Comparison of acute gain and late lumen loss after PCI with bioresorbable vascular scaffolds versus everolimus-eluting stents: an exploratory observational study prior to a randomised trial.

AIMS: The study sought to compare the acute gain and two-year follow-up late lumen loss (LLL) between the Absorb bioresorbable vascular scaffold (BVS) and the analogous everolimus-eluting metallic stent (EES). The current analysis included all the patients recruited in the ABSORB Cohort B and SPIRIT II trials implanted with a single 3.0×18 mm device (Absorb BVS or EES) who underwent serial angiographic examinations at baseline and at two-year follow-up. The acute gain was defined as the difference between post- and preprocedural minimal lumen diameter (MLD). The in-stent/scaffold LLL was calculated as the difference in stent/scaffold segment between the post-procedural MLD and follow-up MLD. Thirty-three patients (33 lesions) implanted with the Absorb BVS, and 26 patients (28 lesions) implanted with the EES were studied. The acute gain was similar in the Absorb BVS group (1.23±0.38 mm) compared to the EES group (1.32±0.26 mm, p=0.29). The in-stent/scaffold LLL at two-year follow-up in the Absorb BVS group (0.26±0.19 mm) was also similar compared to the EES group (0.22±0.22 mm, p=0.29). Although the two groups had similar two-year clinical outcomes (major adverse cardiac events: Absorb BVS: 6.1% vs. EES: 0.0%), patients treated with the Absorb BVS exhibited a significantly lower two-year in-stent/scaffold MLD compared to the EES (2.02±0.26 mm vs. 2.22±0.34 mm, p=0.01). Although BVS and EES demonstrated similar two-year clinical outcomes, patients treated with the Absorb BVS exhibited a significantly lower two-year in-stent/scaffold MLD compared to patients treated with the EES. Appropriately powered randomised trials are necessary to confirm these exploratory results and evaluate their prognostic and clinical significance.