Coronary tortuosity is negatively correlated with coronary atherosclerosis

A fully automated deep learning approach for coronary artery segmentation and comprehensive characterization

Coronary computed tomography angiography (CCTA) allows detailed assessment of early markers associated with coronary artery disease (CAD), such as coronary artery calcium (CAC) and tortuosity (CorT). However, their analysis can be time-demanding and biased. We present a fully automated pipeline that performs (i) coronary artery segmentation and (ii) CAC and CorT objective analysis. Our method exploits supervised learning for the segmentation of the lumen, and then, CAC and CorT are automatically quantified. 281 manually annotated CCTA images were used to train a two-stage U-Net-based architecture. The first stage employed a 2.5D U-Net trained on axial, coronal, and sagittal slices for preliminary segmentation, while the second stage utilized a multichannel 3D U-Net for refinement. Then, a geometric post-processing was implemented: vessel centerlines were extracted, and tortuosity score was quantified as the count of branches with three or more bends with change in direction forming an angle >45°. CAC scoring relied on image attenuation. CAC was detected by setting a patient specific threshold, then a region growing algorithm was applied for refinement. The application of the complete pipeline required <5 min per patient. The model trained for coronary segmentation yielded a Dice score of 0.896 and a mean surface distance of 1.027 mm compared to the reference ground truth. Tracts that presented stenosis were correctly segmented. The vessel tortuosity significantly increased locally, moving from proximal, to distal regions (p < 0.001). Calcium volume score exhibited an opposite trend (p < 0.001), with larger plaques in the proximal regions. Volume score was lower in patients with a higher tortuosity score (p < 0.001). Our results suggest a linked negative correlation between tortuosity and calcific plaque formation. We implemented a fast and objective tool, suitable for population studies, that can help clinician in the quantification of CAC and various coronary morphological parameters, which is helpful for CAD risk assessment.

Coronary Tortuosity Index vs. Angle Measurement Method for the Quantification of the Tortuosity of Coronary Arteries in Non-Obstructive Coronary Disease

Coronary tortuosity has been recognized as a potential pathophysiological mechanism in the development of non-obstructive coronary artery disease (CAD). The aim of this study was to examine the role of two coronary tortuosity measurement methods in the detection of clinically significant coronary tortuosity. The study included 160 patients with angina symptoms and myocardial ischemia detected by cardiac stress tests in chronic settings and those diagnosed with acute coronary syndrome. After coronary angiography, tortuosity of coronary arteries was assessed by two methods, including measurement of tortuosity angles and calculating of tortuosity index. Significantly more tortuous coronary arteries were detected in the group with non-obstructive CAD (p < 0.01 for all three arteries), with significantly higher tortuosity index (TI) for all three coronary arteries in this group of patients, compared to patients with obstructive CAD. The highest TI for LCX was found in patients with lateral ischemia (p < 0.001) and for LAD in patients with anterior ischemia (p < 0.001). When measured by the angle method, the only association was found between LCX tortuosity and lateral ischemia (OR 4.9, p = 0.046). In conclusion, coronary tortuosity represents a pathophysiological mechanism for myocardial ischemia in non-obstructive CAD. The coronary tortuosity index could be a reliable and widely applicable tool for the quantification of coronary tortuosity.

The Association of Severe Coronary Tortuosity and Non-Obstructive Coronary Artery Disease

Background and Objectives: There is an increasing interest in the coronary tortuosity as a novel pathophysiological mechanism of ischemia in coronary artery disease without significant obstruction, but there are a lack of studies to confirm this relationship in the clinical setting. The aim of our study was to evaluate the association of severe coronary tortuosity and the potential role of coronary blood supply dominance in the appearance of myocardial ischemia in patients with non-obstructive coronary artery disease (non-CAD), compared to patients with obstructive coronary artery disease (CAD). Materials and Methods: The study enrolled 131 participants (71 male and 60 female), recruited among patients referred to cardiologists due to angina symptoms with ischemic alterations established by cardiac stress tests, as well as those admitted to the hospital for acute coronary syndrome. Results: Mean age of recruited patients was 61.6 (±10.1) years. According to the coronary angiography, they were divided into two groups: non-obstructive and obstructive CAD (77 and 54, respectively). There were significantly more women (61% vs. 24%, p < 0.001) in the non-CAD group. Both tortuous coronary arteries (50.6% vs. 14.8%, p < 0.001) and left coronary dominance (37.7% vs. 16.7%, p = 0.006) were more frequent in the non-CAD group compared to the CAD group. Female sex (OR = 17.516, p = 0.001), tortuous coronary arteries (OR = 7.962, p = 0.006) and left dominance of blood supply were significant predictors for non-CAD. Conclusions: Non-obstructive CAD is common among patients, especially women, who are referred for coronary angiography. Severe coronary artery tortuosity is the strongest independent predictor of non-obstructive CAD, followed by female gender and left coronary dominance.

Pathological Roles of Oxidative Stress in Cardiac Microvascular Injury

Cardiac microvascular injury can be a fundamental pathological process that causes high incidence cardiovascular diseases such heart failure, diabetic cardiomyopathy, and hypertension. It is also an independent risk factor for cardiovascular disease. Oxidative stress is a significant pathological process in which the body interferes with the balance of the endogenous antioxidant defense system by producing reactive oxygen species, leading to property changes and dysfunction. It has been demonstrated that oxidative stress is one of the major causes of cardiac microvascular disease. Therefore, additional investigation into the relationship between oxidative stress and cardiac microvascular injury will direct clinical management in the future. In order to give suggestions and support for future in-depth studies, we give a basic overview of the cardiac microvasculature in relation to physiopathology in this review. We also summarize the role of oxidative stress of mitochondrial and non-mitochondrial origin in cardiac microvascular injury and related drug studies.

Correlation of osteoprotegerin, sRANKL, inflammatory factors and epicardial adipose tissue volume with coronary heart disease

BACKGROUND

To observe the correlation of osteoprotegerin, soluble receptor activator of nuclear factor-κB ligand (sRANKL), inflammatory factors and epicardial adipose tissue volume (EATV) with the severity of coronary heart disease (CHD).

METHODS

We studied 390 patients who were admitted to the Department of Cardiology of our hospital because of chest pain and underwent coronary angiography (CAG) from August 2018 to December 2019. According to CAG, 209 patients had non-CHD and 181 patients had CHD. Demographic data, biochemical indicators including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), lipoprotein a (Lp(a)), apolipoprotein B (apoB), apolipoprotein AI (apoAI), creatine kinase isoenzyme (CK-MB), osteoprotegerin, sRANKL, inflammatory factors (hs-CRP, FIB and IL-6), and EATV were collected.

RESULTS

The number of males, age, diabetes and hypertension in the CHD group was higher than those in the non-CHD group (P < .05). LDL-C, TC and apoB in the two groups were not significantly different (P > .05); HDL-C and apoAI in the CHD group were lower than those in the non-CHD group, and Lp(a) and CK-MB were higher than those in the control group (P < .05). Osteoprotegerin, IL-6, hs-CRP, EATV and FIB in the CHD group were higher than those in the non-CHD group, while sRANKL was lower than that in the control group (P < .05). Pearson correlation analysis showed that osteoprotegerin, sRANKL, inflammatory factors (hs-CRP, FIB and IL-6) and EATV were correlated with the severity of CHD (P < .05). Multivariate logistic regression analysis showed that CK-MB, osteoprotegerin, sRANKL, inflammatory factors (hs-CRP, FIB and IL-6) and EATV were risk factors for CHD, while HDL-C, Lp(a), apoAI were protective factors.

CONCLUSION

Osteoprotegerin, sRANKL, inflammatory factors and EATV were positively correlated with the severity of CHD, which had certain value for the diagnosis of CHD.

Coronary arterial geometry: A comprehensive comparison of two imaging modalities

The characterization of vascular geometry is a fundamental step towards the correct interpretation of coronary artery disease. In this work, we report a comprehensive comparison of the geometry featured by coronary vessels as obtained from coronary computed tomography angiography (CCTA) and the combination of intravascular ultrasound (IVUS) with bi-plane angiography (AX) modalities. We analyzed 34 vessels from 28 patients with coronary disease, which were deferred to CCTA and IVUS procedures. We discuss agreement and discrepancies between several geometric indexes extracted from vascular geometries. Such an analysis allows us to understand to which extent the coronary vascular geometry can be reliable in the interpretation of geometric risk factors, and as a surrogate to characterize coronary artery disease.

Is coronary artery tortuosity a predisposing factor for drug-eluting stent restenosis?

BACKGROUND

Coronary artery tortuosity (CAT) is a relatively common finding on coronary angiography and may be associated with impaired left ventricular relaxation and coronary ischemia However, the significance of CAT remains unknown. This study aimed to investigate whether the severity of tortuosity in the targeted coronary segment is a predictor of stent restenosis.

METHODS

The study included a total of 637 patients undergoing drug-eluting stent implantation due to stable or unstable angina and who had no native coronary artery stenosis on their last coronary angiogram. The patients were separated into two groups: 312 patients with in-stent restenosis and 325 patients without in-stent restenosis. All patients underwent computed tomography (CT) coronary angiography after invasive angiography and CAT was calculated using the computer software.

RESULTS

Patients with in-stent restenosis had higher CAT than those without restenosis (1.25 ± 0.11 vs. 1.11 + 0.07, p < 0.001). Multivariate Cox regression analysis showed that the tortuosity index (hazard ratio [HR]: 1.246 95% confidence interval [CI]: 1.127-1.376 p < 0.001) and the circumflex lesion (HR: 1.437 95% CI: 1.062-1.942 p = 0.019) were independently associated with in-stent restenosis. With the threshold value of severe tortuosity set at 1.15, the prediction of could be made with 81% sensitivity and 80% specificity.

CONCLUSION

The severity of tortuosity is proportional to coronary in-stent stenosis in patients with stable and unstable angina pectoris undergoing drug-eluting stent implantation for a severe single coronary artery.

M1 macrophages-derived extracellular vesicles elevate microRNA-185-3p to aggravate the development of atherosclerosis in ApoE-/- mice by inhibiting small mothers against decapentaplegic 7

OBJECTIVE

Extracellular vesicles (EVs) are vital mediators of transferring microRNAs (miRNAs). We focused on effect of miR-185-3p that mediated by macrophages-derived EVs on atherosclerosis (AS) by targeting small mothers against decapentaplegic 7 (Smad7).

METHODS

EVs were extracted from M1 macrophages and identified. ApoE-/- mice were treated with EVs, EVs containing miR-185-3p inhibitor or mimic, then the pathological changes of mouse aorta were observed. The levels of blood lipid, cell adhesion molecules, oxidative stress factors, inflammatory factors, and proliferation and apoptosis of vascular endothelial cells were assessed. Expression of miR-185-3p and Smad7 was detected and the targeting relationship between miR-185-3p and Smad7 was validated.

RESULTS

MiR-185-3p was upregulated while Smad7 was downregulated in atherosclerotic mouse aorta. M1 macrophages-derived EVs elevated miR-185-3p to promote development of AS pathology and levels of blood lipid, endothelial cellular adhesion, oxidative stress factors and inflammatory factors, suppressed cell proliferation and promoted cell apoptosis of vascular endothelial cells in atherosclerotic mice through downregulating Smad7. Smad7 was a target gene of miR-185-3p and miR-185-3p could inhibit expression of Smad7.

CONCLUSION

M1 macrophages-derived EVs and upregulated miR-185-3p aggravated the development of AS in ApoE-/- mice by negatively regulating Smad7. This research may further the understanding of AS mechanism.

Coronary flow reserve and microcirculatory resistance in patients with coronary tortuosity and without atherosclerosis

Objective

Coronary tortuosity may affect epicardial coronary arterial blood flow. This study aimed to investigate the effect of coronary tortuosity on coronary flow reserve and the coronary microcirculation in patients without apparent coronary atherosclerosis.

Methods

Prospective patients (n = 8, 3 men, mean age: 58 ± 6.0 years) with coronary tortuosity and without apparent coronary atherosclerosis were enrolled. Coronary tortuosity was defined by the finding of ≥three bends (defined as a ≥45° change in vessel direction) along the main trunk of the left anterior descending artery or left circumflex artery. Coronary flow reserve and the index of microcirculatory resistance were measured by the thermodilution technique.

Results

A total of eight coronary arteries with coronary tortuosity were analyzed. The mean fractional flow reserve was 0.98 ± 0.007. The mean coronary flow reserve was 1.5 ± 0.3, which is much lower than that in the normal coronary artery as reported in the literature. The mean index of microcirculatory resistance was 26.7 ± 2.3, which is much higher than that in the normal coronary artery.

Conclusions

Coronary tortuosity is associated with decreased coronary flow reserve and an increased index of microcirculatory resistance.

Trial registration: This study is registered at the Chinese Clinical Trial Registry, NCT No: ChiCTR2000033671