Five-Year Optical Coherence Tomography in Patients With ST-Segment–Elevation Myocardial Infarction Treated With Bare-Metal Versus Everolimus-Eluting Stents

High-Risk Culprit Plaque Predicts Cardiovascular Outcomes Independently of Plaque Rupture in ST-Segment Elevation Myocardial Infarction: Insight From Optical Coherence Tomography

The present study explored the predictive value of culprit high-risk plaque (HRP) detected by optical coherence tomography (OCT) for predicting major adverse cardiovascular events (MACEs) in patients with ST-segment elevation myocardial infarction (STEMI). HRP was defined as the simultaneous presence of four criteria: minimum lumen area <3.5 mm², fibrous cap thickness <75 μm, lipid plaque with lipid arc extension >180°, and presence of macrophages. Patients (n = 274) were divided into non-HRP group (n = 206) and HRP group (n = 68). MACEs were defined as a composite of all-cause death, myocardial infarction, stroke, and revascularization. During a mean follow-up of 2.2 years, 47 (17.5%) MACEs were observed: 28 (13.6%) in the non-HRP group and 19 (27.9%) in the HRP group (log-rank P = .005). Patients with HRP were 2.05 times more likely to suffer from a MACE than those without HRP (hazards ratio: 2.05, 95% confidence interval: 1.04-4.02, P = .038); MACE risk was comparable between plaque rupture and plaque erosion. In conclusion, HRP was present in 24.8% of STEMI patients and associated with higher cardiovascular risk independent of plaque rupture, suggesting that HRP detected by OCT may help identify patients at high risk of future cardiac events.

Effect of Parylene C on the Corrosion Resistance of Bioresorbable Cardiovascular Stents Made of Magnesium Alloy 'Original ZM10'

Magnesium (Mg) alloy has attracted significant attention as a bioresorbable scaffold for use as a next-generation stent because of its mechanical properties and biocompatibility. However, Mg alloy quickly degrades in the physiological environment. In this study, we investigated whether applying a parylene C coating can improve the corrosion resistance of a Mg alloy stent, which is made of 'Original ZM10', free of aluminum and rare earth elements. The coating exhibited a smooth surface with no large cracks, even after balloon expansion of the stent, and improved the corrosion resistance of the stent in cell culture medium. In particular, the parylene C coating of a hydrofluoric acid-treated Mg alloy stent led to excellent corrosion resistance. In addition, the parylene C coating did not affect a polymer layer consisting of poly(ε-caprolactone) and poly(D,L-lactic acid) applied as an additional coating for the drug release to suppress restenosis. Parylene C is a promising surface coating for bioresorbable Mg alloy stents for clinical applications.

10-Year Follow-Up of Patients With Everolimus-Eluting Versus Bare-Metal Stents After ST-Segment Elevation Myocardial Infarction

BACKGROUND

Outcomes data for a durable-polymer everolimus-eluting stent (EES) at extended long-term follow-up in patients with ST-segment elevation myocardial infarction (STEMI) are unknown.

OBJECTIVES

The aim of this study was to assess the 10-year outcomes of patients enrolled in the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-Segment Elevation Myocardial Infarction) trial.

METHODS

The EXAMINATION-EXTEND (10-Years Follow-Up of the EXAMINATION Trial) study is an investigator-driven 10-year follow-up of the EXAMINATION trial, which randomly assigned 1,498 patients with STEMI in a 1:1 ratio to receive either EES (n = 751) or bare-metal stents (n = 747). The primary endpoint was a patient-oriented composite endpoint of all-cause death, any myocardial infarction, or any revascularization. Secondary endpoints included a device-oriented composite endpoint of cardiac death, target vessel myocardial infarction, or target lesion revascularization; the individual components of the combined endpoints; and stent thrombosis.

RESULTS

Complete 10-year clinical follow-up was obtained in 94.5% of the EES group and 95.9% of the bare-metal stent group. Rates of the patient-oriented composite endpoint and device-oriented composite endpoint were significantly reduced in the EES group (32.4% vs. 38.0% [hazard ratio: 0.81; 95% confidence interval: 0.68 to 0.96; p = 0.013] and 13.6% vs. 18.4% [hazard ratio: 0.72; 95% confidence interval: 0.55 to 0.93; p = 0.012], respectively), driven mainly by target lesion revascularization (5.7% vs. 8.8%; p = 0.018). The rate of definite stent thrombosis was similar in both groups (2.2% vs. 2.5%; p = 0.590). No differences were found between the groups in terms of target lesion revascularization (1.4% vs. 1.3%; p = 0.963) and definite or probable stent thrombosis (0.6% vs. 0.4%; p = 0.703) between 5 and 10 years.

CONCLUSIONS

At 10-year follow-up, EES demonstrated confirmed superiority in combined patient- and device-oriented composite endpoints compared with bare-metal stents in patients with STEMI requiring primary percutaneous coronary intervention. Between 5- and 10-year follow-up, a low incidence of adverse cardiovascular events related to device failure was found in both groups. (10-Years Follow-Up of the EXAMINATION Trial; NCT04462315).

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.

Clinical significance of neoatherosclerosis observed at very late phase between 3 and 7 years after coronary stent implantation

BACKGROUND

Clinical significance of neoatherosclerosis (NA) observed at very late phase remains undetermined. We sought to investigate the association between NA observed by optical coherence tomography (OCT) 3-7 years after stenting and subsequent clinical outcomes.

METHODS

We investigated previously implanted stents without stent failure in the institutional OCT database at Tsuchiura Kyodo General Hospital. Qualitative and quantitative OCT analyses were performed. In patient-based analysis, major adverse cardiac events (MACE) included all-cause death, non-fatal myocardial infarction, and clinically driven revascularization. MACE-free survival rate was compared between patients with any stent showing NA (NA group) and those without NA (non-NA group). In stent-based analysis, the stent failure including target-lesion revascularization and stent thrombosis after the belated OCT examination were assessed.

RESULTS

A total of 187 patients with 308 stents undergoing belated OCT examination 3-7 years after implantation were investigated. Median duration from implantation to the belated OCT was 4.8 (3.8-5.8) years and NA was identified in 48 stents (15.6%) in 36 patients (19.3%). In patient-based analysis, during the median of 2.9 (2.1-3.6) years after belated OCT, MACE occurred in 9 patients (25.0%) with at least one stent showing NA (NA group) and 9 patients (6.0%) without NA (non-NA group) (p=0.002). Cox regression analysis revealed that NA was an independent predictor of MACE [hazard ratio (HR) 4.14 (1.58- 10.8), p=0.004]. In stent-based analysis, 7 stent failures were documented (stents with NA 10.0% vs. stents without NA 0.8%, p<0.01). NA was a significant predictor of stent failure [HR 9.17 (1.67- 50.3), p=0.011] at OCT examinations.

CONCLUSIONS

NA observed by OCT 3-7 years after implantation was associated with subsequent worse clinical outcomes in both patient-based and stent-based analysis.

Bioresorbable vascular scaffolds versus everolimus-eluting metallic stents in patients with ST-segment elevation myocardial infarction: 5-year results of the BVS-EXAMINATION study

AIMS

The aim of this study was to compare five-year clinical outcomes between an everolimus-eluting bioresorbable scaffold (BRS) and an everolimus-eluting metallic stent (EES) in STEMI patients.

METHODS AND RESULTS

This observational and retrospective study included 235 consecutive STEMI patients treated with BRS, compared with 235 STEMI patients treated with EES from the EXAMINATION trial, by applying propensity score matching. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction and target lesion revascularisation at five-year follow-up. Device thrombosis, according to the ARC criteria, was also evaluated. Optical coherence tomography (OCT) analysis was also performed at five years in event-free BRS patients. The cumulative incidence of five-year DOCE was higher in the BRS group as compared to the EES group (13.2% vs 7.6%, HR 1.87, 95% CI: 0.94-3.44, p=0.071), mainly driven by a higher rate of TLR (7.6% vs 1.7%, HR 1.15, 95% CI: 0.44-2.30, p=0.004). The five-year definite BRS thrombosis rate was also higher as compared to EES (4.2% vs 1.2%, HR 3.49, 95% CI: 0.95-12.82, p=0.054). OCT analysis showed a high incidence of neoatherosclerosis in the BRS group.

CONCLUSIONS

The five-year event risk was higher with BRS versus EES in STEMI. This suggests that the probability of obtaining favourable results at very long-term follow-up is low. Whether better results will be obtained with new-generation BVS remains to be determined.

Silk Fibroin as a Coating Polymer for Sirolimus-Eluting Magnesium Alloy Stents

Magnesium (Mg) alloy-based, bioresorbable scaffolding is a promising candidate for next-generation stents. Rapid corrosion of Mg alloy in the physiological environment, however, hinders its clinical application. Hydrofluoric acid (HF) treatment and biodegradable polymer coating have been widely reported to enhance corrosion resistance of the Mg alloy. Poor biocompatibility of biodegradable polymers, however, is known to promote adverse events such as intimal hyperplasia and thrombosis. We selected silk fibroin (SF) as the polymer for stent coating and evaluated drug release from the SF layer, corrosion resistance of the Mg alloy, and biocompatibility. After the stent was coated with SF, ethanol treatment of the SF layer enriched the β-sheet content. Release of sirolimus (SRL), a drug that prevents intimal hyperplasia, from the SF layer was slower than that with a poly(ε-caprolactone), the conventional biodegradable polymer used on medical devices. Ethanol treatment of the SF-coated stent further slowed SRL release from the SF layer. Crystalline domains in SF formed by the β-sheet structure could contribute to the slow release of SRL. The SF coating suppressed local and deep corrosion of the Mg alloy stent, although total corrosion remained unaffected. Uniform corrosion without local or deep corrosion prolongs the stent's radial strength. The SF coating showed excellent biocompatibility with human umbilical vein endothelial cells and minimal platelet adhesion. SF is expected to replace traditional biodegradable polymers for use on bioresorbable stents.

Recurrent atherosclerosis complications as a mechanism for stent failure

Stents are an indispensable tool in the percutaneous treatment of symptomatic coronary artery disease. Yet, stent failure due to restenosis or thrombosis may compromise their clinical benefit, carrying substantial morbidity and mortality. Despite improvements in device design and adjunctive medical treatment, stent failure still occurs during long-term follow-up, suggesting that this may be an issue that persists for many years, perhaps indefinitely. Numerous studies during the last decade have highlighted the previously underappreciated pivotal role of atherosclerosis in stent failure. We review evolving evidence on the role of atherosclerosis in stent restenosis and thrombosis, differentiating between de novo in-stent atherosclerosis development (i.e., neoatherosclerosis) and progression of pre-existing underlying atherosclerosis (i.e., paleoatherosclerosis), a distinction with potentially important clinical implications. We conclude with a concept that provides a unifying pathophysiology for these significant problems in the field of interventional cardiology based on the progression and destabilization of atherosclerosis.

Long-term clinical results of biodegradable vascular scaffold ABSORB BVS™ using the PSP-technique in patients with acute coronary syndrome

BACKGROUND

The PSP (predilatation, sizing, post-dilatation)-technique was developed to improve the prognosis of patients after bioresorbable vascular scaffold (BVS) implantation. In acute coronary syndrome (ACS) the use of BVS is particularly demanding and carries some potential risk regarding aggressive lesion preparation, proper vessel sizing due to spasm and thrombus inside the artery. The aim herein, was to determine the long-term results of BVS stenting in ACS patients depending on the scaffold implantation technique.

METHODS

The present study is a prospective, two-center study, which consisted of 182 patients who underwent percutaneous coronary intervention (PCI) with BVS (Absorb, Abbott Vascular, Santa Clara, California, USA) implantation for the ACS. All patients were divided into two groups. The first consisted of 52 patients treated with the PSP-technique (PSP group). The second group enrolled 130 patients treated with a non-PSP procedure (non-PSP group).

RESULTS

The procedure was successful in all patients. The mean observation time was 28.8 ± 16.5 months (median 28.3 months, interquartile range 24.0 [17.0-41.0] months). It was found that target vessel failure (TVF) was consistently reduced in patients using the PSP-technique as compared with the non-PSP group (5.8% vs. 17.7%, p = 0.03). Moreover, PSP-technique was superior to non-PSP-technique concerning major adverse cardiac events (MACE) (3.7% vs. 22.3%, p = 0.02). Logistic regression analysis revealed that the use of PSP technique significantly decreased the risk of target vessel revascularization (odds ratio [OR] 0.11, p = 0.01), TVF (OR 0.28, p = 0.03) and MACE (OR 0.29, p = 0.02).

CONCLUSIONS

The PSP-technique for BVS implantation improves long-term results and should also be recommended for newer generations of the bioresorbable scaffold.

A serial 3- and 9-year optical coherence tomography assessment of vascular healing response to sirolimus- and paclitaxel-eluting stents

Early-generation drug-eluting stents (DES) have been demonstrated to delay vascular healing. Limited optical coherence tomography (OCT) data on the very long-term neointimal response after DES implantation are available. The aim of this study was a serial OCT assessment of neointimal thickness, stent strut coverage, malapposition, and protrusion as markers of neointimal response at 3 and 9 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES). In this single-centre, longitudinal study consecutive patients undergoing elective PCI with SES or PES were included. OCT analysis was performed after 3 and 9 years by the independent core laboratory. A total of 22 subjects (8 SES and 14 PES) underwent an OCT assessment at 3 and 9 years post index procedure. The lumen, neointimal and malapposition area and the neointimal thickness (SES ∆50 µm, p = 0.195, PES ∆10 µm, p = 0.951) did not change significantly over the 6 year follow-up. No differences in the incidence of uncovered, malapposed or protruding struts were found in each type of stent. At 3 and 9 years after PCI, implantation of early-generation SES and PES may be associated with similar neointimal thickness, strut coverage, malapposition and protrusion, as assessed by serial OCT examination among patients with uneventful follow-up at 3 years post procedure. The small size of the study warrants judicious interpretation of our results and confirmation in larger multimodality imaging studies, including patients treated with contemporary stent platforms.

Impact of PSP Technique on Clinical Outcomes Following Bioresorbable Scaffolds Implantation

Bioresorbable scaffolds (BRS) were introduced in clinical practice to overcome the long-term limitations of newer-generation drug-eluting stents. Despite some initial promising results of the Absorb BRS, safety concerns have led to the discontinuation of the commercialization of this device. Several retrospective studies have assessed the impact of the so-called Pre-dilation, Sizing and Post-dilation (PSP) technique concluding that an optimal PSP technique can improve clinical outcomes following BRS implantation. In this article, the definition of the PSP technique, and the current evidence of its impact on clinical outcomes are put in perspective. Additionality, the relationship between the PSP technique and the dual-antiplatelet therapy to prevent scaffold thrombosis is addressed. Finally, the future perspectives of BRS technology in clinical practice are commented.

In Vivo Evaluation of the Synergic Effect of Metformin and mTOR Inhibitors on the Endothelial Healing of Drug-eluting Stents in Diabetic Patients

INTRODUCTION AND OBJECTIVES

Recent animal studies have shown metformin (MF) to impair endothelialization of drug-eluting stents (DES). The aim of this study was to evaluate the effect of MF on the healing of DES in human coronary arteries of patients with diabetes mellitus by optical coherence tomography (OCT).

METHODS

The RESERVOIR trial randomized 116 lesions in 112 patients with diabetes mellitus to amphilimus- or everolimus-eluting stents and included mandatory OCT at 9 months of follow-up. Patients were divided in 3 groups according to the glucose-lowering agents received: a) no MF; b) MF in noninsulin treated patients, and c) MF in insulin-treated patients. The primary safety endpoint was the rate of uncovered stents.

RESULTS

Seventeen patients with 19 lesions did not receive MF, whereas MF was administered to 53 noninsulin treated patients (54 lesions) and 28 insulin-treated patients (28 lesions). Baseline characteristics were comparable, although noninsulin treated patients who received MF had better glycemic control (P < .01). By OCT, rates of uncovered struts were comparable between groups (3.07±4.80% vs 2.23±4.73% vs 3.43±6.69%, respectively; P = .48). Multivariate models confirmed that MF had no effect on the healing of DES (OR, 1.49, 95%CI, 0.71-3.08; P = .29). Similarly, quantitative angiography showed no effect of MF on late lumen loss, whereas patients treated with exogenous insulin had greater late lumen loss (P = .02).

CONCLUSIONS

Metformin use does not impair endothelial healing of DES in patients with both insulin- and noninsulin-treated diabetes mellitus. According to these results, MF should not be discouraged in these patients.

Impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent: five-year follow-up optical coherence tomography study

The impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent (CoCrEES) remains unclear. We sought to evaluate them using optical coherence tomography (OCT). A total of 47 patients with 58 lesions treated only with CoCrEES and no target-vessel events within 5 years after implantation were prospectively enrolled and underwent 5-year follow-up OCT. Quantitative parameters and qualitative characteristics of the neointima were evaluated using multilevel logistic or linear regression models with random effects at three levels: lesion, cross-section (CS), and strut. According to the lesion complexity, the lesions were classified into the two groups: the complex lesion (CL) and non-CL group. The CL was defined as having at least 1 high-risk feature such as acute coronary syndrome lesion, lesion length > 20 mm, severe calcification requiring rotational atherectomy, and chronic total occlusion at the index procedure. A total of 11,034 struts (CL, n = 6240; non-CL, n = 4794) and 1202 (CL, n = 683; non-CL, n = 519) CSs were analyzed. The percentage of uncovered and malapposed struts did not differ significantly between the CL and non-CL groups (0.90 vs. 0.54%, P = 0.78; 0.56 vs. 0.10%, P = 0.16, respectively). The incidence of neoatherosclerosis was comparable between both groups in the CS- and lesion-level analysis (3.5 vs. 4.6%, P = 0.91; 32.0 vs. 24.2%, P = 0.52, respectively). At 5 years, CoCrEES shows an excellent vascular healing and similar frequency of neoatheroslerosis in patients without target-vessel events, regardless of the lesion complexity.

IVUS Findings in Late and Very Late Stent Thrombosis. A Comparison Between Bare-metal and Drug-eluting Stents

INTRODUCTION AND OBJECTIVES

Stent thrombosis (ST) is a life-threatening complication after stent implantation. Intravascular ultrasound is able to discern most causes of ST. The aim of this study was to compare intravascular ultrasound findings between bare-metal stents (BMS) and drug-eluting stents (DES) in patients with late (31 days to 1 year) or very late ST (> 1 year).

METHODS

Of 250 consecutive patients with late or very late ST in 7 Spanish institutions, 114 patients (45.5% BMS and 54.5% DES) were imaged with intravascular ultrasound. Off-line intravascular ultrasound analysis was performed to assess malapposition, underexpansion, and neoatherosclerosis.

RESULTS

The median time from stent implantation to ST was 4.0 years with BMS and 3.4 years with DES (P = .04). Isolated malapposition was similarly observed in both groups (36.5% vs 46.8%; P = .18) but was numerically lower with BMS (26.6% vs 48.0%; P = .07) in patients with very late ST. Isolated underexpansion was similarly observed in both groups (13.5% vs 11.3%; P = .47). Isolated neoatherosclerosis occurred only in patients with very late ST and was more prevalent with BMS (22.9%) than with DES (6.0%); P = .02. At 2.9 years' follow-up, there were 0% and 6.9% cardiac deaths, respectively (P = .06) and recurrent ST occurred in 4.0% and 5.2% of patients, respectively (P = .60).

CONCLUSIONS

Malapposition was the most common finding in patients with late and very late ST and is more prevalent with DES in very late ST. In contrast, neoatherosclerosis was exclusively observed in patients with very late ST and mainly with BMS.