Association Between Thoracic Aorta Calcium and Thoracic Aorta Geometry in a Cohort of Asymptomatic Participants at Increased Cardiovascular Risk

Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models

Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.

Calcification prevalence in different vascular zones and its association with demographics, risk factors, and morphometry

Vascular calcification is associated with a higher incidence of cardiovascular events, but its prevalence in different vascular zones and the influence of demographics, risk factors, and morphometry remain insufficiently understood. Computerized tomography angiography scans from 211 subjects 5-93 yr old (mean age 47 ± 24 yr, 127 M/84 F) were used to build 3D vascular reconstructions and measure arterial diameters, tortuosity, and calcification volumes in six vascular zones spanning from the ascending thoracic aorta to the pelvic arteries. A machine learning random forest algorithm was used to determine the associations between calcification in each zone with demographics, risk factors, and vascular morphometry. Calcification appeared during the fourth decade of life and was present in all subjects after 65 yr. The abdominal aorta and the iliofemoral segment were the first to develop calcification, whereas the ascending thoracic aorta was the last. Demographics and risk factors explained 33-59% of the variation in calcification. Age, creatinine level, body mass index, coronary artery disease, and hypertension were the strongest contributors, whereas the effects of sex, race, tobacco use, diabetes, dyslipidemia, and alcohol and substance use disorders on calcification were small. Vascular morphometry did not directly and independently affect calcium burden. Vascular zones develop calcification asynchronously, with distal segments calcifying first. Understanding the influence of demographics and risk factors on calcium prevalence can help better understand the disease pathophysiology and may help with the early identification of patients that are at higher risk of cardiovascular events.NEW & NOTEWORTHY We investigated the prevalence of vascular calcification in different zones of the aorta and pelvic arteries using computerized tomography angiography reconstructions and have applied machine learning to determine how calcification is affected by demographics, risk factors, and morphometry. The presented data can help identify patients at higher risk of developing vascular calcification that may lead to cardiovascular events.

Sex differences in left ventricular afterload and diastolic function are independent from the aortic size

Background

Women have a greater risk of heart failure with preserved ejection fraction (HFPEF) than men do, yet the basis for this disparity remains unclear. Greater arterial stiffness and afterload causes left ventricular (LV) diastolic dysfunction, a central mechanism of HFPEF. Because of smaller body habitus, previous reports have used body surface area as a surrogate of the size of the aorta. We performed a comprehensive hemodynamic evaluation of elderly patients with preserved EF and evaluated sex differences in the associations between LV function and afterload, before and after adjusting for the aortic sizes.

Methods and results

Four hundred and forty-three patients (mean age: 73 years, 169 women) who underwent clinically indicated echocardiography and computed tomography (CT) were identified. Linear regression analyses were performed to assess the independent contributions of sex to and its interaction with LV function before and after adjusting for CT-derived aortic length and volume. Although blood pressures were similar between the sexes, women had greater arterial elastance, lower arterial compliance, and greater LV ejection fraction (all p<0.001). Sex differences were detected in the associations between LV afterload and relaxation (mitral e′) as well as in the left atrial (LA) emptying fraction, but not in LA size. These differences remained significant after adjusting for the aortic length and volume. Sensitivity analyses in an age-matched subgroup (n = 324; 162 of each sex) confirmed the robustness of these sex disparities in LV diastolic function and afterload.

Conclusion

Women had worse LV relaxation than men did against the same degree of afterload, before and even after adjusting for the aortic sizes.

The Relationship between Heart Rate Variability and Aortic Knob Width

BACKGROUND

The aortic knob width (AKW) and the heart rate variability (HRV) were suggested to be related to development of cardiovascular diseases. However, the relationship between them has not been investigated; thus, this study aimed to determine this relationship.

METHODS

This study included 587 Koreans aged 18-79 years. Their physical measurements, medical and social histories, blood test findings, and chest radiographs were obtained. The HRV parameters included the standard deviation of the N-N interval (SDNN), root mean square of successive differences (RMSSD), approximate entropy (ApEn), total power (TP), very low frequency (VLF), low frequency (LF), high frequency (HF), and LF/HF ratio, which were measured for 5 minutes. The AKW was measured on chest radiographs by a single reviewer.

RESULTS

The AKW was significantly correlated with the HRV parameters, except for the LF/HF ratio. However, RMSSD and ApEn were not significantly related to the AKW in women. After dividing the participants into quartile groups, the AKW was significantly related to the SDNN, RMSSD, TP, VLF, LF, and HF. The HRV parameter values decreased in the higher AKW quartile groups, the HRV parameter values decreased. After adjusting for sex, drinking status, exercise habits, smoking status, waist circumference, and triglyceride, low-density lipoprotein cholesterol, fasting blood sugar, and glycated hemoglobin levels, the AKW showed significant negative associations with the HRV parameters, except for the LF/HF ratio.

CONCLUSION

The AKW is significantly associated with the HRV parameters of SDNN, RMSSD, ApEn, TP, VLF, LF, and HF.

Atherosclerotic plaque burden evaluated from neck to groin: effect of gender and cardiovascular risk factors

We explored the impact of gender and cardiovascular risk factors (RF) in the distribution and burden of coronary and extra-coronary atherosclerotic plaques among patients undergoing ECG-gated thoracoabdominal computed tomography angiography (CTA) from the supra-aortic trunks to the femoral arteries. We included a consecutive cohort of patients who underwent ECG-gated thoracoabdominal aortic CTA from the supra-aortic trunks to the pubic symphysis. We evaluated the number of coronary segments with plaques [segment-involvement score (SIS)]; and the extra-coronary atherosclerotic plaque burden, comprising the aorta and supra-aortic trunks, iliofemoral arteries, and visceral arteries (extra-coronary SS). A total of 3400 vascular segments were evaluated in 100 patients (mean age 67.0 ± 12.6 years, 66% male). Seventy-two (72%) patients had evidence of atherosclerosis in the coronary tree (coronary SIS ≥ 1), of which 32% was extensive (coronary SIS > 5). Males had a significantly higher prevalence of coronary SIS ≥ 1 [53 (80%), vs. 19 (56%), p = 0.018], and coronary SIS > 5 [24 (36%) vs. 8 (24%), p = 0.035] than females. Extra-coronary SS was similar between genders (males 10.2 ± 5.8 vs. females 9.7 ± 5.4, p = 0.70), irrespective of the location along the different vascular beds. The number of coronary RF was significantly related to the coronary SIS (p = 0.038), and hypertension and diabetes were consistently related to coronary and extra-coronary plaque burden. In the present study involving analysis of multiple vascular beds from the supra-aortic trunks to the femoral arteries, we identified significant sex-related differences in coronary plaque burden, whereas extra-coronary plaque burden was similar between genders irrespective of the vascular bed assessed.