First-generation drug eluting stents (DES) reduced the incidence of restenosis and need for repeated target lesion revascularization but, in autoptic studies, frequently resulted in incomplete endothelial coverage, which is an important predictor of late adverse events and increased mortality after stent implantation. More recently, not only uncovered, but also malapposed or protruding struts have been considered vulnerable structures, as they are deemed to perturb blood flow, whereas only struts well embedded into the vessel wall are considered stable. We compared the number of uncovered and of other vulnerable (protruding or malapposed) struts among three different second-generation drug-eluting stents (DES) (Cre8, Biomatrix, Xience), using optical coherence tomography (OCT) 6 months after implantation. Moreover, we analyzed the relationship between the percentage of vulnerable struts and the clinical characteristics of patients. 60 patients with stable angina or non-ST-Elevation acute coronary syndrome and indication to percutaneous angioplasty were randomly assigned to receive one of the three DES. After 6 months, OCT images were obtained. After 6 months, OCT images were obtained (1289 cross sections; 10,728 struts). None of the three DES showed non-coated struts or areas of stent thrombosis. Significant differences in the average number of protruding struts (Cre8: 33.9 ± 12.6; Biomatrix: 26.2 ± 18.1; Xience: 13.2 ± 8.5; p < 0.001) and in the proportion of malapposed struts (Cre8: 0.7%; Biomatrix: 0.9%; Xience: 0.0%; p = 0.040) and of incomplete stent apposition area (Cre8: 10.4%; Biomatrix: 4.7%; Xience: 0.7%; p < 0.001) were observed. No significant difference was found in neointimal hyperplasia area with a not significant tendency toward greater minimal and maximal struts thickness for Biomatrix. In comparison with Cre8 and Biomatrix, Xience showed a significantly lower proportion of vulnerable struts in all clinical sub-groups considered. In the group of 60 patients a significant relation was found between age and number of vulnerable struts (p = 0.014). The three second-generation DES were similarly effective in permitting neo-intimal formation and complete struts coating 6 months after implantation, but Cre8 and Biomatrix showed a greater proportion of protruding and malapposed struts.

Trail Registry: Clinical Trials.gov Identifier: NCT02850497.