Revascularization With BVS or CABG in Patients With Advanced CAD

Coronary artery disease (CAD) is the leading cause of death among adult population in developed countries. Optimal method of revascularization of patients with multivessel CAD is still the matter of debate. Currently, there are two recognized methods: percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Both methods were compared in a number of studies, including several randomized trials. Most trials have left some doubts. First of all, none of them used functional evaluation of the stenosis. The decision regarding revascularization was based on angiographic results alone. The trials that have used fractional flow reserve (FFR) show no clear correlation between the degree of stenosis assessed angiographically, in the range of 50-90%, and its functional significance. In a randomized FAME trial, out of 1329 significant stenosis assessed anatomically, nearly 40% revealed no functional significance. The study showed that coronary revascularization guided by FFR in multivessel stable CAD resulted in a smaller number of vessels stented, and hence fewer stent implantations. Such a strategy has improved patient clinical outcomes. In the group of patients undergoing revascularization based on fractional flow reserve significant reduction in major adverse cardiac events (MACE) was observed in 1- and 2-year follow up.

Another weakness of former studies was the use of first-generation drug eluting stent (DES) showing an increased risk of restenosis and late and very late stent thrombosis. Many randomized studies documented superiority of new generation DES, with more biocompatible or bioresorbable polymer in terms of the incidence of MACE (SPIRIT, LEADERS). Recently, fully bioresorbable vascular scaffolds (BVS) have been introduced into routine clinical practice. Preliminary results of the ABSORB EXTEND trial demonstrated similar efficacy and safety of the Absorb BVS, as compared with the best-in-class its metallic counterpart XIENCE. Since the complete resorption of the scaffold requires two-three years, the greatest clinical benefit will be observed a couple of years after implantation. Total bioresorption of the scaffold not only allows to restore the physiological function of the vessel, but also eliminates a number of adverse events associated with the presence of permanent metallic prosthesis in the vessel wall, such as very late stent thrombosis and the neo-atherosclerosis development.

Intravascular imaging with intravascular ultrasound (IVUS) or optical coherence tomography (OCT) is widely considered the gold standard for scaffold optimal implantation, although currently it is not routinely used. The use of intravascular imaging techniques before and after BVS implantation may help to avoid inadequate expansion and apposition of the scaffold struts. Subintimal calcifications detected with IVUS or OCT require adequate lesion preparation before stent deployment. This is particularly crucial for patients receiving BVS, where the goal of lesion preparation is to facilitate scaffold delivery, reduce plaque shift and to allow optimal scaffold expansion. OCT with its greater resolution enables to assess the scaffold integrity, apposition and the presence of thrombus or edge dissections.

Based on the ABSORB EXTEND trial there are some suggestions for longer dual antiplatelet therapy duration and more potent agents than clopidogrel (i.e. ticagrelor) regardless of clinical presentation, particularly in the first months after BVS implantation. Ticagrelor in the PLATO trial has been shown to reduce the rate of a combined endpoint of cardio-vascular death, myocardial infarction, or stroke compared to clopidogrel. In patients treated with PCI, it also reduces the rate of stent thrombosis. Statins are the most widely used LDL-lowering drugs in high-risk patients. It is recommended to achieve a greater than 50% reduction in LDL levels. Treatment goal for fasting LDL-cholesterol is < 70 mg/dl (1.8 mmol/l). In comparison with other lipid-lowering agents, rosuvastatin is the most potent agent to achieve the required reduction of LDL. Rosuvastatin in maximal tolerated dose is indicated to reduce the risk of myocardial infarction and revascularization procedures.

RELEASE-BVS study is the first trial that takes into account all of the following important aspects:

• stable advanced coronary artery disease: 3-vessel disease or significant left main (LM) stenosis, suitable for either PCI or CABG with proven ischemia in stress CMR;
• coronary revascularization (PCI) guided by functional assessment of stenosis (iFR/FFR);
• the use of a bioresorbable everolimus-eluting scaffolds (Absorb) and PCI optimization with intracoronary imaging techniques (OCT);
• long-term post-procedural management with potent antiplatelet drug (ticagrelor) and optimal lipid-lowering therapy with maximal tolerated dose of rosuvastatin.