A Randomized Comparison of Radial Artery Intimal Hyperplasia Following Distal Versus Proximal Transradial Access for Coronary Angiography: PRESERVE RADIAL

BACKGROUND

Distal transradial access (dTRA) is an alternative to conventional forearm transradial access (fTRA) for coronary angiography (CAG). Differences in healing of the radial artery (RA) in the forearm have not been evaluated between these 2 access strategies. We sought to compare the mean difference in forearm RA intimal-medial thickening (IMT) in patients randomized to dTRA versus fTRA.

METHODS AND RESULTS

In this single-center randomized clinical trial, 64 patients undergoing nonemergent CAG were randomized (1:1) to dTRA versus fTRA. Ultra-high-resolution (55-MHz) vascular ultrasound of the forearm and distal RA was performed pre-CAG and at 90 days. The primary end point was the mean change in forearm RA IMT. Secondary end points included procedural characteristics, vascular injury, RA occlusion, and ipsilateral hand pain and function. Baseline demographics and clinical characteristics, mean forearm RA IMT, and procedural specifics were similar between the dTRA and fTRA cohorts. There was no difference in mean change in forearm RA IMT between the 2 cohorts (0.07 versus 0.07 mm; P=0.37). No RA occlusions or signs of major vascular injury were observed at 90 days. Ipsilateral hand pain and function (Borg pain scale score: 12 versus 11; P=0.24; Disabilities of the Arm, Shoulders, and Hand scale score: 6 versus 8; P=0.46) were comparable.

CONCLUSIONS

Following CAG, dTRA was associated with no differences in mean change of forearm RA IMT, hand pain, and function versus fTRA for CAG. Further investigation is warranted to elucidate mechanisms and predictors of RA healing and identify effective strategies to preserving RA integrity for repeated procedures.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04801901.

Bare Metal Stents on Resveratrol-Coated Balloons in Porcine Coronary and Peripheral Arteries

Balloon angioplasty and stent implantation are standard techniques to reopen stenotic vessels. Often, balloons or stents coated with cytostatic drugs are used to prevent re-occlusion of the arteries. Resveratrol, which is known for its numerous beneficial effects on cardiovascular health, is used as an antioxidant additive on paclitaxel-coated balloon catheters. What is still unclear is whether resveratrol-only balloon coating in combination with a bare metal stent (BMS) also has positive effects on vascular healing. Here, we analyzed neointimal thickening, fibrin deposition, inflammation, vasa vasorum density, and reendothelialization after implantation of BMS via a resveratrol coated balloon approach in a porcine model. In general, resveratrol treatment did not result in significantly altered responses compared to the control group in peripheral arteries. In coronary arteries, an increase in vasa vasorum density became evident three days after resveratrol treatment compared to the control group and abolished up to day 7. Significant effects of the resveratrol treatment on the fibrin score or intima-media area were transient and restricted to either peripheral or coronary arteries. In conclusion, local single-dose resveratrol treatment via a resveratrol-only coated balloon and BMS approach did not lead to adverse systemic or local effects, but also no significant beneficial effects on vascular healing were detected in the current study.

Macrophage Polarization as a Novel Therapeutic Target for Endovascular Intervention in Peripheral Artery Disease

Peripheral artery disease (PAD) has a significant impact on human health, affecting 200 million people globally. Advanced PAD severely diminishes quality of life, affecting mobility, and in its most severe form leads to limb amputation and death. Treatment of PAD is among the least effective of all endovascular procedures in terms of long-term efficacy. Chronic inflammation is a key driver of PAD; however, stents and coated balloons eluting antiproliferative drugs are most commonly used. As a result, neither stents nor coated balloons produce durable clinical outcomes in the superficial femoral artery, and both have recently been associated with significantly increased mortality. This review summarizes the most common clinical approaches and limitations to treating PAD and highlights the necessity to address the underlying causes of inflammation, identifying macrophages as a novel therapeutic target in the next generation of endovascular PAD intervention.

Resveratrol-Coated Balloon Catheters in Porcine Coronary and Peripheral Arteries

Angioplasty aiming at vascular dilatation causes endothelial denudation and induces complex inflammatory responses that affect vascular healing, including delayed reendothelialization and excessive neointima proliferation. Resveratrol is known for multiple beneficial effects on the vessel wall after systemic treatment or sustained release from a stent. It is also used as an additive on drug-coated balloon catheters (DCB). In this study, the effect of a single dose of resveratrol, three days to four weeks after administration as a balloon coating during angioplasty, was investigated. Sixteen pigs underwent angioplasty with resveratrol-coated or uncoated balloon catheters in coronary and peripheral arteries. Vessels were overstretched by approximately 20% to enhance vessel wall injury and to produce persistent vessel wall irritation. A significantly reduced number of micro vessels and macrophages in the adventitia, as well as an improved reendothelialization of the vessel lumen, were observed in resveratrol-treated peripheral arteries. The coronaries had a much higher injury score compared to peripheral vessels. Resveratrol-dependent reduction of macrophages, micro vessels or acceleration of reendothelialization was not evident in the coronary vessels. Additionally, no significant effect on neointima proliferation and inflammation score in either vessel territory was observed as a result of resveratrol treatment. In conclusion, the results suggest that resveratrol diminishes the inflammatory response and promotes vascular healing in peripheral arteries. These same effects are absent in more severely injured coronary arteries.

Optical coherence tomography-guided versus angiography-guided implantation of everolimus-eluting bioresorbable vascular scaffolds: Comparison of coverage, apposition and clinical outcome. The ALSTER-OCT ABSORB registry

BACKGROUND

Suboptimal implantation of everolimus-eluting bioresorbable vascular scaffolds (EE-BVS) leading to strut malapposition and lack of neointima coverage has been hypothesized to be linked to late BVS-thrombosis. Optical coherence tomography (OCT) allows assessing subtle differences in BVS-healing. We aimed to link 6-months OCT-data on EE-BVS coverage and malapposition to implantation technique and clinical outcome.

METHODS

Twenty-nine consecutive EE-BVS-patients were included. EE-BVS-implantation was guided by angiography in the first 17 patients (group 1). Vessel sizing prior to implantation and implantation result was assessed by OCT in the 12 following patients (group 2). EE-BVS-implantation was performed in both groups with adequate lesion preparation, sizing and systematic high-pressure post-dilatation. All patients received 6-months invasive control including OCT-analysis and clinical follow-up for 2 years.

RESULTS

The rate of uncovered struts was group 1: 10.8 ± 10.0%; group 2: 10.6 ± 8.2%, p = 0.934. Target lesion failure due to BVS-thrombosis occurred in 2/17 patients at 9 and 18 months (11.8%, group 1), and no patients in group 2 (p = 0.218).

CONCLUSIONS

Optical coherence tomography analysis at 6-months following EE-BVS-implantation finds almost 90% of struts to be covered. No difference between OCT vs. angiography-guided EE-BVS-implantation was observed. OCT at 6-months was not able to predict late BVS-thrombosis of EE-BVS.

Magnetic Nanoparticle-Mediated Targeting of Cell Therapy Reduces In-Stent Stenosis in Injured Arteries

Although drug-eluting stents have dramatically reduced the recurrence of restenosis after vascular interventions, the nonselective antiproliferative drugs released from these devices significantly delay reendothelialization and vascular healing, increasing the risk of short- and long-term stent failure. Efficient repopulation of endothelial cells in the vessel wall following injury may limit complications, such as thrombosis, neoatherosclerosis, and restenosis, through reconstitution of a luminal barrier and cellular secretion of paracrine factors. We assessed the potential of magnetically mediated delivery of endothelial cells (ECs) to inhibit in-stent stenosis induced by mechanical injury in a rat carotid artery stent angioplasty model. ECs loaded with biodegradable superparamagnetic nanoparticles (MNPs) were administered at the distal end of the stented artery and localized to the stent using a brief exposure to a uniform magnetic field. After two months, magnetic localization of ECs demonstrated significant protection from stenosis at the distal part of the stent in the cell therapy group compared to both the proximal part of stent in the cell therapy group and the control (stented, nontreated) group: 1.7-fold (p < 0.001) less reduction in lumen diameter as measured by B-mode and color Doppler ultrasound, 2.3-fold (p < 0.001) less reduction in the ratios of peak systolic velocities as measured by pulsed wave Doppler ultrasound, and 2.1-fold (p < 0.001) attenuation of stenosis as determined through end point morphometric analysis. The study thus demonstrates that magnetically assisted delivery of ECs is a promising strategy for prevention of vessel lumen narrowing after stent angioplasty procedure.