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Coronary-artery dissections account for less than 1% of acute myocardial infarctions, occur most commonly in women and most often between the ages of 47 and 53 years, may be associated with an underlying disorder such as fibromuscular dysplasia and other noncoronary arterial abnormalities, and are usually treated medically.

Severe coronary tortuosity has previously been linked to low shear stresses at the luminal surface, yet this relationship is not fully understood. Several previous studies considered different tortuosity metrics when exploring its impact of on the wall shear stress (WSS), which has likely contributed to the ambiguous findings in the literature. Here, we aim to analyze different tortuosity metrics to determine a benchmark for the highest correlating metric with low time-averaged WSS (TAWSS). Using Computed Tomography Coronary Angiogram (CTCA) data from 127 patients without coronary artery disease, we applied all previously used tortuosity metrics to the left main coronary artery bifurcation, and to its left anterior descending and left circumflex branches, before modelling their TAWSS using computational fluid dynamics (CFD). The tortuosity measures included tortuosity index, average absolute-curvature, root-mean-squared (RMS) curvature, and average squared-derivative-curvature. Each tortuosity measure was then correlated with the percentage of vessel area that showed a < 0.4 Pa TAWSS, a threshold associated with altered endothelial cell cytoarchitecture and potentially higher disease risk. Our results showed a stronger correlation between curvature-based versus non-curvature-based tortuosity measures and low TAWSS, with the average-absolute-curvature showing the highest coefficient of determination across all left main branches ( p  < 0.001), followed by the average-squared-derivative-curvature ( p  = 0.001), and RMS-curvature ( p  = 0.002). The tortuosity index, the most widely used measure in literature, showed no significant correlation to low TAWSS ( p  = 0.86). We thus recommend the use of average-absolute-curvature as a tortuosity measure for future studies.

Introduction Fractional flow reserve (FFR) measured after percutaneous coronary intervention (PCI) has been identified as a surrogate marker for vessel related adverse events. FFR can be derived from standard coronary computed tomography angiography (CTA). Moreover, the FFR derived from coronary CTA (FFRCT) Planner is a tool that simulates PCI providing modeled FFRCT values after stenosis opening. Aim To validate the accuracy of the FFRCT Planner in predicting FFR after PCI with invasive FFR as a reference standard. Methods Prospective, international and multicenter study of patients with chronic coronary syndromes undergoing PCI. Patients will undergo coronary CTA with FFRCT prior to PCI. Combined morphological and functional evaluations with motorized FFR hyperemic pullbacks, and optical coherence tomography (OCT) will be performed before and after PCI. The FFRCT Planner will be applied by an independent core laboratory blinded to invasive data, replicating the invasive procedure. The primary objective is to assess the agreement between the predicted FFRCT post‐PCI derived from the Planner and invasive FFR. A total of 127 patients will be included in the study. Results Patient enrollment started in February 2019. Until December 2020, 100 patients have been included. Mean age was 64.1 ± 9.03, 76% were males and 24% diabetics. The target vessels for PCI were LAD 83%, LCX 6%, and RCA 11%. The final results are expected in 2021. Conclusion This study will determine the accuracy and precision of the FFRCT Planner to predict post‐PCI FFR in patients with chronic coronary syndromes undergoing percutaneous revascularization.

X-ray coronary angiography is a primary imaging technique for diagnosing coronary diseases. Although quantitative coronary angiography (QCA) provides morphological information of coronary arteries with objective quantitative measures, considerable training is required to identify the target vessels and understand the tree structure of coronary arteries. Despite the use of computer-aided tools, such as the edge-detection method, manual correction is necessary for accurate segmentation of coronary vessels. In the present study, we proposed a robust method for major vessel segmentation using deep learning models with fully convolutional networks. When angiographic images of 3302 diseased major vessels from 2042 patients were tested, deep learning networks accurately identified and segmented the major vessels in X-ray coronary angiography. The average F1 score reached 0.917, and 93.7% of the images exhibited a high F1 score > 0.8. The most narrowed region at the stenosis was distinctly captured with high connectivity. Robust predictability was validated for the external dataset with different image characteristics. For major vessel segmentation, our approach demonstrated that prediction could be completed in real time with minimal image preprocessing. By applying deep learning segmentation, QCA analysis could be further automated, thereby facilitating the use of QCA-based diagnostic methods.

BackgroundPathological mechanisms of myocardial infarction with non-obstructive coronary arteries (MINOCA) are heterogeneous, with an unknown impact on prognosis, and often remain unrecognised in clinical practice. This study aimed to evaluate the prevalence and prognostic impact of pathological findings by invasive coronary angiography (ICA), optical coherence tomography (OCT), and coronary function testing in MINOCA.MethodsStudies published until August 2023 were searched on PubMed and SCOPUS and included if reporting the prevalence of patients with non-obstructive coronary arteries (NObs-CA; 1–49% coronary stenosis) versus normal coronary arteries (NCA; 0% coronary stenosis) by ICA, pathological findings by OCT, and/or coronary vasomotor tests in MINOCA. Newcastle-Ottawa Scale was used for quality assessment. The pooled prevalence of pathological findings was estimated with random-effects models. Pooled risk ratios (RRs) with 95% CIs of all-cause death, MI and the composite of both in patients with NObs-CA versus NCA were calculated at short-term (<1 month), 1-year and long-term follow-up (> 1 year).ResultsForty-five studies including 17 539 patients were analysed. The pooled prevalence of NObs-CA at ICA was 53% (95% CI 0.47 to 0.60). OCT showed acute pathological findings in 62% (95% CI 0.44 to 0.78) of patients and coronary vasomotor tests were positive in 49% (95% CI 0.31 to 0.67). NObs-CA compared with NCA was associated with an increased 1-year risk of all-cause death or MI (RR=1.49 (95% CI 1.17 to 1.90)) and MI alone (RR=1.80 (95% CI 1.26 to 2.59)), whereas the risk of all-cause death was comparable. Similar results were seen at long-term, but not at short-term follow-up.ConclusionsStratification of MINOCA into NObs-CA versus NCA has prognostic value. OCT and vasospasm testing, often informative about the pathological mechanism of MINOCA, should be part of an invasive diagnostic algorithm.PROSPERO registration numberCRD42023468183

In a registry-based trial, FFR-guided PCI of nonculprit lesions did not result in a lower risk of a composite of death from any cause, myocardial infarction, or unplanned revascularization than culprit-lesion-only PCI.

Spontaneous coronary artery dissection (SCAD) has emerged over the last decade as an increasingly recognised cause of myocardial infarction, especially among younger women. The advances in our understanding of SCAD and the evolution of coronary angiography and intracoronary imaging have led to improved diagnoses and outcomes; however, there are still knowledge gaps and challenges in the management of this condition. In this review, we summarise the pathogenesis, genetics, diagnosis and acute and chronic management of patients with SCAD. We also provide focused updates on the following: genetics of SCAD, the role of cardiac CT angiography and cardiac MRI, the use of intracoronary imaging, revascularisation techniques and the overlap between SCAD and Takotsubo syndrome.

Implantation of drug-eluting stents (DES) is the dominant treatment strategy for patients with symptomatic coronary artery disease. However, the first-generation DES had substantial drawbacks, including delayed healing, local hypersensitivity reactions and neoatherosclerosis, which all led to a steady increase in major adverse cardiovascular events over time. Subsequently, newer-generation DES were introduced with thinner struts, different scaffold designs (to improve deliverability while maintaining radial strength), different durable and biodegradable polymers — and in some cases no polymer (to improve vascular biocompatibility) — and new antiproliferative drug types and doses. Currently, >30 different DES are commercially available in Europe, with fewer available in the USA but with many new entrants coming onto the US market in the next few years. Never before have cardiologists been faced with so many choices of stent, each with its own unique design. In this Review, we detail preclinical and pathology studies for each stent design, examining thromboresistance, speed of neointimal coverage and completeness of healing, including endothelialization. We conclude by discussing how these design characteristics might affect the potential for shortening the minimum duration of dual antiplatelet therapy needed after coronary intervention.

ObjectiveTo investigate percutaneous coronary intervention (PCI) practice in an international cohort of patients with spontaneous coronary artery dissection (SCAD). To explore factors associated with complications and study angiographic and longer term outcomes.MethodsSCAD patients (n=215, 94% female) who underwent PCI from three national cohort studies were investigated and compared with a matched cohort of conservatively managed SCAD patients (n=221).ResultsSCAD-PCI patients were high risk at presentation with only 8.8% undergoing PCI outside the context of ST-elevation myocardial infarction/cardiac arrest, thrombolysis in myocardial infarction (TIMI) 0/1 flow or proximal dissections. PCI complications occurred in 38.6% (83/215), with 13.0% (28/215) serious complications. PCI-related complications were associated with more extensive dissections (multiple vs single American Heart Association coronary segments, OR 1.9 (95% CI: 1.06–3.39),p=0.030), more proximal dissections (proximal diameter per mm, OR 2.25 (1.38–3.67), p=0.001) and dissections with no contrast penetration of the false lumen (Yip-Saw 2 versus 1, OR 2.89 (1.12–7.43), p=0.028). SCAD-PCI involved long lengths of stent (median 46mm, IQR: 29–61mm). Despite these risks, SCAD-PCI led to angiographic improvements in those with reduced TIMI flow in 84.3% (118/140). Worsening TIMI flow was only seen in 7.0% (15/215) of SCAD-PCI patients. Post-PCI major adverse cardiovascular and cerebrovascular events (MACCE) and left ventricular function outcomes were favourable.ConclusionWhile a conservative approach to revascularisation is favoured, SCAD cases with higher risk presentations may require PCI. SCAD-PCI is associated with longer stent lengths and a higher risk of complications but leads to overall improvements in coronary flow and good medium-term outcomes in patients.