Coronary artery tortuosity: a narrative review

Evaluation of the Superficial Collecting Lymph Vessels' Vasa Vasorum in Lymphoedematous Limbs Using Video Capillaroscopy

OBJECTIVE

The pre-collecting and collecting lymph vessels have smooth muscle cells, and sufficient perfusion is vital to maintain their function. Although the vasa vasorum of the collecting lymph vessels (VVCL) have been histologically investigated, little is known about their physiology. This study aimed to investigate the relationship between morphology and blood flow of the VVCL in lymphoedematous limbs.

METHODS

Medical records of lower extremity lymphoedema patients who underwent video capillaroscopy observation during supermicrosurgical lymphaticovenous anastomosis (LVA) surgery were reviewed. The collecting lymph vessels, dissected for LVA, were examined under video capillaroscopy (GOKO Bscan-ZD, GOKO Imaging Devices Co., Japan) with a magnification of 175x and 620x. Blood flow velocity of the VVCL was calculated by measuring the red blood cell movement using software (GOKO-VIP ver. 1.0.0.4, GOKO Imaging Devices Co., Japan). Based on the video capillaroscopy findings, the VVCL were grouped according to their morphology; the VVCL morphology types and blood flow velocity were then compared according to the lymphosclerosis severity grade.

RESULTS

Sixty-seven lymph vessels in 20 lower extremity lymphoedema patients were evaluated, including s0 in 19 (28.4%), s1 in 34 (50.7%), s2 in 10 (14.9%), and s3 in four (6.0%) lymph vessels. The VVCLs were grouped into four types: type 1 (n = 4), type 2 (n = 37), type 3 (n = 19), and type 4 (n = 7). Blood flow velocity of the VVCL ranged 0 - 189.3 μm/sec (average 26.40 μm/sec). There were statistically significant differences in VVCL morphology (p < .001) and blood flow velocity (p < .001) according to lymphosclerotic severity.

CONCLUSION

Vasa vasorum of the collecting lymph vessels could be grouped into four types with different characteristics. Morphological and physiological changes of the VVCL were related to sclerotic changes of the collecting lymph vessels.

Coronary Artery Tortuosity Found in a Marathon Runner

Coronary artery tortuosity (CAT) is an anatomical anomaly in which the coronary arteries contain kinks or coils. It is usually found incidentally in elderly patients with long-standing uncontrolled hypertension. This case illustrates a 58-year-old female marathon runner who was found to have CAT, originally presenting with chest pain, hypotension, presyncope, and a severe cramping sensation in her legs.

Case report of severe coronary artery tortuosity with coexisting connective tissue disease

Coronary artery tortuosity (CAT) is frequently detected during coronary angiography or coronary electron-beam computed tomography angiography by cardiovascular interventionalists. In this article, we described the case of a 69-year-old female patient with recurrent chest discomfort for 1 month and recurrence 1 week ago, accompanied by emaciation, gastrointestinal discomfort, and low skin temperature at the extremities. After a series of tests, the patient was finally diagnosed with severe CAT and coexisting connective tissue disease. Accordingly, she was treated with conventional medications, and diet and lifestyle modifications. The symptoms of the patient resolved gradually after 1 year of follow-up. Although there is no unanimous conclusion on the pathogenesis and clinical characteristics of CAT, this disease may provide a clue to the diagnosis of connective tissue disease, and warrants exploration through further research.

Recurrent spontaneous coronary artery dissection

Spontaneous coronary artery dissection (SCAD) is a significant cause of myocardial infarction (MI) and is more prevalent in pregnancy. The disease is being increasingly appreciated and diagnosed with the development and application of coronary angiography and intravascular imaging. Recurrent spontaneous coronary artery dissection (R-SCAD) is relatively common, with recurrence rates ranging from 8 to 27%. R-SCAD usually involves anatomical sites different from the original SCAD lesion and can cause MI, ventricular arrhythmias, and cardiogenic shock. This study aims to conduct a comprehensive review of R-SCAD to identify early risk factors and guide prevention policies and interventions. In addition, the risk of R-SCAD in subsequent pregnancies in women with a history of SCAD is discussed.

Age prediction from coronary angiography using a deep neural network: Age as a potential label to extract prognosis-related imaging features

Coronary angiography (CAG) is still considered the reference standard for coronary artery assessment, especially in the treatment of acute coronary syndrome (ACS). Although aging causes changes in coronary arteries, the age-related imaging features on CAG and their prognostic relevance have not been fully characterized. We hypothesized that a deep neural network (DNN) model could be trained to estimate vascular age only using CAG and that this age prediction from CAG could show significant associations with clinical outcomes of ACS. A DNN was trained to estimate vascular age using ten separate frames from each of 5,923 CAG videos from 572 patients. It was then tested on 1,437 CAG videos from 144 patients. Subsequently, 298 ACS patients who underwent percutaneous coronary intervention (PCI) were analysed to assess whether predicted age by DNN was associated with clinical outcomes. Age predicted as a continuous variable showed mean absolute error of 4 years with R squared of 0.72 (r = 0.856). Among the ACS patients stratified by predicted age from CAG images before PCI, major adverse cardiovascular events (MACE) were more frequently observed in the older vascular age group than in the younger vascular age group (p = 0.017). Furthermore, after controlling for actual age, gender, peak creatine kinase, and history of heart failure, the older vascular age group independently suffered from more MACE (hazard ratio 2.14, 95% CI 1.07 to 4.29, p = 0.032). The vascular age estimated based on CAG imaging by DNN showed high predictive value. The age predicted from CAG images by DNN could have significant associations with clinical outcomes in patients with ACS.

Vitamin-D Deficiency and Supplementation Altered the Network of the Coronary Arteries in a Rodent Model—In Situ Video Microscopic Technique

The aim of our study was to identify whether vitamin-D deficiency (VDD) can alter the geometry of the coronary-resistance-artery system. Male Wistar rats were divided into vitamin-D-deficient (VD−, n = 10) and vitamin-D-supplemented (VD+, n = 8) groups. After eight weeks, branches and segments of the left-anterior-descending-coronary-artery (LAD) network were analyzed by a video-microscopy technique. Segments were divided into 50 μm-long cylindrical ring units. VDD did not increase the number of morphological abnormalities. The number of segments did not differ between the groups (VD−: 210 and VD+: 224; pooled data of 8 networks). A larger lumen area of branches was found in VD+ group, while 1–4-order branches were lengthier in the VD− group. VD− rats had less rich coronary-resistance-artery networks in terms of 50 µm-long units. (VD−: 6365 vs. VD+: 6602; pooled data of 8 networks). VD+ animals were richer in the 100–350 µm outer diameter range, and VD− animals were richer in the 400–550 µm-diameter units. In VD− rats, 150–200 and 300 µm units were almost missing at higher flow distances from the orifice. Serum vitamin-D alterations caused by dietary changes can affect the geometry of the coronary-artery network, which may contribute to vitamin-D-dependent changes in cardiovascular mortality.

Clinical implications of arterial hypertension in patients with spontaneous coronary artery dissection

BACKGROUND

Spontaneous coronary artery dissection (SCAD) is a rare but increasingly recognized cause of acute coronary syndrome. Many patients with SCAD have associated coronary risk factors. However, the implications of arterial hypertension in SCAD patients remain unknown.

OBJECTIVE

This study sought to assess the clinical implications of arterial hypertension in a nationwide cohort of patients with SCAD.

METHODS

The Spanish SCAD registry (NCT03607981) prospectively enrolled 318 consecutive patients. All coronary angiograms were centrally analyzed to confirm the diagnosis of SCAD. Patients were classified according to the presence of arterial hypertension.

RESULTS

One-hundred eighteen patients (37%) had a diagnosis of arterial hypertension. Hypertensive SCAD patients were older (60 ± 12 vs. 51 ± 9 years old) and had more frequently dyslipidemia (56 vs. 23%) and diabetes (9 vs. 3%) but were less frequently smokers (15 vs. 35%) than normotensive SCAD patients (all P < 0.05). Most patients in both groups were female (90 vs. 87%, NS) and female patients with hypertension were more frequently postmenopausal (70 vs. 47%, P < 0.05). Hypertensive SCAD patients had more severe lesions and more frequently multivessel involvement (15 vs. 7%, P < 0.05) and coronary ectasia (19 vs. 7%, P < 0.05) but showed a similar prevalence of coronary tortuosity (34 vs. 26%, NS). Revascularization requirement was similar in both groups (17 vs. 26%, NS) but procedural success was significantly lower (65 vs. 88%, P < 0.05) and procedural-related complications more frequent (65 vs. 41%, P < 0.05) in SCAD patients with hypertension.

CONCLUSION

Patients with SCAD and hypertension are older, more frequently postmenopausal and have more coronary risk factors than normotensive SCAD patients. During revascularization SCAD patients with hypertension obtain poorer results and have a higher risk of procedural-related complications (NCT03607981).

Correlation analysis of coronary artery tortuosity and calcification score

Background

Coronary artery tortuosity (CAT) is regarded as a variation of vascular anatomy, and its relationship with coronary artery calcification (CAC) score is still not well clarified. Studying the correlation between coronary artery calcification scores and CAT to determine specific prevention and intervention populations seems to have more meaningful.

Methods

The study is a cross-sectional retrospective study, including 1280 patients. CAT is defined as the presence of at least three consecutive curvatures of more than 45°measured during systole or diastole of a major epicardial coronary artery. Multivariable regression analysis was used to adjust the clinical parameters directly affecting CAT.

Results

Of these individuals, 445 (35%) were evaluated having CAT, of which females are higher than males (59.1% vs. 40.9%). Moderate CAC score (101–400) (odds ratio (OR) 1.49, 95% confidence interval [95%CI] 1.05–2.10, P = 0.025) revealed significantly associated with CAT on univariable analysis. However, multivariable analysis after adjusting for confounding factors only indicated that CAT was positively correlated with female (OR 1.68, 95%CI 1.30–2.17, P < 0.001), hypertension (OR 1.35, 95% CI 1.04–1.75, P = 0.024), and age (OR 1.02, 95% CI 1.01–1.03, P = 0.001), while was negatively associated with body mass index (BMI) 24–27.9(OR 0.76, 95% CI 0.58–1.00, P = 0.044), and BMI > 28 (OR 0.46, 95% CI 0.31–0.68, P < 0.001). Further analysis stratified by gender showed that compared with non-CAT, CAT was significantly linked with moderate CAC score (OR 1.79, 95% CI 1.00–3.20, P = 0.048), hypertension (OR 1.54, 95% CI 1.07–2.22, P = 0.021), and high-density lipoprotein (HDL) (OR 1.86, 95% CI 1.07–3.24, P = 0.028), while was negatively related to BMI > 28 (OR 0.51, 95% CI 0.31–0.84, P = 0.008) in female patients.

Conclusions

CAT is more likely to be found in females, connected with hypertension, age, and BMI. No significant correlation is found between the presence of tortuosity and calcium score or diameter stenosis on multivariable analysis. Whereas the CAT is associated with moderate CAC score in correlation analysis when women are selected as the main group.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01470-w.

Accuracy of vascular tortuosity measures using computational modelling

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.

Tortuosity Index Calculations in Retinal Images: Some Criticalities Arising from Commonly Used Approaches

A growing body of research in retinal imaging is recently considering vascular tortuosity measures or indexes, with definitions and methods mostly derived from cardiovascular research. However, retinal microvasculature has its own peculiarities that must be considered in order to produce reliable measurements. This study analyzed and compared various derived metrics (e.g., TI, TI_avg, TI*CV) across four existing computational workflows. Specifically, the implementation of the models on two critical OCT images highlighted main pitfalls of the methods, which may fail in reliably differentiating a highly tortuous image from a normal one. A tentative, encouraging approach to mitigate the issue on the same OCT exemplificative images is described in the paper, based on the suggested index TI*CV.

Longitudinal Functional Study of Murine Aging: A Resource for Future Study Designs

Aging is characterized by systemic declines in tissue and organ functions. Interventions that slow these declines represent promising therapeutics to protect against age-related disease and improve the quality of life. In this study, several interventions associated with lifespan extension in invertebrates or improvement of age-related disease were tested in mouse models to determine if they were effective in slowing tissue aging in a broad spectrum of functional assays. Benzoxazole, which extends the lifespan of Caenorhabditis elegans, slowed age-related femoral bone loss in mice. Rates of change were established for clinically significant parameters in untreated mice, including kyphosis, blood glucose, body composition, activity, metabolic measures, and detailed parameters of skeletal aging in bone. These findings have implications for the study of preclinical physiological aging and therapies targeting aging. Finally, an online application was created that includes the calculated rates of change and that enables power and variance to be calculated for many clinically important metrics of aging with an emphasis on bone. This resource will help in future study designs employing novel interventions in aging mice. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

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