Optimal Predilatation Treatment Before Implantation of a Magmaris Bioresorbable Scaffold In Coronary Artery Stenosis

Introduction: Ischemic heart disease (IHD) is characterized by progressive atherosclerosis in coronary arteries and may cause coronary artery stenosis or acute thrombus and occlusion. IHD is often treated with percutaneous coronary intervention (PCI) with balloon dilatation and implantation of a stent. The drug-eluting stents (DES) have been developed to minimize neointimal growth after implantation and reduce the risk of in-stent restenosis compared to bare-metal stents (BMS). Newer devices, bioresorbable scaffold (BRS), are made from a bioresorbable material slowly dissolving after implantation. The BRS guarantees optimal vessel support after balloon dilatation and implantation, but the artery can obtain original function and flexibility after the BRS has vanished. The development of the Magmaris BRS, with its improved radial strength, thinner struts compared to previous BRSs, is developed to reduce the complications seen in earlier generation BRS such as recoil, fracture and late stent thrombosis.

Previous studies have shown that coronary lesions treated with the previous generation of the Magmaris BRS resulted on lumen area reduction, possibly a consequence by increased plaque burden, compromising the scaffold area, combined with increased neointimal formation in the early phase of vascular healing and fast resolution.

Due to decreased radial strength of the BRS compared to metal stents, modification of plaque prior to BRS-implantation is necessary. The ScoreFlex balloon is a non-compliant balloon with circumference of fixated, scoring elements and permits controlled expansion and fragmentation of calcified plaque, compared to standard treatments with a non-compliant balloon.

Intravascular imaging with Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) can assess the morphology and location of plaques in the coronary stenosis prior to PCI thereby optimizing the implantation. The scaffold-treated segment can also be evaluated with intravascular imaging components such as stent coverage, malapposition and neointimal hyperplasia, but only if the scaffold is visible. If the scaffold is dissolved, another method to assess the vascular healing is needed. IVUS can evaluate change in elastic external membrane (EEM), change in remodeling and minimal lumen area (MLA). The reduction in MLA is associated with increased neointimal hyperplasia and plaque burden in the vessel wall.

The aim of the study is to investigate if lesion preparation with a ScoreFlex balloon compared to a standard non-compliant balloon improve vascular healing and minimize lumen reduction after implantation of a Magmaris bioresorbable scaffold.