced rate of angiographic  restenosis with this stent. Both types of stents were associated with similar rates of thrombosis-related events. These data are important as a specially elaborated rough surface may increase the drug storage capacity of the stent. This is the first clinical study specifically designed to evaluate the influence of stent surface topography on the outcomes of patients undergoing coronary stenting. Previous data on the relationship between surface topography and stent performance have been provided from experimental studies carried out in in vitro or animal models. Thus, de Scheerder et al. [16] found that stents with a smoothed surface by electrochemical polishing caused less clot formation compared to nonpolished stents after implantation in a rat carotid arteriovenous shunt model. In the same study, when the two stent types were implanted in the right coronary arteries of healthy pigs, mural thrombi at 7 days were less frequently found among smooth-surface stents. In addition, at 6 weeks after implantation, neointimal hyperplasia decreased by 40% in smooth-surface stents compared to stents with a rougher surface [16]. More recently, in an in vitro model with fresh human whole blood, Tepe et al. [17] evaluated the thrombogenicity of different peripheral stent types. They reported that smoothing the stent surface clearly reduced their thrombogenicity [17]. Based on these data and some other experimental study, it has been suggested that a smooth surface can help prevent the activation and aggregation of platelets that lead to thrombus formation, reduce the local concentration of macrophages,and decrease neointimal hyperplasia of coronary stents [25–27]. These have constituted the rationale for recommending the use of stents with smooth surface to improve patients’ outcomes.Recent work, however, suggests that a rough surface may be associated with a more favorable timing of stent endothelialization. Thus, in an in vitro model ,investigators found that creating surfaces with parallel microgrooves accelerated the migration rate of endothelial cells compared to smooth controls, suggesting a potential effect of grooved endovascular stent surfaces on faster endothelialization times.

 


 

Rough Surface vs. Smooth Surface - Dr.Kastrati


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