Treatment of de novo coronary artery bifurcation lesions with drug coated balloons: A reappraisal according to the available scientific data

Role of secondary flows in coronary artery bifurcations before and after stenting: What is known so far?

Coronary arteries are uniformly exposed to traditional cardiovascular risk factors. However, atherosclerotic lesions occur in preferential regions of the coronary tree, especially in areas with disturbed local blood flow, such as coronary bifurcations. Over the latest years, secondary flows have been linked to the inception and progression of atherosclerosis. Most of these novel findings have been obtained in the field of computational fluid dynamic (CFD) analysis and biomechanics but remain poorly understood by cardiovascular interventionalists, despite the important impact that they may have in clinical practice. We aimed to summarize the current available data regarding the pathophysiological role of secondary flows in coronary artery bifurcation, providing an interpretation of these findings from an interventional perspective.

Establishment of a Nomogram for Predicting the Suboptimal Angiographic Outcomes of Coronary De Novo Lesions Treated with Drug-Coated Balloons

INTRODUCTION

Factors affecting the angiographic outcomes of coronary de novo lesions treated with drug-coated balloons (DCBs) have not been well illustrated. The aim of the study is to establish a nomogram for predicting the risk of suboptimal diameter stenosis (DS) at angiographic follow-up.

METHODS

A retrospective analysis was performed on a cohort of patients who underwent DCB intervention for coronary de novo lesions with angiographic follow-up data. Multivariable logistic regression analysis was applied to determine the independent predictors of DS ≥ 30% at follow-up, and then a nomogram model was established and validated.

RESULTS

A total of 196 patients (313 lesions) were divided into the suboptimal (DS ≥ 30%) and optimal (DS < 30%) DS groups according to quantitative coronary angiography (QCA) measurements of the target lesions at follow-up. Seven independent factors including calcified lesions, true bifurcation lesions, immediate lumen gain rate (iLG%) < 20%, immediate diameter stenosis (iDS) ≥ 30%, DCB diameter/reference vessel diameter ratio (DCB/RVD) < 1.0, DCB length and mild dissection were identified. The area under the curve (AUC) (95% CI) of the receiver-operating characteristic (ROC) curve of the nomogram was 0.738 (0.683, 0.794). After the internal validation, the AUC (95% CI) was 0.740 (0.685, 0.795). The Hosmer-Lemeshow goodness of fit (GOF) test (χ² = 6.57, P = 0.766) and the calibration curve suggested a good predictive consistency of the nomogram.

CONCLUSIONS

The well-calibrated nomogram could efficiently predict the suboptimal angiographic outcomes at follow-up. This model may be helpful to optimize lesion preparation to achieve optimal outcomes.

Impact of late lumen loss on clinical outcomes of side branch bifurcation lesions treated by drug-coated balloon angioplasty with main branch stenting

BACKGROUND

Drug-coated balloon (DCB) angioplasty for side branches with main branch stenting is effective for bifurcation lesions and reduces late lumen loss (LLL) in side branches. However, the predictors and clinical implications of LLL after DCB angioplasty are largely unexplored.

METHODS

Among 181 patients undergoing DCB angioplasty for side branches with drug-eluting stent implantation for main branches between 2016 and 2018, we enrolled 138 patients (138 lesions) undergoing follow-up coronary angiography within 1 year. The 1-year cumulative rates of target lesion revascularization (TLR) and major adverse cardiac events (MACE: defined as a composite of all-cause death, myocardial infarction, and TLR) were compared between patients with late lumen gain (LLG) (LLG group) and those with LLL (LLL group).

RESULTS

The binary restenosis rate of the side branch was 8.0% (11 lesions), mean LLL was -0.14 ± 0.43 mm, and LLG was observed in 99 lesions (71.7%). The DCB size/reference vessel diameter ratio showed mild discrimination (area under the curve, 0.60; 95% confidence interval, 1.2-65.0; p = 0.03) for predicting the side branch progression. The 1-year cumulative rates of MACE and TLR were not significantly different but numerically lower in the LLG group than in the LLL group (2.0% vs. 7.8%, p = 0.11 and 2.0% vs. 7.7%, p = 0.11, respectively). Lumen regression after DCB angioplasty for side branches are associated with improved clinical outcomes.

CONCLUSIONS

The DCB size relative to the reference vessel diameter is a predictor of late lumen enlargement in side branches.

Drug-coated balloons: Technical and clinical progress

The advancement of drug-coated balloons (DCB) presents an alternative nonstent method in the percutaneous treatment of atherosclerotic lesions. While the current generation of drug-eluting stents (DES) are the device of choice, especially in coronary artery disease (CAD), DCB has potential applications in the treatment of de novo lesions, in-stent restenosis (ISR), bifurcations, and in peripheral artery disease (PAD). In terms of coronary clinical experience, DCB is used most in ISR scenarios and more data are collected to support the use of DCB in de novo lesions compared to best-in-class DES. The use of DCB in bifurcation side branch treatment has demonstrated safety, and with good angiographic and clinical outcomes, but more data from randomized trials will be required to assess its clinical value. For PAD, the clinical outcomes of DCB with and without debulking devices in diseased femoropopliteal arteries and treatment of below-the-knee (BTK) vessels with DCB are discussed. Current data demonstrated conflicting long-term safety outcomes in the use of paclitaxel devices in the femoral and/or popliteal arteries, while the role of DCB in BTK disease remains uncertain due to a lack of randomized controlled trial data. In summary, this review provides an overall view of current DCB technologies and progress, followed by an update on DCB clinical data in the treatment of CAD and PAD.

A Novel Biodegradable Multilayered Bioengineered Vascular Construct with a Curved Structure and Multi-Branches

Constructing tissue engineered vascular grafts (TEVG) is of great significance for cardiovascular research. However, most of the fabrication techniques are unable to construct TEVG with a bifurcated and curved structure. This paper presents multilayered biodegradable TEVGs with a curved structure and multi-branches. The technique combined 3D printed molds and casting hydrogel and sacrificial material to create vessel-mimicking constructs with customizable structural parameters. Compared with other fabrication methods, the proposed technique can create more native-like 3D geometries. The diameter and wall thickness of the fabricated constructs can be independently controlled, providing a feasible approach for TEVG construction. Enzymatically-crosslinked gelatin was used as the material of the constructs. The mechanical properties and thermostability of the constructs were evaluated. Fluid-structure interaction simulations were conducted to examine the displacement of the construct’s wall when blood flows through it. Human umbilical vein endothelial cells (HUVECs) were seeded on the inner channel of the constructs and cultured for 72 h. The cell morphology was assessed. The results showed that the proposed technique had good application potentials, and will hopefully provide a novel technological approach for constructing integrated vasculature for tissue engineering.