Target lesion revascularisation of bioresorbable metal scaffolds: a case series study and literature review

Magnesium-based resorbable scaffold vs permanent metallic sirolimus-eluting stent in patients with ST-segment elevation myocardial infarction: 3-year results of the MAGSTEMI randomised controlled trial

BACKGROUND

The long-term safety and performance of magnesium-based bioresorbable scaffolds (MgBRS) in ST-segment-elevation myocardial infarction (STEMI) patients are uncertain.

AIMS

The aim of this study was to report the 3-year clinical outcomes of the MAGSTEMI trial.

METHODS

This investigator-driven, multicentre, randomised, single-blind, controlled trial randomised STEMI patients 1:1 to MgBRS or to permanent metallic sirolimus-eluting stents (SES) at 11 academic centres. The main secondary endpoints included device-oriented composite endpoints (DoCE) and patient-oriented composite endpoints (PoCE), their individual components, any bleeding, and device thrombosis rate. All endpoints were defined according to the Academic Research Consortium. Events were adjudicated by an independent committee.

RESULTS

Three-year clinical follow-up was obtained in 142 (90.0%) patients. At 3-year follow-up, MgBRS were associated with a higher rate of DoCE than SES (13 [17.6%] vs 5 [6.6%], diff -11.0 [95% CI: -21.3 to -0.7]; p=0.038). This difference was driven by an increased incidence of DoCE within the first year of follow-up. In the landmark analysis, there was no difference between 1 and 3 years (0 [0.0%] vs 1 [1.4%]; p=1.000). The difference in the rate of DoCE was driven by a higher incidence of target lesion revascularisation (TLR) in the MgBRS group compared to SES (12 [16.2%] vs 4 [5.3%]; diff -10.9% [95% CI: -20.7 to -1.2]; p=0.030). The difference in TLR was observed during the first year, with no further differences observed between 1 and 3 years (0 [0.0%] vs 1 [1.4%]; p=1.000).

CONCLUSIONS

At 3-year follow-up, MgBRS were associated with a higher rate of TLR, which was clustered within the first year, compared to SES.

Procedural Results and One-Year Clinical Outcomes of Treatment of Bioresorbable Vascular Scaffolds Restenosis (from the RIBS VII Prospective Study)

Currently, both drug-eluting stents (DES) and drug-eluting balloons are recommended in patients with in-stent restenosis (ISR) of metallic stents. However, the clinical results of repeated interventions in patients with restenosis of bioresorbable vascular scaffolds (BVS) remain unsettled. We sought to assess the results of interventions in patients with BVS-ISR as compared with those obtained in patients with ISR of DES and bare-metal stents (BMS). Restenosis Intrastent: Treatment of Bioresorbable Vascular Scaffolds Restenosis (RIBS VII) is a prospective multicenter study (23 Spanish sites) that included 117 consecutive patients treated for BVS-ISR. Inclusion/exclusion criteria were similar to those of previous RIBS studies. Patients in the RIBS IV (DES-ISR, n = 309) and RIBS V (BMS - ISR, n = 189) randomized trials, were used as controls. Most patients with BVS-ISR were treated with DES (76%). Patients with BVS-ISR were younger, had larger vessels, and after interventions had higher in-segment residual diameter stenosis (19 ± 13%, 15 ± 11%, 15 ± 12%, p <0.001) than those treated for DES-ISR and BMS-ISR, respectively. At 1-year clinical follow-up (obtained in 100% of patients) target lesion revascularization (6%) was similar to that seen in patients with DES-ISR and BMS-ISR (8.7% and 3.7%, p = 0.32). Freedom from death, myocardial infarction, and target vessel revascularization (primary clinical end point) was 8.5%, also similar to that found in patients with DES-ISR and BMS-ISR (14.2% and 7.4%, p = 0.09). Results were also similar when only patients treated with DES in each group were compared and remained unchanged after adjusting for potential confounders in baseline characteristics. Time to BVS-ISR did not influence angiographic or clinical results. This study demonstrates the safety and efficacy of coronary interventions for patients presenting with BVS-ISR. One-year clinical results in these patients are comparable to those seen in patients with ISR of metallic stents (ClinicalTrials.gov ID:NCT03167424).

Bioresorbable magnesium scaffold in the treatment of simple coronary bifurcation lesions: The BIFSORB pilot II study

Objectives

To evaluate the feasibility, safety, and healing response of a magnesium‐based bioresorbable scaffold (BRS) in the treatment of simple bifurcation lesions using the single stent provisional technique.

Background

BRS may hold potential advantages in the treatment of coronary bifurcation lesions, however low radial strength and expansion capacity has been an issue with polymer‐based scaffolds. The magnesium BRS may prove suitable for bifurcation treatment as its mechanical properties are closer to those of permanent metallic drug‐eluting stents.

Methods

The study was a proof‐of‐concept study with planned inclusion of 20 patients with stable angina pectoris and a bifurcation lesion involving a large side branch (SB) > 2.5 mm with less than 50% diameter stenosis. Procedure and healing response were evaluated by optical coherence tomography (OCT). The main endpoints were a composite clinical safety endpoint and an OCT healing index at 1 month (range: 0–98).

Results

Eleven patients were included in the study. The study was prematurely terminated due to scaffold fractures and embolization of scaffold fragments in three cases requiring bailout stenting with drug‐eluting stents. One patient underwent bypass surgery at 3 months due to stenosis proximal to the study segment. All SB were patent for 1 month. One‐month OCT evaluation showed strut coverage of 96.9% and no malapposition. Scaffold fractures and uncovered jailing struts resulted in a less favorable mean OCT healing index score of 10.4 ± 9.0.

Conclusions

Implanting a magnesium scaffold by the provisional technique in nontrue bifurcation lesions was associated with scaffold fracture, embolization of scaffold fragments, and a high need for bailout stenting.

The resorbable magnesium scaffold Magmaris in acute coronary syndrome: An appraisal of evidence and user group guidance

Bioresorbable scaffolds provide transient vessel support without the long-term limitations of permanent metallic drug-eluting stents. The sirolimus-eluting resorbable magnesium scaffold Magmaris is the only CE-marked metallic bioresorbable scaffold and provides short-term lumen support before being completely bioresorbed. To date, clinical trial results have demonstrated low adverse event rates in patients with simple coronary lesions. Seven European centers with large experience in Magmaris implantation, combined efforts in an informal collaboration to evaluate and appraise clinical data currently available regarding the performance of Magmaris in patients presenting with acute coronary syndromes, and to supply user-advice on patient selection and optimal implantation practice.

Comparison of a Bioresorbable, Magnesium-Based Sirolimus-Eluting Stent with a Permanent, Everolimus-Eluting Metallic Stent for Treating Patients with Acute Coronary Syndrome: the PRAGUE-22 Study

Background

Magnesium-based bioresorbable Magmaris stents are rapidly resorbed. Few randomized studies have evaluated the efficacy of such stents in patients with acute coronary syndrome.

Aim

To investigate late lumen loss as assessed via quantitative coronary angiography (QCA) and optical coherence tomography (OCT) in patients with acute coronary syndrome treated with Magmaris stents or permanent, everolimus-eluting metallic Xience stents.

Methods and Results

This PRAGUE-22 study was a two-centre, investigator-initiated, randomized study. Fifty patients were randomized based on the inclusion criteria for acute coronary syndrome and the anatomical suitability to receive Magmaris or Xience stents. The patient characteristics did not differ between the Magmaris group (n = 25) and Xience group (n = 25). The mean ages were 57.0 ± 10.5 vs. 55.5 ± 9.2 years (p = 0.541) and the total implanted stent length was 24.6 ± 10.7 mm vs. 27.6 ± 11.1 mm (p = 0.368), respectively. Four clinical events occurred in the Magmaris group and one in the Xience group during 12 months of follow-up. The extent of late lumen loss (assessed via QCA) at 12 months was greater in the Magmaris group than in the Xience group (0.54 ± 0.70 vs. 0.11 ± 0.37 mm; p = 0.029). The late lumen loss diameter (measured via OCT) in the Magmaris group was also significantly larger than that in the Xience group (0.59 ± 0.37 vs. 0.22 ± 0.20 mm; p = 0.01).

Conclusion

Implantation of a magnesium-based bioresorbable stent in patients with acute coronary syndrome is associated with a greater extent of late lumen loss at the 12-month follow-up compared with implantation of a permanent, everolimus-eluting metallic stent.

Trial Registration: ISRCTN89434356