Very Late Scaffold Thrombosis in Absorb BVS

The Absorb bioresorbable scaffold (BVS) (Abbott Vascular, Santa Clara, California) is a new, promising treatment option for coronary artery disease to overcome some limitations of metallic drug-eluting stents (DES) (1). Recently, concerns were raised regarding the occurrence of very late scaffold thrombosis (VLScT) in patients treated with BVS (2). The ABSORB II randomized controlled trial (RCT) reported 6 cases of VLScT among 335 patients at 3-year follow-up. None of these patients was using dual antiplatelet therapy (DAPT) at the time of VLScT (3). Two-year results from the ABSORB Japan RCT described 4 cases of VLScT; 2 of these patients had discontinued DAPT (4). These findings prompted us to locally investigate the occurrence of this very late thrombotic event and its potential relationship to DAPT termination. In our daily practice at 3 regional centers, we have also encountered cases of VLScT after discontinuation of DAPT. At 18 months, 3 of the 4 VLScT cases from a cohort of 685 patients receiving BVS seemed to be closely related to DAPT discontinuation. These thrombotic events occurred within 35 days following DAPT termination. Our findings, in combination with those from ABSORB II and ABSORB Japan RCT, are disturbing, and we believe need the attention of the medical community. A 60-year-old woman with dyslipidemia, hypertension, and history of percutaneous coronary intervention (PCI), presented with stable angina pectoris. Angiography revealed single-vessel disease of the RCA. Treatment consisted of pre-dilatation, implantation of 3 overlapping BVS, and post-dilatation. The patient used aspirin and clopidogrel for 369 days. Ten days later, she presented with ST-segment elevation myocardial infarction (STEMI) with visible thrombus on angiography, which was treated with thrombectomy, drug-eluting balloon, and abciximab. A 63-year-old man without cardiac risk factors was admittedwith a STEMI due to an occludedmid-left anterior descending coronary artery. After thrombectomy, he underwent primary PCI with 2 overlapping BVS and post-dilatation. Ticagrelor was stopped at day 381, and 35 days thereafter, he presented with STEMI due to VLScT. Intravascular imaging revealed frank thrombus and minimal malapposition. Thrombectomy, stenting with everolimus-eluting stent, and post-dilatation were performed. A 50-year-old womanwith positive family history for CAD and a current smoker was admitted to the hospital with a STEMI. After thrombectomy and pre-dilatation, she underwent PCI of the RCA with 1 BVS. Postprocedural optical coherence tomography (OCT) revealed malapposition and therefore, post-dilatation with a 4.0-mm balloon was performed reducing, but unfortunately not eliminating, malapposition. At day 449, then 20 days after prasugrel discontinuation, she returned with a Q-wave STEMI due to angiographically and OCT-proven ScT and malapposition. Treatment consisted of repeat PCI with thrombectomy, balloon angioplasty, and glycoprotein IIb/IIIa inhibitor. These cases are reported to draw attention to a problem that seems to be emerging: VLScT. In our cohort and in the ABSORB II trial, no VLScT occurred among patients continued on DAPT for a longer period of time. On the basis of this experience and previous publications (4), we encourage prolongation of DAPT beyond 12 months after implantation of BVS—as has been demonstrated to be efficient for high-risk DES-treated patients with a low bleeding risk (5). A DAPT score $2 seems optimal for current DES, whereas an increased risk of ischemic events for first-generation DES would warrant an additional point; and this could theoretically also apply for first-generation BVS. Extending DAPT even longer, to 30 months as investigated by the DAPT study in DES patients, will cover the majority of the period before the resorption process of BVS is completed. More data and dedicated studies are needed to confirm this recommendation. We believe that considering the inherent difference between BVS and metallic stents, specific DAPT recommendations are warranted for patients receiving BVS.