Clinical presentation does not affect acute mechanical performance of the Novolimus-eluting bioresorbable vascular scaffold as assessed by optical coherence tomography

Introduction

Initial trials of bioresorbable vascular scaffolds (BVS) have mostly excluded patients presenting with acute coronary syndrome (ACS). However, these patients might benefit from a BVS platform, in particular as they are often younger and have been less frequently treated than patients with chronic disease.

Aim

To compare the acute performance of a Novolimus eluting BVS in ACS and non-ACS patients using optical coherence tomography (OCT) in patients presenting with acute or chronic coronary syndrome.

Material and methods

The final OCT pullback of 79 patients (34 with ACS, 45 non-ACS) was analysed at 1-mm intervals. The following indices were calculated: mean and minimal area, residual area stenosis, incomplete strut apposition, tissue prolapse, eccentricity index, symmetry index, strut fracture, and edge dissection.

Results

OCT showed a minimum lumen area (non-ACS vs. ACS) of 6.2 ±2.1 vs. 5.6 ±1.5 mm² (p = 0.21). Mean residual area stenosis was 14.5% vs. 19.5% (p = 0.39). The mean eccentricity index did not differ significantly (0.78 ±0.13 vs. 0.78 ±0.06; p = 0.42). There was a non-significant tendency for more fractures in the non-ACS group (22.2% vs. 5.9%; p = 0.07). Prolapse area was comparable (4.4 ±7.4 mm² vs. 5.2 ±10.9 mm²; p = 0.62).

Conclusions

This is the first study to investigate the acute mechanical performance of a Novolimus-eluting BVS in patients with different clinical presentations using OCT. We found that clinical presentation did not determine acute mechanical performance as assessed by the final OCT pullback. There was evidence of more mechanical complications in terms of fractures and a higher percentage of incomplete strut apposition in the group of patients with chronic coronary syndrome.

Influence of Plaque Characteristics on Early Vascular Healing in Patients With ST-Elevation Myocardial Infarction

OBJECTIVES

To compare the early vascular healing of ruptured plaques (RP) and non-ruptured plaques (NRP) one month after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI), using optical coherence tomography (OCT).

BACKGROUND

Vascular healing and strut coverage are important factors in reducing the risk of stent thrombosis after PCI. Influence of underlying lesion characteristics and differences in healing response between RP and NRP are unknown.

METHODS

Twenty-six STEMI-patients underwent PCI and implantation of a polymer-free drug-coated Biofreedom stent (BF-BES). OCT was performed pre-PCI, post-PCI and at 1-month follow-up. The patients were divided into two groups: RP = 15 and NRP = 11. OCT analyses of culprit lesion, post stent implantation at baseline and follow-up were performed to determine the difference in vascular healing based on presence of uncovered and/or malapposed stent struts and intraluminal filling defects.

RESULTS

The stent coverage did not differ significantly between the two groups at 1-month follow-up with percentage of uncovered struts: RP 26.5% [IQR 15.0-49.0] and NRP 28.1% [IQR 15.5-38.8] for NRP (p = 0.78). At 1-month, RP showed an increased percentage of late acquired malapposed struts (1.4% [IQR 0.8-2.4] vs. 0.0% [IQR 0.0-1.4], p = 0.03) and a larger total malapposition area (1.3 mm² [IQR 0.4-2.5] vs. 0.0 mm² [IQR 0.0-0.9], p = 0.01), compared to NRP.

CONCLUSION

Three out of four struts were covered within one month after stenting. The vascular healing was comparable in RP and NRP on stent coverage. However, RP had more and larger late acquired malapposition areas.

Intracoronary Imaging for Assessment of Vascular Healing and Stent Follow-up in Bioresorbable Vascular Scaffolds

Bioresorbable Vascular Scaffolds (BVS) are polymer-based materials implanted in the coronary arteries in order to treat atherosclerotic lesions, based on the concept that once the lesion has been treated, the material of the implanted stent will undergo a process of gradual resorption that will leave, in several years, the vessel wall smooth, free of any foreign material and with its vasomotion restored. However, after the first enthusiastic reports on the efficacy of BVSs, the recently published trials demonstrated disappointing results regarding long-term patency following BVS implantation, which were mainly attributed to technical deficiencies during the stenting procedure. Intracoronary imaging could play a crucial role for helping the operator to correctly implant a BVS into the coronary artery, as well as providing relevant information in the follow-up period. This review aims to summarize the role of intracoronary imaging in the follow-up of coronary stents, with a particular emphasis on the role of intravascular ultrasound and optical coherence tomography for procedural guidance during stent implantation and also for follow-up of bioabsorbable scaffolds.