Very late Magmaris scaffold restenosis: a 6-year serial optical coherence tomography case report.

Background: Bioresorbable scaffolds (BRS) have been proposed as an alternative to drug-eluting stents (DES), offering radial support during the early phases of healing, while potentially reducing the risk of long-term complications. A magnesium-based BRS (MgBRS) has shown promising results after implantation. However, there is a lack of knowledge regarding the long-term outcomes. Case summary: A 62-year-old man with hypertension, dyslipidaemia, family history of ischaemic heart disease, and previous myocardial infarction, presented with non-ST-elevation myocardial infarction (NSTEMI). Six years prior, he also had a NSTEMI and a mid-left anterior descending artery (LAD) lesion was treated with a 3.0/25 mm MgBRS. Post-implantation optical coherence tomography (OCT) revealed proximal edge dissection, and a second MgBRS 3.0/15 mm was implanted. Optical coherence tomography of the scaffold-treated segment was performed after 6 and 12 months with no sign of restenosis. The current angiogram showed a restenosis in the previously MgBRS-treated segment in LAD. Optical coherence tomography showed a plaque rupture in a thin cap fibro-atheroma and scaffold remnants. The lesion was pre-dilated and stented with a 3.0/20 mm DES and post-dilated with a 3.5 mm non-compliant balloon. Discussion: Most cases of late scaffold failure showed acquired mal-apposition, which also can be related to the degrading process, or uncovered struts, none of which were seen in our case at 6 or 12 months. This case represents an insight into the vascular healing and potential mechanisms for failure of the MgBRS, with serial OCT recording at implantation, and after 6 months, 12 months, and 6 years.

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

Introduction: Percutaneous coronary intervention with implantation of a bioresorbable scaffold (BRS) provide the vessel support for a limited period allowing the vessel to restore normal vasomotion after degradation of the BRS, opposed to treatment with drug-eluting stents where the metal persist in the vessel wall. Late lumen loss and reduction in lumen area after implantation have been reported. The purpose of this study was to investigate whether intense pre-dilatation before BRS implantation resulted in less reduction of minimal lumen area at 6- and 12-month follow-up after implantation of a Magmaris BRS (MgBRS). Coronary imaging with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) was assessed to track changes in lumen and vessel dimensions. Methods: The prospective Optimal lesion PreparaTion before Implantation of the Magmaris bioresorbable scaffold In patients with coronary artery Stenosis (OPTIMIS) study randomly assigned eighty-two patients with chronic coronary syndrome to two pre-dilatation treatment strategies. Patients were randomized in a 1:1 ratio to pre-dilatation with either a non-compliant scoring balloon or a standard non-compliant balloon prior to implantation of a MgBRS. The treated segment was evaluated with OCT and IVUS at baseline, after 6 and 12 months to assess changes in lumen and vessel dimensions. The hypothesis was that more intense pre-dilatation with a non-compliant scoring balloon before MgBRS implantation can reduce the risk of late lumen reduction compared to standard pre-dilatation. The power calculation used expected MLA after 6 months (6.22 mm2 for the scoring balloon and 5.01 mm2 for the standard non-compliant balloon), power of 80 %, significance level of 0.05 and expected drop-out rate of 15 %, requiring 82 patients to be enrolled. Results: Eighty-two patients were included in the study. Enrollment was from December 2020 to September 2023. Conclusion: The hypothesis was that more intense pre-dilatation with a non-compliant scoring balloon before MgBRS implantation can reduce the risk of late lumen reduction compared to standard pre-dilatation.

The Influence of Microcirculatory Dysfunction on the Resting Full Cycle Ratio Compared to Fractional Flow Reserve.

BACKGROUND: The relation between the resting full cycle ratio (RFR) and fractional flow reserve (FFR) is not fully understood. This study aims to investigate the influence of coronary microvascular dysfunction, assessed by the index of microvascular resistance (IMR), on RFR compared to FFR in patients undergoing functional assessment for coronary stenosis. MATERIALS AND METHODS: Two-hundred patients with borderline stenosis underwent functional assessment of RFR, FFR, coronary flow reserve (CFR) and IMR. Retriever operator curve analysis was performed to assess the diagnostic value of RFR in patients with (IMR ≥ 24) and (IMR < 24). RESULTS: Median RFR did not differ significantly in patients with IMR ≥ 24 compared to patients with IMR < 24: 0.89 (interquartile range (IQR) 0.84, 0.95) vs. 0.90 (IQR 0.84, 0.92), p = 0.29). FFR was significantly higher in patients with IMR ≥ 24 compared to patients with IMR < 24: median FFR 0.85 (IQR (0.76, 0.92)) vs. 0.82 (IQR 0.73, 0.86), p = 0.009, and median CFR was significantly lower 1.80 (IQR 1.40, 2.55) vs. 2.70 (IQR 1.80, 3.95), p < 0.001. The diagnostic value of RFR was high (Area under the curve (AUC) 0.89 95 % Confidence Interval: [0.85, 0.93]) and AUC did not differ between patients with IMR ≥ 24 compared to patients with IMR < 24: 0.89 vs. 0.90, p = 0.89. An overall optimal cut off of 0.88 was identified. The cut off did not differ significantly between patients with IMR ≥ 24 compared to patients with IMR < 24: 0.88 vs. 0.90, p = 0.397. CONCLUSION: In patients with coronary borderline stenosis, the coronary microvascular function did not influence on the cut off values or AUC of RFR compared to FFR.