In-Stent Stenosis After Surface-Modified Versus Uncoated Flow Diversion: a Randomized Trial (Derivo 2 Heal vs Derivo 2)

Background and Purpose Surface-modified flow diverters have been introduced to reduce thrombogenicity and potentially influence vascular healing. However, their impact on in-stent stenosis and aneurysm occlusion remains uncertain. We compared a coated flow diverter (Derivo 2 heal) with the corresponding uncoated device (Derivo 2) regarding in-stent stenosis development and aneurysm occlusion in a randomized clinical setting. Materials and Methods In this single-center randomized, open-label trial, 21 patients with unruptured internal carotid artery aneurysms were treated with either a coated ( n = 10) or uncoated ( n = 11) flow diverter. All patients received dual antiplatelet therapy and underwent digital subtraction angiography at 3 and 9 months. In-stent stenosis was assessed using a standardized ratio-based method. Device characteristics and oversizing were recorded. The presumed etiology of in-stent stenosis was categorized as intimal hyperplasia or stent deformity based on morphologic appearance. Results Mean in-stent stenosis at 3 and 9 months did not differ between groups. Complete aneurysm occlusion at 9 months was lower in the coated group (40.0% vs 81.8%; two-sided Fisher’s exact p = 0.080). Oversizing was not associated with in-stent stenosis but was numerically greater in patients with complete occlusion. Stent deformity was associated with higher in-stent stenosis than presumed intimal hyperplasia (3 months: 40.8% vs 21.7%, p = 0.007; 9 months: 30.1% vs 13.3%, p = 0.022). Conclusions In this randomized single-center study, the surface-modified Derivo 2 heal did not demonstrate reduced in-stent stenosis compared with the uncoated Derivo 2, while complete occlusion at 9 months was lower in the coated-device group. These findings warrant confirmation in larger comparative studies.