Procedural Predictors for Bioresorbable Vascular Scaffold Thrombosis: Analysis of the Individual Components of the "PSP" Technique.

The technique used at the time of implantation has a central role in determining the risk of thrombosis in bioresorbable vascular scaffolds (BRS). Different definitions of the "optimal" implantation technique exist, however. The impact of individual procedural characteristics on the risk of scaffold thrombosis (ScT) was evaluated in a single-center observational study that enrolled 657 patients (79% males, mean age 63 ± 12 years) with 763 lesions who received a total of 925 BRS for de novo lesions. During a median 1076 (762⁻1206) days' follow-up there were 28 cases of thrombosis. Independent predictors of ScT included the use of predilatation balloons bigger than the nominal BRS diameter (hazard ratio (HR) = 0.4 (0.16⁻0.98), p = 0.04), sizing (implantation in vessels with reference vessel diameter >3.5 mm or <2.5 mm: HR = 5.71 (2.32⁻14.05), p = 0.0002) and the degree of vessel expansion (ratio of minimum lumen to reference vessel diameter, HR: 0.005 (0.0001⁻0.23), p = 0.007). In addition, a mild BRS oversizing (final BRS diameter to vessel diameter 1.14⁻1.28) was associated with a lower thrombosis risk, whereas undersizing and more severe oversizing (final BRS diameter to vessel diameter <1.04 and >1.35, respectively) were associated with an increased risk of ScT (HR = 0.13 (0.02⁻0.59), p = 0.0007). In conclusion, different components of the "optimal" technique have different impacts on the risk of BRS thrombosis. Besides predilatation with a balloon larger than the BRS diameter, correct vessel size selection and a mild to moderate oversizing appear to be protective.