Speckle tracking carotid artery circumferential strain is a marker of arterial sclerosis but not coronary atherosis

A spatiotemporal analysis of the left coronary artery biomechanics using fluid-structure interaction models

Biomechanics plays a critical role in coronary artery disease development. FSI simulation is commonly used to understand the hemodynamics and mechanical environment associated with atherosclerosis pathology. To provide a comprehensive characterization of patient-specific coronary biomechanics, an analysis of FSI simulation in the spatial and temporal domains was performed. In the current study, a three-dimensional FSI model of the LAD coronary artery was built based on a patient-specific geometry using COMSOL Multiphysics. The effect of myocardial bridging was simulated. Wall shear stress and its derivatives including time-averaged wall shear stress, wall shear stress gradient, and OSI were calculated across the cardiac cycle in multiple locations. Arterial wall strain (radial, circumferential, and longitudinal) and von Mises stress were calculated. To assess perfusion, vFFR was calculated. The results demonstrated the FSI model could identify regional and transient differences in biomechanical parameters within the coronary artery. The addition of myocardial bridging caused a notable change in von Mises stress and an increase in arterial strain during systole. The analysis performed in this manner takes greater advantage of the information provided in the space and time domains and can potentially assist clinical evaluation.

Evaluating Atherosclerosis of the Abdominal Aorta in Rabbits Using 2-D Strain Imaging

After establishment of an animal model of atherosclerosis, speckle tracking imaging was performed to analyze the correlation between ultrasound characteristics and pathological manifestations. Rabbits were divided into the normal control (NC) and atherosclerosis (AS) groups. Rabbits in the AS group were subjected to ultrasound-guided balloon injury of the abdominal aorta and fed a high-fat diet for 16 wk. Rabbits in the NC group were fed a normal diet for the same period. After 16 wk, all animals underwent serological tests, ultrasound and speckle tracking circumferential strain analysis. In the AS group, 28 hypo-echoic plaques had formed. The circumferential strain of six segments at the short axis of plaques in the AS group was lower than that in the NC group (p < 0.001), and global circumferential strain (GCS) in the AS group was significantly reduced compared with the NC group (p < 0.001). In the AS group, the area ratio of type I to type III collagen fibers was smaller than that in the NC group. The GCS of atherosclerotic plaques was positively correlated with the area ratio of type I to type III collagen fibers in plaques (r = 0.7181, p < 0.001). In conclusion, there is a significant positive correlation between the decreased circumferential strain and the decreased area ratio of type I to type III collagen fibers in hypo-echoic plaques.

Increased carotid artery stiffness after preeclampsia in a cross-sectional study of postpartum women

Preeclampsia (PE) is a hypertensive obstetrical complication associated with increased cardiovascular disease risk. Carotid artery functional assessments allow for identification of subclinical vascular dysfunction. This cross‐sectional study measured carotid artery functional indices in healthy women with a recent pregnancy complicated by PE, versus women with a prior uncomplicated pregnancy. Women with a history of PE (N = 30) or an uncomplicated pregnancy (N = 30), were recruited between 6 months and 5 years postpartum. Left and right carotid artery ultrasound measured carotid intima media thickness, plaque burden, peak systolic velocity, end diastolic flow velocity and carotid far‐wall circumferential strain (FWCS). Carotid FWCS is inversely related to vessel stiffness, where a decrease in FWCS indicates increased vessel stiffness. Right‐side FWCS did not differ between women with a history of PE versus normotensive pregnancy. Left carotid artery FWCS was lower in formerly preeclamptic women after adjustment for diameter, pulse pressure, and heart rate compared to women following an uncomplicated pregnancy (3.35 ± 1.08 × 10⁻³ vs. 4.46 ± 1.40 × 10⁻³; p = 0.003). Those with prior severe PE had the greatest decrease in FWCS adjusted to diameter, pulse pressure, and heart rate compared to healthy controls (p = 0.02). Adjusted FWCS and total serum cholesterol were independent indicators of PE history when present in a logistic regression model with confounding variables including age, body mass index, and resting blood pressure. Further investigation is needed to elucidate if FWCS can be used as a risk stratification tool for future cardiovascular disease following a pregnancy complicated by PE. A history of PE is associated with decreased left FWCS (increased left carotid artery stiffness).

Evaluation of Intima-Media Thickness and Arterial Stiffness as Early Ultrasound Biomarkers of Carotid Artery Atherosclerosis

Carotid atherosclerosis is a major and potentially preventable cause of ischemic stroke. It begins early in life and progresses silently over the years. Identification of individuals with subclinical atherosclerosis is needed to initiate early aggressive vascular prevention. Although carotid plaque appears to be a powerful predictor of cardiovascular risk, carotid intima-media thickness (CIMT) and arterial stiffness can be detected at the initial phases and, therefore, they are considered important new biomarkers of carotid atherosclerosis. There is a well-documented association between CIMT and cerebrovascular events. CIMT provides a reliable marker in young people, in whom plaque formation or calcification is not established. However, the usefulness of CIMT measurement in the improvement of risk cardiovascular models is still controversial. Carotid stiffness is also significantly associated with ischemic stroke. Carotid stiffness adds value to the existing risk prediction based on Framingham risk factors, particularly individuals at intermediate cardiovascular risk. Carotid ultrasound is used to assess carotid atherosclerosis. During the last decade, automated techniques for sophisticated analysis of vascular mechanics have evolved, such as speckle tracking, and new methods based on deep learning have been proposed with promising outcomes. Additional research is needed to investigate the imaging-based cardiovascular risk prediction of CIMT and stiffness.

Carotid vascular strain predicts cardiovascular events in patients with hypertension

BACKGROUND

We aim to investigate prognostic effects of carotid strain (CS) and strain rate (CSR) in hypertension.

METHODS

We prospectively recruited 120 patients being treated for hypertension (65.8 ± 11.8 years, 58% male) in this observational study. Peak circumferential CS and peak CSR after ejection were identified using two-dimensional speckle tracking ultrasound. Major cardiovascular events were any admission for stroke, acute coronary syndrome, and heart failure.

RESULTS

After a mean follow-up period of 63.6 ± 14.5 months, 14 (12%) patients had cardiovascular events. Age (75.3 ± 9.2 vs 64.6 ± 11.6 years; p = 0.001), systolic blood pressure (131.8 ± 15.5 vs 143.1 ± 16.6 mm Hg; p = 0.021), diastolic blood pressure (74.6 ±11.4 vs 82.1 ± 12.2 mm Hg; p = 0.039), use of diuretics (71 vs 92%; p = 0.014), carotid CS (2.17 ± 1.02 vs 3.28 ± 1.14 %; p = 0.001), and CSR (.28 ± .17 vs .51 ± .18 1/s; p < 0.001) were significantly different between the patients who did and did not reach the end-points. Multivariate Cox regression analysis controlling for age, systolic blood pressure, diastolic blood pressure, and use of diuretics showed that CS (HR .425, 95%CI .223-.811, p = 0.009) and CSR (HR .001, 95%CI .000-.072, p = 0.001) were independent predictors for cardiovascular events.

CONCLUSION

In conclusions, decreased CS and CSR were associated with cardiovascular events in hypertension.

Carotid arterial mechanics as useful biomarker of extracellular matrix turnover and preserved ejection fraction heart failure

Aims

We aimed to investigate the functional alterations, diagnostic utilization, and prognostic implication of carotid arterial deformations in subjects with cardiovascular risk factors and heart failure (HF) with preserved ejection fraction (HFpEF).

Methods and results

Among 251 prospectively participants (mean age 66.0 ± 9.8 years, 65.7% female) in a single centre between December 2011 and September 2014, carotid artery deformations including circumferential strain (CCS)/strain rate and radial strain were analysed by two‐dimensional speckle tracking. We further related these carotid artery deformation indices to HF biomarkers and cardiac structure and function by echocardiography and explored their prognostic values. Significant reductions of CCS, circumferential strain rate, and circumferential radial strain were observed across control (n = 52), high risk (n = 147), and HFpEF (n = 52) (trend P ≤ 0.001). Aging, hypertension, HFpEF, and higher pulse rate showed independent associations with reduced CCS by stepwise multivariate regressions (all P < 0.05). Higher CCS was inversely associated with better cardiac remodelling and functional indices, and lower multiple HF biomarkers (all P ≤ 0.005). After adjustment, higher CCS was independently associated with better global ventricular longitudinal strain/early diastolic strain rate, lower matrix metalloproteinase‐2, and N‐terminal propeptide of procollagen type III levels (adjusted coef: −0.08 and −19.9, all P < 0.05). During a median follow‐up of 1406 days (interquartile range: 1342‑1720 days), CCS less than 3.28% as a cut‐off had markedly higher HF events [Harrell's C: 0.72, adjusted HR: 2.20 (95% confidence interval: 1.24, 3.16), P = 0.008]. CCS also showed significantly improved risk prediction for HF over global ventricular longitudinal strain (net reclassification index: 48%, P = 0.001; integrated discrimination improvement: 1.8%, P < 0.001).

Conclusions

Carotid artery deformations using two‐dimensional speckle‐tracking imaging showed novel mechanistic insights on functional arterial alterations reflecting coupled arterial‐ventricular pathophysiology. Utilization of such measure may further provide additive prognostic value to advanced myocardial functional assessment.