Myocardial Blood Flow and Coronary Flow Reserve During 3 Years Following Bioresorbable Vascular Scaffold Versus Metallic Drug-Eluting Stent Implantation

The randomized clinical VANISH (Impact of Vascular Reparative Therapy on Vasomotor Function and Myocardial Perfusion: A Randomized [15O]H2O PET/CT Study) trial was conducted to assess quantitative myocardial blood flow (MBF) during resting, hyperemia, and cold pressor testing (CPT) with positron emission tomographic perfusion imaging after the implantation of a bioresorbable everolimus-eluting scaffold compared with a drug-eluting stent.Long-term resorption of the bioresorbable everolimus-eluting scaffold reinstates normal vessel geometry, allowing natural regeneration of the newly formed endothelium with revival of vasomotor function.Sixty patients (18 to 65 years of age) with single-vessel disease and type A or B1 lesions were randomized in a 1-to-1 fashion. Approximately 1 month, 1 year, and 3 years after device implantation, patients underwent [15O]H2O cardiac positron emission tomography. The primary endpoint was the interaction of device type and evolution over time of hyperemic MBF, coronary flow reserve, or CPT reserve. At 3-year follow-up, control invasive coronary angiography with optical coherence tomography was performed.Fifty-nine (98%), 56 (93%), and 51 (85%) patients successfully completed 1-month, 1-year, and 3-year follow-up positron emission tomography, respectively, and no culprit vessel events were registered during follow-up time. The primary study endpoint (i.e., interaction between device type and time) was nonsignificant for hyperemic MBF, CPT reserve, and coronary flow reserve (p > 0.05 for all). In all patients, hyperemic MBF decreased from 1 to 3 years (p = 0.02), while coronary flow reserve was lower at 3-year follow-up compared with 1-month and 1-year follow-up (p = 0.03 for both). After 3 years, percentage area stenosis measured with optical coherence tomography was higher within the bioresorbable everolimus-eluting scaffold compared with the drug-eluting stent (p = 0.03).The hypothesized beneficial effects of scaffold resorption did not translate to improved MBF during maximal hyperemia or endothelium-dependent vasodilation by CPT.