Impact of structural features of very thin stents implanted in unprotected left main or coronary bifurcations on clinical outcomes

Advancements in Coronary Bifurcation Stenting Techniques: Insights From Computational and Bench Testing Studies

Coronary bifurcation lesions present complex challenges in interventional cardiology, necessitating effective stenting techniques to achieve optimal results. This literature review comprehensively examines the application of computational and bench testing methods in coronary bifurcation stenting, offering insights into procedural aspects, stent design considerations, and patient-specific characteristics. Structural mechanics finite element analysis, computational fluid dynamics, and multi-objective optimization are valuable tools for evaluating stenting strategies, including provisional side branch stenting and two-stenting techniques. We highlight the impact of procedural factors, such as balloon positioning and rewiring techniques, and stent design features on the outcome of percutaneous coronary interventions with stents. We discuss the importance of patient-specific characteristics in deployment strategies, such as bifurcation angle and plaque properties. This understanding informs present and future research and clinical practice on bifurcation stenting. Computational simulations are a continuously maturing advance that has significantly enhanced stenting devices and techniques for coronary bifurcation lesions over the years. However, the accurate account of patient-specific vessel and lesion characteristics, both in terms of anatomical and accurate physiological behavior, and their large variation between patients, remains a significant challenge in the field. In this context, advancements in multi-objective optimization offer significant opportunities for refining stent design and procedural practices.

Comparison Among Ultra-Thin Coronary Stents: A Network Meta-Analysis

Ultrathin-strut drug-eluting stents (DES) have been related to potential improvement in stent-related outcomes compared with thicker-struts DES. However, comparisons among different ultrathin devices are lacking. All randomized controlled trials comparing ultrathin (struts thickness <70 µm) and thicker-struts DESs in an all-comers population were included. Target lesion failure (TLF), as defined by included trials, at 1-year follow-up was the primary end point. Overall mortality, myocardial infarction, target lesion revascularization (TLR), and stent thrombosis were the secondary end points. Arms of included trials were compared using network meta-analysis. Nine studies encompassing 20,081 patients were included, of which 9,509 patients had an ultrathin DES: Orsiro (evaluated in 7 arms with 8,086 patients), MiStent (1 arm with 703 patients), or Supraflex (1 arm with 720 patients). At 1-year follow-up, no significant differences were noted for TLF among these ultrathin DES. In particular, Orsiro was associated with a similar risk of TLF compared with Supraflex (risk rate 1.07, 95% confidence interval 0.59 to 1.78) and showed the highest probability of performing best in terms of TLF, myocardial infarction, and TLR. Ultrathin DES are all associated with a comparable risk of TLF compared with thicker-strut DES. In terms of TLR and TLF risk, Orsiro was the one with the highest probability of best performances, either compared with other ultrathin DES or to devices with thicker struts.

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

Duration and kind of dual antiplatelet therapy for acute coronary syndrome patients: a network meta-analysis

INTRODUCTION

For acute coronary syndrome (ACS) patients treated with percutaneous coronary intervention (PCI), the choice of the duration and kind of dual antiplatelet therapy (DAPT) offering the most accurate balance between ischemic and bleeding risk remains unknown.

EVIDENCE ACQUISITION

A network meta-analysis was performed including all Randomized Controlled Trials (RCTs) comparing different DAPT regimens and duration in ACS patients undergoing PCI. Trial-defined MACE and major bleedings were the primary endpoints. Stroke, stent thrombosis (ST), all-cause and cardiovascular death, myocardial infarction (MI) represented secondary endpoints.

EVIDENCE SYNTHESIS

13 RCTs encompassing 46145 patients were included. Mean age was 62 (61-64) years old, 42% being admitted with STEMI, 33% with NSTEMI and 25% with UA. The competitive arms were: clopidogrel and aspirin for 12 months (6 arms/18183 patients), clopidogrel and aspirin for 6 months (4/3329), clopidogrel and aspirin >12 months (3/2238), ticagrelor and aspirin for 12 months (6/12942) and prasugrel and aspirin for 12 months (3/9453). Trial-defined MACE and major bleedings, stroke and death were similar among the different arms. DAPT with prasugrel and aspirin for 12 months reduced MI compared to aspirin and clopidogrel for 12 months (OR 0.71, 95% CI: 0.54.0.94) and reduced the risk of ST compared to ticagrelor (OR 0.66, 95% CI: 0.49-0.90). Both prasugrel and ticagrelor reduced ST as compared to clopidogrel and aspirin for 12 months.

CONCLUSIONS

Different DAPT strategies yield similar risk of MACE, major bleeding, death and stroke in ACS patients. Prasugrel and aspirin for 12 months proved to be the most effective strategy regarding ST and MI.

Ultrathin Struts Drug-Eluting Stents: A State-of-the-Art Review

New-generation drug-eluting stents (DESs) represent the standard of care for patients undergoing percutaneous coronary intervention (PCI). Recent iterations in DES technology have led to the development of newer stent platforms with a further reduction in strut thickness. This new DES class, known as ultrathin struts DESs, has struts thinner than 70 µm. The evidence base for these devices consists of observational data, large-scale meta-analyses, and randomized trials with long-term follow-up, which have been conducted to investigate the difference between ultrathin struts DESs and conventional new-generation DESs in a variety of clinical settings and lesion subsets. Ultrathin struts DESs may further improve the efficacy and safety profile of PCI by reducing the risk of target-lesion and target-vessel failures in comparison to new-generation DESs. In this article, we reviewed device characteristics and clinical data of the Orsiro (Biotronik, Bülach, Switzerland), Coroflex ISAR (B. Braun Melsungen, Germany), BioMime (Meril Life Sciences Pvt. Ltd., Gujarat, India), MiStent (MiCell Technologies, USA), and Supraflex (Sahajanand Medical Technologies, Surat, India) sirolimus-eluting stents.

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

Impact of Left Ventricular Ejection Fraction on Procedural and Long-Term Outcomes of Bifurcation Percutaneous Coronary Intervention

The association of left ventricular ejection fraction (LVEF) with procedural and long-term outcomes after state-of-the-art percutaneous coronary intervention (PCI) of bifurcation lesions remains unsettled. A total of 5,333 patients who underwent contemporary coronary bifurcation PCI were included in the intercontinental retrospective combined insights from the unified RAIN (veRy thin stents for patients with left mAIn or bifurcatioN in real life) and COBIS (COronary BIfurcation Stenting) III bifurcation registries. Of 5,003 patients (93.8%) with known baseline LVEF, 244 (4.9%) had LVEF <40% (bifurcation with reduced ejection fraction [BIFrEF] group), 430 (8.6%) had LVEF 40% to 49% (bifurcation with mildly reduced ejection fraction [BIFmEF] group) and 4,329 (86.5%) had ejection fraction (EF) ≥50% (bifurcation with preserved ejection fraction [BIFpEF] group). The primary end point was the Kaplan-Meier estimate of major adverse cardiac events (MACEs) (a composite of all-cause death, myocardial infarction, and target vessel revascularization). Patients with BIFrEF had a more complex clinical profile and coronary anatomy. No difference in procedural (30 days) MACE was observed across EF categories, also after adjustment for in-study outcome predictors (BIFrEF vs BIFmEF: adjusted hazard ratio [adj-HR] 1.39, 95% confidence interval [CI] 0.37 to 5.21, p = 0.626; BIFrEF vs BIFpEF: adj-HR 1.11, 95% CI 0.25 to 2.87, p = 0.883; BIFmEF vs BIFpEF: adj-HR 0.81, 95% CI 0.29 to 2.27, p = 0.683). BIFrEF was independently associated with long-term MACE (median follow-up 21 months, interquartile range 10 to 21 months) than both BIFmEF (adj-HR 2.20, 95% CI 1.41 to 3.41, p <0.001) and BIFpEF (adj-HR 1.91, 95% CI 1.41 to 2.60, p <0.001) groups, although no difference was observed between BIFmEF and BIFpEF groups (adj-HR 0.87, 95% CI 0.61 to 1.24, p = 0.449). In conclusion, in patients who underwent PCI of a coronary bifurcation lesion according to contemporary clinical practice, reduced LVEF (<40%), although a strong predictor of long-term MACEs, does not affect procedural outcomes.

Polymer-free biolimus-eluting stents or polymer-based zotarolimus-eluting stents for coronary bifurcation lesions

BACKGROUND

A polymer-free biolimus-eluting stent (PF-BES) and a zotarolimus-eluting stent (ZES) recently showed similar clinical profiles and appear to be competing options in specific clinical settings of patients undergoing percutaneous coronary intervention (PCI). Whether they perform similarly also in complex procedural settings as coronary bifurcation lesions remains unaddressed.

METHODS

All consecutive patients undergoing coronary bifurcation PCI with PF-BES or the new iteration of the ZES from three large multicenter real-world registries were included. The primary outcome was major adverse cardiovascular events (MACE), a composite of all-cause death, myocardial infarction (MI), target lesion revascularization (TLR) and stent thrombosis (ST). Multiple analyses to adjust for baseline differences were carried out including propensity-score matching, propensity-score stratification and inverse-probability-weighting. Outcomes are reported according to Cox proportional hazard models censored at 400-day follow-up.

RESULTS

1169 patients treated with PF-BES (n = 440) or ZES (n = 729) on the main branch of a coronary bifurcation lesion were included (mean age 69 ± 11 years, 75.4% male, 53.8% acute coronary syndrome at presentation, 26.6% left main bifurcation, median dual antiplatelet therapy duration 12 [range 12-12] months). MACE, all-cause death, TLR and ST tended towards non-statistically higher rates with the PF-BES as compared to the ZES. Higher MI and target vessel revascularization occurrence was observed with PF-BES.

CONCLUSIONS

In this large contemporary cohort of patients undergoing coronary bifurcation PCI, the occurrence of MACE was non-statistically different with the use of PF-BES and ZES devices. However, differences favoring the ZES device that may entail clinical relevance were observed. Further studies are needed to confirm these findings and explore whether they remain valid when a short dual antiplatelet therapy is adopted.

Second generation drug-eluting stents: a focus on safety and efficacy of current devices

Introduction: Percutaneous coronary intervention (PCI) represents the most frequent procedure performed in medicine. Second generation drug eluting stents (DES) have been developed to reduce the rates of late and very late complications of first generation DES.Areas covered: To improve long-term efficacy and safety of patients undergoing PCI, second generation DES have been developed with novel stent platforms, biocompatible durable and biodegradable polymers and newer antiproliferative agents. In this review we provide an overview of second generation DES and their clinical trials, discussing safety and effectiveness of these devices, and outlining clinical indication for use.Expert commentary: Numerous clinical trials have demonstrated the safety and efficacy of second generation DES over the last decade. These devices represent the gold standard treatment in stable and acute coronary syndromes.

Accuracy of the PARIS score and PCI complexity to predict ischemic events in patients treated with very thin stents in unprotected left main or coronary bifurcations

BACKGROUND

The PARIS risk score (PARIS-rs) and percutaneous coronary intervention complexity (PCI-c) predict clinical and procedural residual ischemic risk following PCI. Their accuracy in patients undergoing unprotected left main (ULM) or bifurcation PCI has not been assessed.

METHODS

The predictive performances of the PARIS-rs (categorized as low, intermediate, and high) and PCI-c (according to guideline-endorsed criteria) were evaluated in 3,002 patients undergoing ULM/bifurcation PCI with very thin strut stents.

RESULTS

After 16 (12-22) months, increasing PARIS-rs (8.8% vs. 14.1% vs. 27.4%, p < .001) and PCI-c (15.2% vs. 11%, p = .025) were associated with higher rates of major adverse cardiac events ([MACE], a composite of death, myocardial infarction [MI], and target vessel revascularization), driven by MI/death for PARIS-rs and target lesion revascularization/stent thrombosis for PCI-c (area under the curves for MACE: PARIS-rs 0.60 vs. PCI-c 0.52, p-for-difference < .001). PCI-c accuracy for MACE was higher in low-clinical-risk patients; while PARIS-rs was more accurate in low-procedural-risk patients. ≥12-month dual antiplatelet therapy (DAPT) was associated with a lower MACE rate in high PARIS-rs patients, (adjusted-hazard ratio 0.42 [95% CI: 0.22-0.83], p = .012), with no benefit in low to intermediate PARIS-rs patients. No incremental benefit with longer DAPT was observed in complex PCI.

CONCLUSIONS

In the setting of ULM/bifurcation PCI, the residual ischemic risk is better predicted by a clinical risk estimator than by PCI complexity, which rather appears to reflect stent/procedure-related events. Careful procedural risk estimation is warranted in patients at low clinical risk, where PCI complexity may substantially contribute to the overall residual ischemic risk.

Contemporary coronary drug-eluting and coated stents: a mini-review

Percutaneous coronary intervention has become a standard-of-care procedure in patients with acute and chronic coronary syndromes, in which coronary stent technology is commonly used. In this mini-review article, we summarize the characteristics of contemporary coronary drug-eluting and coated stents.

Real-world reasons and outcomes for 1-month versus longer dual antiplatelet therapy strategies with a polymer-free BIOLIMUS A9-coated stent

BACKGROUND

A large trial established the favorable profile of a new polymer-free biolimus A9-eluting stent (PF-BES) with a 1-month dual antiplatelet therapy (DAPT) in high bleeding risk (HBR) patients. This is the first study comparing outcomes for a 1-month versus longer DAPT strategies following PF-BES-percutaneous coronary intervention (PCI).

METHODS

All patients undergoing PF-BES-PCI (January 2016 to July 2018) were included in the multicenter CHANCE registry. Patients were stratified according to DAPT strategy at discharge (planned 1-month vs. planned >1-month). Primary outcomes were the 390-day estimates of a patient-oriented and of a device-oriented composite endpoints (POCE: death, myocardial infarction [MI] or target vessel revascularization; DOCE: cardiac death, target vessel-MI or ischemia-driven target lesion revascularization). Landmark analyses from 1-month post-PCI were carried.

RESULTS

Following PF-BES-PCI, 328(40.3%) and 485(59.6%) patients were discharged with 1-month and longer DAPT (12 months [6-12]), respectively. Patients with a previous or index MI were less likely to be discharged on 1-month DAPT. Patients prescribed with 1-month DAPT were more likely to be at HBR than those with longer DAPT (90.2% vs. 69.9%, p = .001). No between-groups differences in the primary outcomes (planned 1-month vs. planned >1-month DAPT: POCE 11.9% vs. 13.2%, p = .747; DOCE: 4.8% vs. 8.1%, p = .500) were observed, also after adjusting for confoundings (POCE: adjusted-hazard ratio [adj-HR] 1.26, 95%CI 0.74-2.13; DOCE: adj-HR 1.00, 95%CI 0.49-1.99). Landmark analyses showed similar results.

CONCLUSIONS

In a large all-comers registry of PF-BES PCI, no interaction of planned DAPT strategy (1-month vs. >1-month) with outcomes was found. This observation warrants investigation in adequately powered randomized studies (ClinicalTrials.gov NCT03622203).

Early vascular response of ultra-thin bioresorbable polymer sirolimus-eluting stents assessed by optical frequency domain imaging: the EVALUATION study

This study aimed to evaluate the early vascular response of ultra-thin strut bioresorbable polymer sirolimus-eluting stents (BP SES) using optical frequency domain imaging (OFDI). Ultra-thin strut BP SES have superior outcomes in terms of efficacy and safety endpoints when compared to other thin strut new-generation stents. However, the factors contributing to the superiority of BP SES over other thin strut new-generation stents are unclear. A total of 32 patients with multivessel disease requiring staged procedures at 1 month were enrolled from 3 cardiovascular institutions; of these, 31 were immediately assessed by OFDI (n = 31). All patients were assessed at 1 month after ultra-thin strut BP SES implantation. The primary endpoint was % of uncovered struts. A total of 1723 cross sections (17,014 struts) were analyzed at baseline and 1 month after percutaneous coronary intervention. The % uncovered struts at 1-month follow-up was 7.7% (4.0, 13.8). Furthermore, the covered strut % (88.4% and 80.4%, P = 0.013) and malapposition rate (2.7% and 4.3%, P = 0.012) were significantly different between the 60-μm and 80-μm stents. Ultra-thin strut BP SES implantation may feasibly achieve early vascular responses due to the ultra-thin struts. This may ultimately lead to lower stent thrombosis and target lesion failure rates.Clinical trial registration University Hospital Medical Information Network Clinical Trials Registry (No. UMIN000033406).