Preserved endothelial vasomotor function after everolimus-eluting stent implantation

Coronary vasomotion after treatment with drug-coated balloons or drug-eluting stents: a prospective, open-label, single-centre randomised trial

BACKGROUND

Although recent studies have reported that drug-coated balloons (DCB) are non-inferior to drug-eluting stents (DES) for the treatment of native coronary arteries in a specific population, there is no available information concerning vasomotion after treatment with DCB.

AIMS

The aim of this study was to prospectively compare coronary vasomotion in patients with small coronary artery disease treated with DCB versus DES.

METHODS

Forty-two native lesions (2.0-3.0 mm) treated in our institution were randomly assigned to the DCB arm (n=19) or the bioabsorbable polymer everolimus-eluting stents arm (n=23) after successful predilation. At eight months after treatment, endothelium-dependent and -independent vasomotion was evaluated with intracoronary infusions in incremental doses of acetylcholine (right coronary artery: low dose 5 μg, high dose 50 μg; left coronary artery: low dose 10 μg, high dose 100 μg) and nitroglycerine (200 μg). The mean lumen diameter of the distal segment, beginning 5 mm and ending 15 mm distal to the edge of the treated segment, was quantitatively measured by angiography.

RESULTS

The luminal dimension in the treated segment did not differ between groups at the follow-up angiography. The vasoconstriction after acetylcholine infusion was less pronounced in the DCB arm than in the DES arm (low-dose: 6±13% vs -3±18%, p=0.060; high-dose: -4±17% vs -21±29%, p=0.035). The response to nitroglycerine did not differ between groups (17±13% vs 17±22%, p=0.929).

CONCLUSIONS

Vasoconstriction after acetylcholine infusion in the peri-treated region was less pronounced in the DCB arm than in the DES arm, suggesting that endothelial function in treated coronary vessels could be better preserved by DCB than by new-generation DES.

Coronary Endothelium-Dependent Vasomotor Function After Drug-Eluting Stent and Bioresorbable Scaffold Implantation

Background Early generation drug-eluting stents (DESs) showed a high grade of coronary endothelial dysfunction that was attributed to lack of stent reendothelialization. Endothelium-dependent vasomotor response of current DESs and bioresorbable scaffolds (BRSs) remains unknown. This study sought to assess the device-related endothelial function of current devices and to correlate neointima healing with endothelial function. Methods and Results A total of 206 patients from 4 randomized trials treated with the durable-polymer everolimus-eluting Xience (n=44), bioresorbable-polymer sirolimus-eluting Orsiro (n=35), polymer-free biolimus-eluting Biofreedom (n=24), bioactive endothelial-progenitor cell-capturing sirolimus-eluting Combo DES (n=25), polymer-based everolimus-eluting Absorb (n=44), and Mg-based sirolimus-eluting Magmaris BRS (n=34) underwent endothelium-dependent vasomotor tests and optical coherence tomography imaging, as per protocol, at follow-up. Crude vasomotor responses of distal segments to low-dose acetylcholine (10^-6 mol/L) were different between groups: bioresorbablepolymer DEShad the worst (-8.4%±12.6%) and durable-polymer DES had the most physiologic (-0.4%±11.8%; P=0.014). High-dose acetylcholine (10^-4 mol/L) showed similar responses between groups (ranging from -10.8%±11.6% to -18.1%±15.4%; P=0.229). Device healing was different between devices. Uncovered struts ranged from 6.3%±7.1% (bioresorbable-polymer DES) to 2.5%±4.5% (bioactive DES; P=0.056). In multivariate models, endothelium-dependent vasomotor response was associated with age, bioresorbable-polymer DES, and angiographic lumen loss, but not with strut coverage nor plaque type. Endothelial dysfunction (defined as ≥4% vasoconstriction) was observed in 46.6% of patients with low-dose and 68.9% with high-dose acetylcholine, without differences between groups. Conclusions At follow-up, endothelial dysfunction was frequently observed in distal segments treated with current stents without remarkable differences between devices. Although neointima healing was different between devices, poor healing was not associated with endothelial dysfunction.

Predictors of scaffold failure and impact of optimized scaffold implantation technique on outcome: Results from the German-Austrian ABSORB RegIstRy

AIMS

We aimed to investigate predictors of scaffold failure and the potential impact of an optimized scaffold implantation technique by means of a learning curve on long-term clinical outcome after bioresorbable scaffold (BRS) implantation and to evaluate predictors of scaffold failure.

METHODS AND RESULTS

A total of 3326 patients were included in this prospective, observational, multi-center study (ClinicalTrials.gov NCT02066623) of consecutive patients undergoing BRS implantation between November 2013 and January 2016. The 3144 patients completed follow-up after 24 months, 3265 patients were eligible for time-to-event-analysis. Clinical endpoints were major adverse cardiac events-a composite endpoint of death, target vessel revascularization and myocardial infarction, and scaffold thrombosis (ScT). Patients were grouped according to treatment before or since 2015. During follow-up MACE rate improved from 2.52% after 30 days, 5.45% after 6 months and 12.67% after 24 months to 1.52%, 3.44%, and 10.52%, respectively. A total of 75 ScT occurred. In multiple regression analysis, treatment of bifurcations, long lesions, and procedures performed earlier than 2014 were identified as predictors for the occurrence of ScT.

CONCLUSION

Treatment of bifurcation lesions is the strongest predictor of ScT following BRS implantation. A significantly lower incidence of ScT and 24-month target lesion revascularization in patients recruited after 2014 into our observational registry suggests the influence of a learning curve.

Acute Mechanical Performance of Magmaris vs. DESolve Bioresorbable Scaffolds in a Real-World Scenario

Background: After the bioresorbable PLLA-based vascular scaffold (Absorb BVS) was taken from the market due to its high adverse event rates, a magnesium-based scaffold (Magmaris) was introduced. Objective: To compare the acute performance of the sirolimus-eluting magnesium alloy Magmaris scaffold with that of the novolimus-eluting PLLA-based DESolve scaffold in terms of appropriate scaffold deployment using optical coherence tomography (OCT). Methods and Results: Data from the final OCT pullback of 98 patients were included (19 Magmaris, 79 DESolve) and analyzed 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. OCT showed a minimum lumen area for Magmaris vs. DESolve of 6.6 ± 1.6 vs. 6.0 ± 1.9 (p = 0.06). Scaffolds with residual area stenosis >20% were predominantly seen in the DESolve group (15.8 vs. 46.8%; p = 0.01). The mean eccentricity index did differ significantly (0.74 ± 0.06 vs. 0.63 ± 0.09; p < 0.001). No fractures were observed for Magmaris scaffolds, but 15.2% were documented for DESolve BRS (p < 0.001). Incomplete scaffold apposition area was significantly higher in the DESolve group (0.01 ± 0.02 vs. 1.05 ± 2.32 mm²; p < 0.001). Conclusion: This is the first study to compare the acute mechanical performance between Magmaris and DESolve in a real-world setting. The acute mechanical performance of Magmaris BRS seems to be superior to that of DESolve BRS, whereas OCT showed a good acute mechanical performance for both BRS in terms of generally accepted imaging criteria.

Coronary endothelial and microvascular function distal to polymer-free and endothelial cell-capturing drug-eluting stents. The randomized FUNCOMBO trial

INTRODUCTION AND OBJECTIVES

The vasomotor function of new-generation drug-eluting stents designed to enhance stent healing and reendothelialization is unknown. This study aimed to compare the endothelial function of the infarct-related artery (IRA) treated with bioactive circulating endothelial progenitor cell-capturing sirolimus-eluting stents (COMBO) vs polymer-free biolimus-eluting stents (BioFreedom) in ST-segment elevation myocardial infarction patients at 6 months. Secondary objectives were to compare the microcirculatory function of the IRA and stent healing at 6 months.

METHODS

Sixty patients were randomized to bioactive sirolimus-eluting stent vs polymer-free biolimus-eluting stents implantation. At 6 months, patients underwent coronary angiography with vasomotor, microcirculatory and optical coherence tomography examinations. Endothelial dysfunction of the distal coronary segment was defined as ≥ 4% vasoconstriction to intracoronary acetylcholine infusion.

RESULTS

Endothelial dysfunction was similarly observed between groups (64.0% vs 62.5%, respectively; P=.913). Mean lumen diameter decreased by 16.0 ±20.2% vs 16.1 ±21.6% during acetylcholine infusion (P=.983). Microcirculatory function was similar in the 2 groups: coronary flow reserve was 3.23 ±1.77 vs 3.23±1.62 (P=.992) and the index of microcirculatory resistance was 24.8±16.8 vs 21.3±12.0 (P=.440). Optical coherence tomography findings were similar: uncovered struts (2.3% vs 3.2%; P=.466), malapposed struts (0.1% vs 0.3%; P=.519) and major evaginations (7.1% vs 5.6%; P=.708) were observed in few cases.

CONCLUSIONS

Endothelial dysfunction of the IRA was frequent and was similarly observed with new-generation drug-eluting stents designed to enhance stent reendothelialization at 6 months. Endothelial dysfunction was observed despite almost preserved microcirculatory function and complete stent coverage. Larger and clinically powered studies are needed to assess the role of residual endothelial dysfunction in ST-segment elevation myocardial infarction patients. Registered in ClinicalTrials.gov: NCT04202172.

Coronary vasomotor function and myocardial flow with bioresorbable vascular scaffolds or everolimus-eluting metallic stents: a randomised trial

AIMS

The aim of this study was to compare the hyperaemic flow and vasomotor response to endothelium-dependent stimuli between bioresorbable vascular scaffolds (BVS) and metallic everolimus-eluting stents (EES) at 13 months.

METHODS AND RESULTS

Seventy non-diabetic patients aiming to achieve complete revascularisation were randomised 1:1 to BVS or EES implantation. At 13 months, invasive coronary angiography was performed using intracoronary pressure and Doppler ultrasound measurements at rest and maximal hyperaemia. A vasomotor test to endothelium-dependent (acetylcholine) and independent (nitroglycerine) stimuli and optical coherence tomography (OCT) were also performed. Fifty-nine patients (30 BVS and 29 EES) underwent 13-month examination. Doppler ultrasound average peak velocity (49.0±17.5 vs 49.3±18.3 cm/sec; p=0.95), coronary blood flow (97.4±53.5 vs 88.3±46.7 ml/min; p=0.51), coronary flow reserve (2.6±0.9 vs 2.7±0.8; p=0.84) and fractional flow reserve (0.92±0.06 vs 0.94±0.04; p=0.17) were similar between the groups. The vasomotor test showed vasoconstriction response to acetylcholine in 75.6% proximal and 72.2% distal peri-scaffold segments without differences between study devices. BVS had larger in-scaffold vasoconstriction than EES (60.0% vs 27.6%; p=0.01) despite similar neointima response as assessed by OCT.

CONCLUSIONS

BVS and EES had similar microcirculatory response to hyperaemia and predominant vasoconstrictive response in the peri-scaffold segments to endothelium-dependent stimuli. However, BVS exhibited larger vasoconstriction to endothelium-dependent stimuli in the scaffold segment.

Effect of Plaque Composition, Morphology, and Burden on DESolve Novolimus-Eluting Bioresorbable Vascular Scaffold Expansion and Eccentricity - An Optical Coherence Tomography Analysis

OBJECTIVE

This study of patients treated with novolimus-eluting bioresorbable scaffold (BRS) investigated the impact of plaque burden on the acute mechanical performance of the BRS and the short-term outcome.

METHODS

A total of 15 patients were enrolled. The following parameters were derived from optical coherence tomography (OCT) during the final pullback: mean and minimum area, residual area stenosis, incomplete strut apposition, tissue prolapse, scaffold expansion index (SEI), scaffold eccentricity index (SEC), symmetry index, strut fracture, and edge dissection. Fibrous plaque (FP) and calcific plaque (CP) characteristics were measured at each 200 μm longitudinal cross-section. The patients were divided into two groups based on their medians of the respective plaque characteristics.

RESULTS

OCT analysis showed a lumen area of 11.4 ± 1.9 mm² and a scaffold area of 11.5 ± 2.1 mm². The mean eccentricity index overall was 0.65 ± 0.16 and mean symmetry index 0.39 ± 0.25. Statistically, scaffold expansion was not significantly influenced by a greater plaque burden as represented by greater CP area (SEI in group with CP area <0.52 mm² 84.1% vs. SEI of 86.6% in group with CP area ≥0.52 mm², p = 0.06), thicker CP (85.7% vs. 85.1%, p = 0.06), greater CP arc angle (88.0% vs. 81.7%, p = 0.08), and CP being closer to the lumen (84.2% vs. 86.5%, p = 0.08). Scaffold expansion was also not significantly influenced by FP burden. The eccentricity of the implanted scaffolds was not dependent on the CP burden. On the other hand, a greater FP burden favoured a lower eccentricity index, indicating less circular expansion. Thus, greater FP area, FP thickness, and FP arc angle resulted in a more eccentric scaffold expansion.

CONCLUSION

In contrast to previously studied BRS, the expansion and eccentricity characteristics of the novolimus-eluting scaffold did not show the strong dependency of plaque composition, morphology, and burden. As assessed by OCT, only eccentricity was significantly affected by the FP burden. A greater FP plaque arc in our cohort and device-specific properties, e.g. self-correction, may explain the lack of a relationship between plaque, expansion, and eccentricity.

Multianalysis with optical coherence tomography and vasomotion in everolimus-eluting stents and everolimus-eluting biovascular scaffolds: the MOVES trial

Aims

To compare endothelium-dependent vasomotor function and vascular healing 15 months after implantation of two new-generation drug-eluting stents and biovascular scaffolds (BVS).

Methods and results

A total of 28 patients previously treated with a SYNERGY stent (bioabsorbable polymer everolimus-eluting stents (BP-EES)), a PROMUS stent (persistent polymer everolimus-eluting stents (PP-EES)) or an ABSORB (BVS) underwent control coronary angiography, 15 months after implantation, coupled with optical coherence tomography imaging and supine bicycle exercise. Intracoronary nitroglycerin was administered after exercise testing. Coronary vasomotor response was assessed using quantitative coronary angiography at rest, during supine bicycle exercise and after nitroglycerin. The primary end point was the percent change in mean lumen diameter compared with baseline. Secondary end points were strut coverage and apposition.There were no significant differences in vasomotor response between the three treatment groups. Patients with PP-EES showed significant vasoconstriction of the proximal peristent segment at maximum exercise (P=0.02). BP-EES (2.7%, 95% CI 0 to 5.5) and BVS (3.2%, 95% CI 0 to 6.7) showed less uncovered struts than PP-EES (12.1%, 95% CI 2.9 to 21.3, P=0.02 and 0.09, respectively). Complete strut apposition was more frequently seen with BP-EES (99.6%, 95% CI 99.2 to 100) than with BVS (98.9%, 95% CI 98.2 to 99.6, P=0.04) or PP-EES (95.0%, 95% CI 91.6 to 98.5, P=0.001).

Conclusion

BVS and thin strut BP-EES have a reassuring vasomotion profile, suggesting minimal endothelial dysfunction 15 months after implantation.

Potential therapeutic effects of mTOR inhibition in atherosclerosis

Despite significant improvement in the management of atherosclerosis, this slowly progressing disease continues to affect countless patients around the world. Recently, the mechanistic target of rapamycin (mTOR) has been identified as a pre-eminent factor in the development of atherosclerosis. mTOR is a constitutively active kinase found in two different multiprotein complexes, mTORC1 and mTORC2. Pharmacological interventions with a class of macrolide immunosuppressive drugs, called rapalogs, have shown undeniable evidence of the value of mTORC1 inhibition to prevent the development of atherosclerotic plaques in several animal models. Rapalog-eluting stents have also shown extraordinary results in humans, even though the exact mechanism for this anti-atherosclerotic effect remains elusive. Unfortunately, rapalogs are known to trigger diverse undesirable effects owing to mTORC1 resistance or mTORC2 inhibition. These adverse effects include dyslipidaemia and insulin resistance, both known triggers of atherosclerosis. Several strategies, such as combination therapy with statins and metformin, have been suggested to oppose rapalog-mediated adverse effects. Statins and metformin are known to inhibit mTORC1 indirectly via 5' adenosine monophosphate-activated protein kinase (AMPK) activation and may hold the key to exploit the full potential of mTORC1 inhibition in the treatment of atherosclerosis. Intermittent regimens and dose reduction have also been proposed to improve rapalog's mTORC1 selectivity, thereby reducing mTORC2-related side effects.

Comparison of endothelium-dependent and -independent vasomotor response after abluminal biodegradable polymer biolimus-eluting stent and persistent polymer everolimus-eluting stent implantation (COMPARE-IT)

BACKGROUND

Drug-eluting stents (DES) have been associated with local endothelial dysfunction in the segments proximal and distal to the stent (peristent segments) and increased thrombotic risk in long term follow-up. Little data exists on endothelial function post-implantation of new DES with biodegradable polymer. The aim of our study was to compare the local endothelial function assessed by exercise induced coronary vasomotion after implantation of a biolimus A9-eluting stent with biodegradable polymer (BES) with an everolimus-eluting stent with durable polymer (EES).

METHODS

Coronary vasomotion was evaluated with quantitative coronary angiography at rest and during supine bicycle exercise in nine patients with EES and thirteen patients with BES, 16 months after stent implantation. Mean luminal diameter of the stent, peristent segments, and of a control vessel were determined at rest, during exercise, and after the administration of nitroglycerine.

RESULTS

The control vessel showed exercise-induced vasodilatation in both groups (EES: +6.4±5.5%, p=0.07; BES: +7.8±10.1%, p=0.07). Vasomotion in the stented vessel segment was abolished. There was exercise-induced vasoconstriction in both groups in the segments proximal (EES: -9.6±4.5%; p=0.03; BES: -4.3±5.4%, p=0.02) and distal to the stent (EES: -3.2±9.3%; p=0.41, BES -8.6±8.0%, p<0.01). Sublingual nitroglycerin was associated with maximal vasodilatation of the peristent segments in both groups.

CONCLUSION

Alike DES with durable polymer, stents with a biodegradable polymer are associated with exercise-induced paradoxical coronary vasoconstriction of the peristent segments. This data suggests that endothelial dysfunction after DES implantation is not primarily caused by the durability of the polymer coating.