Predilation, sizing and post-dilation scoring in patients undergoing everolimus-eluting bioresorbable scaffold implantation for prediction of cardiac adverse events: development and internal validation of the PSP score

Aims: The aim of the study was to develop a scoring model to evaluate the quality of bioresorbable vascular scaffold (BVS) implantation and determine the model's usefulness in predicting adverse cardiac events. Methods and results: The implantation technique and clinical outcomes of 1,736 lesions treated with BVS were analysed using the GHOST-EU registry. Predilation, scaffold sizing, and post-dilation (PSP) were scored according to the hazard model derived from the weight of these variables. The primary end-point was a one-year device-oriented composite endpoint (DoCE) composed of cardiac death, target vessel myocardial infarction, and clinically driven target lesion revascularisation. Definite/probable scaffold thrombosis was also evaluated as defined by the Academic Research Consortium. The PSP model performance was evaluated by internal validation. Predilation, correct scaffold sizing, and post-dilation with a non-compliant balloon were performed in 95.7%, 50.2%, and 26.2% of the cases and scored 0.63, 1.96 and 1.93 points, respectively, in the PSP-1 model. PSP-1 was an independent predictor of one-year DoCE (HR 0.75, 95% CI: 0.61-0.93; p=0.007), but with poor calibration and discrimination (AUC 0.611, 95% CI: 0.545-0.677). No patient with a maximum PSP-1 score had scaffold thrombosis, compared to those with a non-maximum PSP-1 score (0% vs. 2.3%; p=0.095). Conclusions: At one-year follow-up, the PSP-1 score was an independent predictor of DoCE. External validation and prospective studies are needed to determine the clinical usefulness of this score.