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The effects of changes in flow velocity waveform and arterial geometry before and after percutaneous coronary intervention (PCI) in the right coronary artery (RCA) were investigated using computational fluid dynamics. An RCA from a patient with a stenosis was reconstructed based on multislice computerized tomography images. A nonstenosed model, simulating the same RCA after PCI, was also constructed. The blood flows in the RCA models were simulated using pulsatile flow waveforms acquired with an intravascular ultrasound-Doppler probe in the RCA of a patient undergoing PCI. It was found that differences in the waveforms before and after PCI did not affect the time-averaged wall shear stress and oscillatory shear index, but the phase angle between pressure and wall shear stress on the endothelium, stress phase angle (SPA), differed markedly. The median SPA was -63.9[degrees] (range, -204[degrees] to - 10.0[degrees]) for the pre-PCI state, whereas it was 10.4[degrees] (range, -71.1[degrees] to 25.4[degrees]) in the post-PCI state, i.e., more asynchronous in the pre-PCI state. SPA has been reported to influence the secretion of vasoactive molecules (e.g., nitric oxide, [PGI.sub.2], and endothelin-1), and asynchronous SPA ([approximately equal to] -180[degrees]) is proposed to be proatherogenic. Our results suggest that differences in the pulsatile flow waveform may have an important influence on atherogenesis, although associated with only minor changes in the time-averaged wall shear stress and oscillatory shear index. SPA may be a useful indicator in predicting sites prone to atherosclerosis. atherosclerosis; velocity waveform; percutaneous coronary intervention; stress phase angle; computational fluid dynamics

In human heart failure the role of wave generation by the ventricle and wave reflection by the vasculature is contentious. The aim of this study was to compare wave generation and reflection in normal subjects with patients with stable compensated heart failure. Twenty-nine normal subjects and 67 patients with heart failure (New York Heart Association class II or III) were studied by noninvasive techniques applied to the common carotid artery. Data were analyzed by wave intensity analysis to determine the nature and direction of waves during the cardiac cycle. The energy carried by an early systolic forward compression wave (S wave) generated by the left ventricle and responsible for acceleration of flow in systole was significantly reduced in subjects with heart failure (P < 0.001), and the timing of the peak of this wave was delayed. In contrast, reflection of this wave was increased in subjects with heart failure (P < 0.001), but the timing of reflections with respect to the S wave was unchanged. The energy of an expansion wave generated by the heart in protodiastole was unaffected by heart failure. The carotid artery wave speed and the augmentation index did not significantly differ between subjects with heart failure compared with normal individuals. The ability of the left ventricle to generate a forward compression wave is markedly impaired in heart failure. Increased wave reflection serves to maintain systolic blood pressure but also places an additional load on cardiac function in heart failure. cardiac function; blood pressure doi:10.1152/ajpheart.01095.2006

The association between vascular wall shear stress (WSS) and the local development of atherosclerotic plaque makes estimation of in vivo WSS of considerable interest. Three-dimensional ultrasound (3DUS) combined with computational fluid dynamics (CFD) provides a potentially valuable tool for acquiring subject-specific WSS, but the interoperator and intraoperator variability associated with WSS calculations using this method is not known. Here, the accuracy, reproducibility and operator dependence of 3DUS-based computational fluid dynamics were examined through a phantom and in vivo studies. A carotid phantom was scanned and reconstructed by two operators. In the in vivo study, four operators scanned a healthy subject a total of 11 times, and their scan data were processed by three individuals. The study showed that with some basic training, operators could acquire accurate carotid geometry for flow reconstructions. The variability of measured cross-sectional area and predicted shear stress was 8.17% and 0.193 N/[m.sup.2] respectively for the in vivo study. It was shown that the variability of the examined parameters was more dependent on the scan operators than the image processing operator. The range of variability of geometrical and flow parameters reported here can be used as a reference for future in vivo studies using the 3DUS-based CFD approach. Index Terms--Carotid bifurcation, image segmentation, image-based flow measurements, operator dependence, subject-specific modeling, three-dimensional ultrasound (3DUS), 3-D vessel reconstruction, vascular imaging, wall shear stress (WSS).

Excess pressure integral (XSPI), a new index of surplus work performed by the left ventricle, can be calculated from blood pressure waveforms and may indicate circulatory dysfunction. We investigated whether XSPI predicted future cardiovascular events and target organ damage in treated hypertensive individuals. Radial blood pressure waveforms were acquired by tonometry in 2069 individuals (aged, 63±8 years) in the Conduit Artery Functional Evaluation (CAFE) substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). Measurements of left ventricular mass index (n=862) and common carotid artery intima media thickness (n=923) were also performed. XSPI and the integral of reservoir pressure were lower in people treated with amlodipine±perindopril than in those treated with atenolol±bendroflumethiazide, although brachial systolic blood pressure was similar. A total of 134 cardiovascular events accrued during a median 3.4 years of follow-up; XSPI was a significant predictor of cardiovascular events after adjustment for age and sex, and this relationship was unaffected by adjustment for conventional cardiovascular risk factors or Framingham risk score. XSPI, central systolic blood pressure, central augmentation pressure, central pulse pressure, and integral of reservoir pressure were correlated with left ventricular mass index, but only XSPI, augmentation pressure, and central pulse pressure were associated positively with carotid artery intima media thickness. Associations between left ventricular mass index, XSPI, and integral of reservoir pressure and carotid artery intima media thickness and XSPI were unaffected by multivariable adjustment for other covariates. XSPI is a novel indicator of cardiovascular dysfunction and independently predicts cardiovascular events and targets organ damage in a prospective clinical trial. [ABSTRACT FROM AUTHOR]

Background: The effects of monthly, high‐dose, long‐term (≥1‐year) vitamin D supplementation on central blood pressure (BP) parameters are unknown. Methods and Results: A total of 517 adults (58% male, aged 50–84 years) were recruited into a double‐blinded, placebo‐controlled trial substudy and randomized to receive, for 1.1 years (median; range: 0.9–1.5 years), either (1) vitamin D3 200 000 IU (initial dose) followed 1 month later by monthly 100 000‐IU doses (n=256) or (2) placebo monthly (n=261). At baseline (n=517) and follow‐up (n=380), suprasystolic oscillometry was undertaken, yielding aortic BP waveforms and hemodynamic parameters. Mean deseasonalized 25‐hydroxyvitamin D increased from 66 nmol/L (SD: 24) at baseline to 122 nmol/L (SD: 42) at follow‐up in the vitamin D group, with no change in the placebo group. Despite small, nonsignificant changes in hemodynamic parameters in the total sample (primary outcome), we observed consistently favorable changes among the 150 participants with vitamin D deficiency (<50 nmol/L) at baseline. In this subgroup, mean changes in the vitamin D group (n=71) versus placebo group (n=79) were −5.3 mm Hg (95% confidence interval [CI], −11.8 to 1.3) for brachial systolic BP (P=0.11), −2.8 mm Hg (95% CI, −6.2 to 0.7) for brachial diastolic BP (P=0.12), −7.5 mm Hg (95% CI, −14.4 to −0.6) for aortic systolic BP (P=0.03), −5.7 mm Hg (95% CI, −10.8 to −0.6) for augmentation index (P=0.03), −0.3 m/s (95% CI, −0.6 to −0.1) for pulse wave velocity (P=0.02), −8.6 mm Hg (95% CI, −15.4 to −1.9) for peak reservoir pressure (P=0.01), and −3.6 mm Hg (95% CI, −6.3 to −0.8) for backward pressure amplitude (P=0.01). Conclusions: Monthly, high‐dose, 1‐year vitamin D supplementation lowered central BP parameters among adults with vitamin D deficiency but not in the total sample. Clinical Trial Registration URL: http://www.anzctr.org.au. Unique identifier: ACTRN12611000402943.

Dietary salt intake is associated with high brachial blood pressure (BP) and increased risk of cardiovascular disease. We investigated whether changes in dietary salt intake are associated with changes in central BP and wave reflection in healthy volunteers. Ten healthy normotensive male volunteers (22-40 yr) participated in a 6-wk double-blind randomized crossover study to compare a low-dietary salt intake (60-80 mmol sodium/day) with a high-salt intake (low salt intake supplemented with 128 mmol sodium/day) on central BP and wave reflection Brachial and carotid BP, carotid blood flow velocity, forward (Pr) an backward (Pb) pressure, wave intensity, body weight, and urinary electrolyte excretion were measured at the end of each crossover period. High salt intake significantly increased carotid systolic BP [98 (SD 11) vs. 91 mmHg (SD 13), P < 0.01] and increased wa reflection [ratio of backward to forward pressure (Pb/Pf) 0.13 (S 0.02) vs. 0.11 (SD 0.03), P = 0.04] despite only small effects brachial BP [114 (SD 9) vs. 112 mmHg (SD 6), P = 0.1]. Urinary sodium excretion and body weight were also increased following high salt intake. High salt intake disproportionately increases central BP compared with brachial BP as a result of enhanced wave reflection. These effects may contribute to the adverse effect of high dietary salt intake on the risk of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Aims: Patients with controlled hypertension are at risk of future cardiac events, but predicting first events remains difficult. We hypothesized that modern echocardiographic measures of left ventricular diastolic function may be more sensitive than traditional echocardiographic methods of risk prediction and set out to test this in a cohort of patients with well-controlled hypertension. [ABSTRACT FROM PUBLISHER]

This study investigated the possibility of using low-cost, handheld, retinal imaging devices for the automatic extraction of quantifiable measures of retinal blood vessels. Initially, the available handheld devices were compared using a Zeiss model eye incorporating a USAF resolution test chart to assess their optical properties. The only suitable camera of the five evaluated was the Horus DEC 200. This device was then subjected to a detailed evaluation in which images in human eyes taken from the handheld camera were compared in a quantitative analysis with those of the same eye from a Canon CR-DGi retinal desktop camera. We found that the Horus DEC 200 exhibited shortcomings in capturing images of human eyes by comparison with the Canon. More images were rejected as being unevaluable or suffering failures in automatic segmentation than with the Canon, and even after exclusion of affected images, the Horus yielded lower measurements of vessel density than the Canon. A number of issues affecting handheld cameras in general and some features of the Horus in particular have been identified that might contribute to the observed differences in performance. Some potential mitigations are discussed which might yield improvements in performance, thus potentially facilitating use of handheld retinal imaging devices for quantitative retinal microvascular measurements., Competing Interests: We declare we have no competing interests., (© 2023 The Authors.)

Objective: The present study examined the impact of BP from childhood to mid-adulthood on retinal microvascular architecture., Methods: The Cardiovascular Risk in Young Finns Study included children aged 3-18 years, from five Finnish University cities, with participants chosen randomly from the national population registrar from those areas. The age of participants included in the current analyses in childhood (1980) ranged from three to nine years and in mid-adulthood (2011) ranged from 34 to 40 years (complete data n = 657). Measures of retinal microvasculature architecture measured in adulthood included diameters, tortuosity, lengths, and LDR., Results: Regression analysis showed a strong negative association between childhood systolic BP and adult arteriolar diameter (standardized regression coefficient [β] -0.300; p < 0.001) and with change in systolic BP from childhood to adulthood (β = -0.249; p < 0.001). For arteriolar tortuosity, there was a strong positive association between childhood systolic BP and adult arteriolar tortuosity (β = 0.154; p < 0.001) and no association with change in systolic BP from childhood to adulthood (β = 0.072; p = 0.110)., Conclusions: High BP in childhood and increased BP from childhood to adulthood impacts on retinal microvascular architecture in mid-adulthood., (© 2015 John Wiley & Sons Ltd.)

Three-dimensional (3-D) ultrasound is a relatively new technique, which is well suited to imaging superficial blood vessels, and potentially provides a useful, noninvasive method for generating anatomically realistic 3-D models of the peripheral vasculature. Such models are essential for accurate simulation of blood flow using computational fluid dynamics (CFD), but may also be used to quantify atherosclerotic plaque more comprehensively than routine clinical methods. In this paper, we present a spline-based method for reconstructing the normal and diseased carotid artery bifurcation from images acquired using a freehand 3-D ultrasound system. The vessel wall (intima-media interface) and lumen surfaces are represented by a geometric model defined using smoothing splines. Using this coupled wall-lumen model, we demonstrate how plaque may be analyzed automatically to provide a comprehensive set of quantitative measures of size and shape, including established clinical measures, such as degree of (diameter) stenosis. The geometric accuracy of 3-D ultrasound reconstruction is assessed using pulsatile phantoms of the carotid bifurcation, and we conclude by demonstrating the in vivo application of the algorithms outlined to 3-D ultrasound scans from a series of patient carotid arteries.

Background: Patients with pathological left ventricular hypertrophy have depressed midwall systolic shortening in spite of normal indices of left ventricular chamber function and a reduced midwall function has been observed to be an independent predictor of cardiovascular risk. Whether midwall shortening is depressed in physiological hypertrophy is unknown., Methods: Forty-two subjects, 27 athletes and 15 age- and sex-matched normal control subjects (group 1) were studied. The athletes were divided into those with eccentric hypertrophy (group 2) and those with concentric hypertrophy (group 3). Systolic left ventricular function was assessed at the midwall and endocardium using two-dimensional echocardiography in all subjects., Results: Left ventricular mass index was significantly greater in both athletic groups than in controls (group 1, 101+/-5.8 g/m(2), group 2, 141+/-11.1*, group 3, 155+/-5.8*; *P<0.01 compared with group 1). Left ventricular systolic function assessed at the endocardium was similar among all three groups (ejection fraction: group 1, 66.2+/-2.38, group 2, 66.8+/-1.44, group 3, 63.7+/-1.66%; endocardial fractional shortening: group 1, 37.1+/-1.71, group 2, 37.6+/-1.13, group 3, 35.1+/-1.25%). However, fractional shortening at the midwall was reduced in the concentric hypertrophy athletes compared with the other two groups (midwall fractional shortening: group 1, 21.9+/-1.1, group 2, 21.9+/-0.86, group 3, 18.4+/-0.96*%; P<0.05 compared with groups 1 and 2)., Conclusion: Subjects with physiological concentric hypertrophy have depressed midwall fractional shortening. This suggests that the observed discrepancy between midwall and endocardial shortening in patients with left ventricular hypertrophy is likely to be a function of the geometry and not necessarily a reflection of pathology within the myocardium.