Mechanism of Drug-Eluting Absorbable Metal Scaffold Restenosis

Abstract

Background: The pathomechanisms underlying restenosis of the bioabsorbable sirolimus-eluting metallic scaffold (Magmaris) remain unknown. Using serial optical coherence tomography, we investigated causes of restenosis, including the contribution of late scaffold recoil versus neointimal hyperplasia. Methods: Patients enrolled in BIOSOLVE-II undergoing serial angiography and optical coherence tomography (post-intervention and follow-up: 6 months and/or 1 year) were analyzed. Patients were divided into 2 groups according to angiographic in-scaffold late lumen loss (LLL) <0.5 or ≥0.5 mm. End points were late absolute scaffold recoil and neointimal hyperplasia area as assessed by optical coherence tomography. Results: Serial data were available for analysis from 70 patients (LLL <0.5 mm: n=41; LLL ≥0.5 mm: n=29). Patient and lesion characteristics were comparable, and there was no significant difference in mean and minimal scaffold area between groups at post-intervention. Late absolute scaffold recoil was less among patients with LLL <0.5 mm (0.53±0.68 mm 2 ) compared with those with LLL ≥0.5 mm (1.48±1.20 mm 2 ; P <0.001). Neointimal hyperplasia area was smaller among patients with LLL <0.5 mm at follow-up (1.47±0.33 mm 2 ) compared with patients with LLL ≥0.5 mm (1.68±0.34 mm 2 ; P =0.013). In a matched-frame analysis (post-intervention and follow-up), late absolute scaffold recoil varied according to the underlying plaque type (lipid: 0.63±1.23 mm 2 ; calcified: 0.81±1.44 mm 2 ; and fibrous: 1.20±1.52 mm 2 ; P <0.001), while there was no difference with regards to neointimal hyperplasia area ( P =0.132). Conclusions: In addition to neointimal hyperplasia, late scaffold recoil contributed significantly to LLL of sirolimus-eluting absorbable metal scaffolds. The extent of late scaffold recoil was dependent on the underlying plaque morphology and was the highest among fibrotic lesions. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01960504.

Acute and one-year clinical outcomes of pre-stenting intravascular ultrasound: a patient-level meta-analysis of randomised clinical trials

“…Interestingly, half of the MgBRS restenosis was caused by scaffold collapse (Figure 6). In another OCT study that included 70 patients with MgBRS failure, the presence of late collapse was found as the main cause of late lumen loss, and device collapse was seen significantly more frequently in patients with fibrotic lesions [81]. These data suggest that future developments of MgBRS should focus on maintaining the radial force of the device for a longer period.…”

Optimal lesion preparation before implantation of a Magmaris bioresorbable scaffold in patients with coronary artery stenosis: Rationale, design and methodology of the OPTIMIS study

“…Even though long-term follow-up showed no scaffold thrombosis up to three years after implantation [ 5 , 31 ], observations of decrease in lumen area assessed with intravascular imaging over time [ 5 , 9 , 32 , 33 ] have raised questions about efficacy and concerns of higher restenosis rates compared to DES [ 6 , 7 , 9 ]. Due to lower radial strength of the MgBRS compared to DES, manipulation and repeated post-dilation after implantation may increase the risk of fracturing and dismantling of the BRS possibly leading to collapse and recoil [ 8 , 9 ]. It should be possible to avoid repeat post-dilatation after placement of the scaffold, if optimal lesion preparation is obtained.…”

“…Previous studies have shown that coronary lesions treated with early generation Magmaris BRS (Biotronik AG, Bülach, Switzerland) (MgBRS) resulted in lumen area reduction within the first year after implantation [ [5] , [6] , [7] ]. The exact mechanism is unclear, but increased plaque burden compromising the scaffold area, increased neointimal formation in the early phase of vascular healing, fast BRS resolution or constrictive remodeling have been considered as contributing factors [ 8 , 9 ]. Due to lower radial strength of the BRS compared to metal stents [ 10 ], repeat post-dilatation after implantation should be avoided, because of increased risk of dismantling causing BRS collapse and recoil.…”

Histopathology-Based Deep-Learning Predicts Atherosclerotic Lesions in Intravascular Imaging

“…OCT imaging was performed according to current recommendations ( 22 ) with commercially available OCT systems (Dragonfly DF-OCT-catheter combined with the C7-XRTM imaging system; LightLab Imaging Inc., Westford MA, USA). Pullbacks were assessed for the presence of atherosclerotic plaque features as previously described ( 23 ) and included fibrous, lipid and calcified plaques (see Table 2 ). A total of 222 frames from 51 patients were used for analysis.…”