Small Vessel Coronary Artery Disease: Rationale for Standardized Definition and Critical Appraisal of the Literature

Definitions and standardized endpoints for the use of drug-coated balloon in coronary artery disease: consensus document of the Drug Coated Balloon Academic Research Consortium

The Drug Coated Balloon Academic Research Consortium project originated from the lack of standardization and comparability between studies using drug-coated balloons in the treatment of obstructive coronary artery disease. This document is a collaborative effort between academic research organizations and percutaneous coronary intervention societies in Europe, the USA, and Asia. This consensus sought to standardize study designs and endpoints for clinical trials involving drug-coated balloons, including defining angiographic, intravascular, and non-invasive imaging methods for lesion assessment, alongside considerations for post-revascularization pharmaco-therapy. The concept of 'blended therapy', which advocates for combining device strategies, is also discussed. This paper delineates study types, endpoint definitions, follow-up protocols, and analytical approaches, aiming to provide consistency and guidance for interventional cardiologists and trialists.

Stepwise dual antiplatelet therapy de-escalation in patients after drug coated balloon angioplasty (REC-CAGEFREE II): multicentre, randomised, open label, assessor blind, non-inferiority trial

OBJECTIVES

To investigate whether a less intense antiplatelet regimen could be used for people receiving drug coated balloons.

DESIGN

Multicentre, randomised, open label, assessor blind, non-inferiority trial (REC-CAGEFREE II).

SETTING

41 hospitals in China between 27 November 2021 and 21 January 2023.

PARTICIPANTS

1948 adults (18-80 years) with acute coronary syndrome who received treatment exclusively with paclitaxel-coated balloons according to the international drug coated balloon consensus.

INTERVENTIONS

Participants were randomly assigned (1:1) to either the stepwise dual antiplatelet therapy (DAPT) de-escalation group (n=975) consisting of aspirin plus ticagrelor for one month, followed by five months of ticagrelor monotherapy, and then six months of aspirin monotherapy, or to the standard DAPT group (n=973) consisting of aspirin plus ticagrelor for 12 months.

MAIN OUTCOME MEASURES

The primary endpoint was net adverse clinical events (all cause death, stroke, myocardial infarction, revascularisation, and Bleeding Academic Research Consortium (BARC) type 3 or 5 bleeding) at 12 months in the intention-to-treat population. Non-inferiority was established if the upper limit of the one sided 95% confidence interval (CI) for the absolute risk difference was smaller than 3.2%.

RESULTS

The mean age of participants was 59.2 years, 74.9% were men, 30.5% had diabetes, and 20.6% were at high bleeding risk. 60.9% of treated lesions were in small vessels, and 17.8% were in-stent restenosis. The mean drug coated balloon diameter was 2.72 mm (standard deviation 0.49). At 12 months, the primary endpoint occurred in 87 (8.9%) participants in the stepwise de-escalation group and 84 (8.6%) in the standard group (difference 0.36%; upper boundary of the one sided 95% CI 2.47%; Pnon-inferiority=0.013). In the stepwise de-escalation versus standard groups, BARC type 3 or 5 bleeding occurred in four versus 16 participants (0.4% v 1.6%, difference -1.19% (95% CI -2.07% to -0.31%), P=0.008), and all cause death, stroke, myocardial infarction, and revascularisation occurred in 84 versus 74 participants (8.6% v 7.6%, difference 1.05% (95% CI -1.37% to 3.47%), P=0.396). Treated as having hierarchical clinical importance by the win ratio method, more wins were noted with the stepwise de-escalation group (14.4% wins) compared with the standard group (10.1% wins) for the predefined hierarchical composite endpoint of all cause death, stroke, myocardial infarction, BARC type 3 bleeding, revascularisation, and BARC type 2 bleeding (win ratio 1.43 (95% CI 1.12 to 1.83), P=0.004). Results from the per-protocol and the intention-to-treat analysis were similar.

CONCLUSIONS

Among participants with acute coronary syndrome who could be treated by drug coated balloons exclusively, a stepwise DAPT de-escalation was non-inferior to 12 month DAPT for net adverse clinical events.

TRIAL REGISTRATION

Clinicaltrials.gov NCT04971356.

Comparative efficacy and safety of drug-coated balloons versus drug-eluting stents in small vessel coronary artery disease: an updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Small vessel coronary artery disease presents challenges in percutaneous coronary intervention due to higher restenosis rates with traditional treatments. Drug-coated balloons (DCBs) offer a potential alternative, but their efficacy compared to drug-eluting stents (DES) remains debated. This meta-analysis aims to provide updated insights into the comparative outcomes of DCBs versus DES in small coronary artery disease.

MAIN TEXT

Following PRISMA guidelines, a systematic review identified seven randomized controlled trials (RCTs) comparing DCBs with DES for small vessel CAD. Data were extracted and pooled for analysis, assessing outcomes including target lesion revascularization (TLR), target vessel revascularization (TVR), mortality, myocardial infarction (MI), stent/vessel thrombosis, and major adverse cardiovascular events (MACE). Statistical analysis was performed using RevMan version 5.4, employing random-effects models and forest plots with odds ratios (OR) and 95% confidence intervals (CI). Among 1,808 patients across seven RCTs, no significant difference was found in TVR between DCB and DES over 3 years (OR = 0.95, 95% CI [0.58, 1.54], p = 0.82). While initial analyses favoured higher TLR incidence in DES, the trend shifted towards DCB over time, with a non-significant association favouring DCB at 3 years (OR = 0.51, 95% CI [0.26, 1.00], p = 0.05). DCB use was associated with significantly higher rates of MACE and MI at the 3-year mark (MACE: OR = 0.55, 95% CI [0.38, 0.79], p = 0.001; MI: OR = 0.35, 95% CI [0.17, 0.7], p = 0.003), while mortality rates converged between the two interventions over time. Vessel thrombosis rates were similar between DCB and DES.

CONCLUSIONS

While DCBs may offer comparable efficacy to DES in terms of TVR and TLR over shorter durations, there is a concerning trend towards higher rates of MACE and MI associated with DCB use at the 3-year mark. Further research with larger sample sizes, longer follow-up durations, and consistent inclusion criteria is needed to elucidate the optimal treatment strategy for small vessel CAD. Until then, DES may be considered a safer option for managing small vessel CAD.

Template-Assisted Electrospinning and 3D Printing of Multilayered Hierarchical Vascular Grafts

Fabricating complex hierarchical structures mimicking natural vessels and arteries is pivotal for addressing problems of cardiovascular diseases. Various fabrication strategies have been explored to achieve this goal, each contributing unique advantages and challenges to the development of functional vascular grafts. In this study, a three-layered tubular structure resembling vascular grafts was fabricated using biocompatible and biodegradable copolymers of poly(butylene succinate) (PBS) using advanced manufacturing techniques. The outer layer was fabricated by template-assisted electrospinning utilizing a 3D-printed scaffold with a precise hexagonal pore design as the template, and the inner layer was coated with gelatin through perfusion. Cellulose nanocrystals (CNCs) were incorporated into electrospun fibers to enhance mechanical properties. The gelatin coating was applied to the lumen using perfusion coating, resembling the inner layer. Integration of 3D-printed structures with electrospun fibers via template-assisted electrospinning and gelatin coating resulted in a seamless multilayered scaffold. Mechanical testing demonstrated robustness, surpassing natural arteries in some aspects, while the gelatin coating significantly reduced liquid leakage, ensuring leak-free functionality. Cytotoxicity assessment confirmed the biocompatibility of processed materials with fibroblast cells, supporting potential for medical applications.

Culprit Lesion Vessel Size and Risk of Reperfusion Injury in ST-Segment Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study

BACKGROUND

Microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH) are well-established imaging biomarkers of failed myocardial tissue reperfusion in patients with ST-segment elevation-myocardial infarction treated with percutaneous coronary intervention. MVO and IMH are associated with an increased risk of adverse outcome independent of infarct size, but whether the size of the culprit lesion vessel plays a role in the occurrence and severity of reperfusion injury is currently unknown. This study aimed to evaluate the association between culprit lesion vessel size and the occurrence and severity of reperfusion injury as determined by cardiac magnetic resonance imaging.

METHODS AND RESULTS

Patients (n=516) with first-time ST-segment-elevation myocardial infarction underwent evaluation with cardiac magnetic resonance at 4 (3-5) days after infarction. MVO was assessed with late gadolinium enhancement imaging and IMH with T2* mapping. Vessel dimensions were determined using catheter-based reference. Median culprit lesion vessel size was 3.1 (2.7-3.6) mm. MVO and IMH were found in 299 (58%) and 182 (35%) patients. Culprit lesion vessel size was associated with body surface area, diabetes, total ischemic time, postinterventional thrombolysis in myocardial infarction flow, and infarct size. There was no association between vessel size and MVO or IMH in univariable and multivariable analysis (P>0.05). These findings were consistent across patient subgroups with left anterior descending artery and non-left anterior descending artery infarctions and those with thrombolysis in myocardial infarction 3 flow post-percutaneous coronary intervention.

CONCLUSIONS

Comprehensive characterization of myocardial tissue reperfusion injury by cardiac magnetic resonance revealed no association between culprit lesion vessel size and the occurrence of MVO and IMH in patients treated with primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction.

Drug-coated balloon: an effective alternative to stent strategy in small-vessel coronary artery disease-a meta-analysis

Background

Small-vessel coronary artery disease (CAD) is frequently observed in coronary angiography and linked to a higher risk of lesion failure and restenosis. Currently, treatment of small vessels is not standardized while having drug-eluting stents (DES) or drug-coated balloons (DCBs) as possible strategies. We aimed to conduct a meta-analytic approach to assess the effectiveness of treatment strategies and outcomes for small-vessel CAD.

Methods

Comprehensive literature search was conducted using PubMed, Embase, MEDLINE, and Cochrane Library databases to identify studies reporting treatment strategies of small-vessel CAD with a reference diameter of ≤3.0 mm. Target lesion revascularization (TLR), target lesion thrombosis, all-cause death, myocardial infarction (MI), and major adverse cardiac events (MACE) were defined as clinical outcomes. Outcomes from single-arm and randomized studies based on measures by means of their corresponding 95% confidence intervals (CI) were compared using a meta-analytic approach. Statistical significance was assumed if CIs did not overlap.

Results

Thirty-seven eligible studies with a total of 31,835 patients with small-vessel CAD were included in the present analysis. Among those, 28,147 patients were treated with DES (24 studies) and 3,299 patients with DCB (18 studies). Common baseline characteristics were equally distributed in the different studies. TLR rate was 4% in both treatment strategies [0.04; 95% CI 0.03-0.05 (DES) vs. 0.03-0.07 (DCB)]. MI occurred in 3% of patients receiving DES and in 2% treated with DCB [0.03 (0.02-0.04) vs. 0.02 (0.01-0.03)]. All-cause mortality was 3% in the DES group [0.03 (0.02-0.05)] compared with 1% in the DCB group [0.01 (0.00-0.03)]. Approximately 9% of patients with DES developed MACE vs. 4% of patients with DCB [0.09 (0.07-0.10) vs. 0.04 (0.02-0.08)]. Meta-regression analysis did not show a significant impact of reference vessel diameter on outcomes.

Conclusion

This large meta-analytic approach demonstrates similar clinical and angiographic results between treatment strategies with DES and DCB in small-vessel CAD. Therefore, DES may be waived in small coronary arteries when PCI is performed with DCB.