The duration of balloon inflation affects the luminal diameter of coronary segments after bioresorbable vascular scaffolds deployment

Abstract

BackgroundAdequate expansion is critical to achieve optimal Bioresorbable Vascular Scaffolds (BVS) apposition to the vessel wall. However, compared to metallic stents, BVS present different mechanical properties. Hence, slow deployment and maintenance of balloon inflation for at least 30” is recommended for BVS implantation. However, since no evidences are available demonstrating the superiority of a longer balloon dilatation time, the implantation technique is highly variable among different centers.MethodsA total of 24 BVS-treated lesions were included in the present analysis. After BVS deployment at 12 atmosphere (ATM) the balloon was rapidly deflated and scaffold expansion was documented with an angiogram. The same balloon was then inflated again and kept at 12 ATM for 30”. Finally, a further angiogram was obtained to evaluate BVS expansion. Quantitative coronary angiography (QCA) was performed at each step.ResultsA significant increase of minimal luminal diameter (MLD)-to-reference scaffold diameter (RSD) ratio (MLD to RSD Ration, MR-Ratio) from 0.70 ± 0.10 after initial stent deployment to 0.79 ± 0.10 after the 30”-long balloon dilation was observed (p < 0.001). Of note, this result was consistent across all sub-segments, as well as across almost all lesion subgroups. A substantial reduction in the prevalence of residual stenosis from 29 % to 17 % was registered after the 30”-long dilation.ConclusionsOur results strongly support the maintenance of balloon inflation for at least 30” during BVS deployment to achieve optimal scaffold expansion and minimize the occurrence of residual stenosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12872-015-0163-5) contains supplementary material, which is available to authorized users.

Bioresorbable Vascular Scaffold Korean Expert Panel Report

“… 52) Target pressure should be maintained for at least 30 seconds, because a significant larger lumen diameter is obtained with a longer inflation time. 53) …”

A novel stent inflation protocol improves long‐term outcomes compared with rapid inflation/deflation deployment method

“…Thus, the persistent application of a constant inflation pressure until pressure stabilization develops may be a safe and effective approach to fully expand these devices. As with metallic stents, a recent study has shown improved stent expansion with a 30 s duration inflation compared to a rapid inflation/deflation sequence . POP may be attractive with this stent type since lesion and stent characteristics would guide the duration of inflation rather than an arbitrary time.…”

Bioresorbable Vascular Scaffolds—Dead End or Still a Rough Diamond?

“…The PSP technique is distinctively beneficial in the case of aggravated risk of thrombosis, e.g., in diabetic patients [124,138]. In line with this concept, the use of a longer inflation time, as suggested by the producer, allows better for device expansion and a more homogeneous apposition [53]. In order to select the proper size of BVS, the measurement of the target's diameter was observed to be equally accurate under the guidance of either angiography or OCT [139].…”

“…In order to obtain the appropriate mechanical framework of these stents, it became necessary to increase the thickness of the strut, because of lower tensile strength, reduced stiffness and the chance of deformation [35,52]. Studies have shown that in order to avoid strut rupture or abnormal decomposition, ABSORB stents require accurate lesion, judicious patient selection and an appropriate implantation technique, as they are able to stretch up to 0.7 mm beyond the nominal diameter [36,53]. ABSORB stents are radiolucent and therefore may not be visualized in fluoroscopy.…”

“…However, prolonged ischemia appears not to impact BVS efficacy, and their use may be warranted even in chronic total coronary occlusions [97]. Furthermore, as shown by randomized studies, after the implantation of bioresorbable stents, a lower minimal diameter of the vessel lumen significantly increased initial stenosis which results in a greater risk of recoil in vivo [53,81,89]. The mentioned phenomena were caused by an increased strut thickness, greater than in DES; bulky, discontinuous, malapposed struts; structural disruption; and finally, incomplete resorption (even in 3 year observation time (the PRAGUE-19 trial)) [73,86].…”