Factors Influencing Stent Failure in Chronic Total Occlusion Coronary Intervention

Stent failure remains one of the greatest challenges for interventional cardiologists. Despite the evolution to superior second- and third-generation drug-eluting stent designs, increasing use of intracoronary imaging and the adoption of more potent antiplatelet regimens, registries continue to demonstrate a prevalence of stent failure or target lesion revascularisation of 15–20%. Predisposition to stent failure is consistent across both chronic total occlusion (CTO) and non-CTO populations and includes patient-, lesion- and procedure-related factors. However, histological and pathophysiological properties specific to CTOs, alongside complex strategies to treat these lesions, may potentially render percutaneous coronary interventions in this cohort more vulnerable to failure. Prevention requires recognition and mitigation of the precipitants of stent failure, optimisation of interventional techniques, including image-guided precision percutaneous coronary intervention, and aggressive modification of a patient’s cardiovascular risk factors. Management of stent failure in the CTO population is technically challenging and itself begets recurrence. We aim to provide a comprehensive review of factors influencing stent failure in the CTO population and strategies to attenuate these.

Bioabsorbable vascular scaffolds in routine practice: long-term results

Background Recent publications suggest that bioabsorbable vascular scaffolds (BVS) carry an excess of thrombotic complications. Our goal was to describe the results in real life and in the long term, in a series of patients who received a BVS which is currently off the market. Methods Two hundred and thirteen consecutive patients who received at least 1 BVS between May 2012 and December 2016 were analyzed. The primary objective was the incidence of the compound event “target vessel failure” that included infarction or target vessel revascularization and cardiac death. Results Seventy-five percent of patients were men with a mean age of 61.4 years. They had a high prevalence of dyslipidemia (62.44%) and smoking (65.26%). The most common cause of admission was myocardial infarction without ST elevation (53.52%). A total of 233 coronary lesions were treated, with an average of 1.3±0.3 lesions per patient. The implant was successful in 99.5% of cases. Predilatation was performed in 89.3% and post dilation in 33.5% of cases. The use of intracoronary imaging (Optical Coherence Tomography OCT and/or Intravascular ultrasonography IVUS) to optimize the BVS implant was performed in 86 patients (40.38%). With a mean follow-up of 42.5 months, the incidence of target vessel failure was 6.57% during the first 24 months and 7.98% at the end of the follow-up. Regarding the device, this included 6 cases (2.81%) of thrombosis (definitive, probable or possible) and 10 cases (4.69%) of restenosis. Patients with a history of diabetes mellitus (HR 1.72 95% CI 1.01–2.95 P=0,05) and/or chronic oral anticoagulation (HR 5.71 95% CI 1.12–28.94 P=0.04) had a higher risk of target vessel failure. The use of intracoronary imaging (OCT and/or IVUS) during the BVS implantation had a considerable trend toward significance as a protective factor (HR 0.32 95% CI 0.11–1.03 P=0.06). Conclusions In this series of patients; in real life conditions, the incidence of target vessel failure was comparable to that previously described in randomized clinical trials. The events were more frequent during the first 2 years of follow-up, in the presence of greater cardiovascular comorbidity and in the absence of intracoronary imaging during the implantation. FUNDunding Acknowledgement Type of funding sources: Other. Main funding source(s): European Society of Cardiology KM curve for target vessel failure (TVF) Predictor analysis for TVF

Moving shear stress towards the clinic: preclinical comparison of optical coherence tomography-based versus angiography-based time-averaged wall shear stress estimations

Introduction Identification of coronary atherosclerotic plaques at risk of causing future acute coronary syndromes remains a major unmet clinical challenge. The addition of vessel biomechanics to intracoronary imaging derived evaluation of plaque morphology, improves identification of plaques likely to develop high risk features. We and others have developed a framework for intracoronary imaging (optical coherence tomography [OCT]) based 3D reconstructions of coronary arteries for computational fluid dynamics (CFD) simulations of shear stress, which are considered the current gold standard approach for quantification of coronary arterial haemodynamics. However, these approaches are time consuming and computationally intensive, resulting in a barrier to clinical uptake. Purpose Determination of time averaged wall shear stress (TAWSS) based on 3D coronary geometries from non-invasive 3D Quantitative Coronary Angiography (3D-QCA) has recently been developed (Pie Medical Imaging, Netherlands), which enables results of shear stress simulations to be available within 30 minutes. We sought to compare TAWSS determined from 3D-QCA with gold standard OCT-based CFD simulations in both normal and stenotic arteries in minipigs. Methods 15 normal and 5 stenotic minipig coronary arteries were studied. Anatomically matched 3D arterial geometries were reconstructed from 3D-QCA and OCT using common centrelines. Boundary conditions for simulations included directly measured inlet blood velocities; parabolic inlet flow profiles, zero pressure outlet; no-slip arterial walls; blood density: 1.05 g/ml; blood dynamic viscosity: 0.035 g/cm.s. Blood was modelled as Newtonian. 3D-QCA TAWSS was obtained with a Kratos Multi-Physics CFD solver. OCT-based simulations were performed using Abaqus/CFD v6.14. TAWSS was calculated for 80 axially matched segments for both methods (1200 and 400 paired comparisons for normal and stenotic arteries, respectively). Data were analysed using Bland-Altman and Wilcoxon matched-pairs signed ranked tests. Results Computation times for 3D-QCA and OCT-based CFD were approximately 30 minutes and 2 hours respectively. Axial profiles of TAWSS were similar between the two methods and there was agreement in TAWSS magnitudes and narrow 95% limits of agreement (Figure 1 and Figure 2). Using co-registered TAWSS maps generated by each method, we find similar spatial regional distributions of TAWSS in both normal and stenotic arteries. Conclusions Our data suggest that 3D-QCA based TAWSS is feasible in both normal and stenotic arteries. Spatial TAWSS distributions between the two methods are similar with agreement in matched TAWSS comparisons, though there are some small systematic differences in the absolute values of TAWSS, due to different resultant arterial geometries. These encouraging data suggest that further clinical evaluation of rapid TAWSS from 3D-QCA is warranted, which may facilitate clinical adoption of TAWSS assessment. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Medical Research Council

The invasive intracoronary imaging assessment of left main coronary artery disease

Left main coronary artery disease is associated with an unfavorable prognosis. Evidence-based decision making regarding the optimal revascularization strategy in patients with left main disease has become a challenge, in view of the recently published data. An improvement in outcomes following left main percutaneous interventions could be achieved by reducing the rate of repeat target lesion revascularization through stent optimization techniques. In the setting of left main disease, procedural guidance by intravascular ultrasound or optical coherence tomography is essential for good long-term results, in such a way that intravascular imaging has gained more of a therapeutic connotation. Besides stent optimization, intracoronary imaging quantifies lesion severity, guides lesion preparation through morphological data, facilitates stent selection through accurate vessel sizing, identifies the landing zones, diagnoses acute vessel wall complications such as stent-related edge dissection or intramural hematoma, and defines procedural success.This review focuses on the two main intracoronary imaging techniques used for diagnostic evaluation and procedural guidance in left main coronary artery disease: intravascular ultrasound and optical coherence tomography. Based on the most recently published data, the review discusses each technique’s advantages and pitfalls, and summarizes their indications.

Three Technologies That Will Guide Revascularization of Chronic Coronary Syndrome Patients into the 21st Century: A Review

Although medical therapy is the preferred first-line treatment for patients with chronic coronary syndrome (CCS), revascularization remains an important consideration. We present a review that identifies the three diagnostic technologies most important to guiding the decision to revascularize patients with CCS: (1) cardiac computed tomography, (2) intracoronary imaging, and (3) lesion-specific physiological guidance.