Background: Excess atherosclerotic cardiovascular disease (ASCVD) risk in people with human immunodeficiency virus (HIV) infection may be related to inflammation and disordered immune regulation. W...
Ultrasound based Lagrangian carotid strain imaging (LCSI) utilizes physiological deformation caused by arterial pressure variations to generate strain tensor images. We have previously demonstrated the ability of maximum accumulated strain indices (MASI) and peak-to-trough indices derived from these corresponding strain tensor images to quantify carotid plaque vulnerability thereby enhancing their utility as vascular biomarkers. However, a critique of LCSI has been the lack of normalization of MASI and peak-to-trough strain indices to the physiological stimuli, namely the blood pressure. We report in this paper on the impact of normalization of these strain indices to blood pressure measurements. The blood pressure measurements are acquired immediately after the acquisition of radiofrequency data loops for strain imaging and carotid ultrasound images. All imaging was performed on human patients scheduled for a carotid endarterectomy (CEA) procedure (n=44 patients). Patients were further identified as symptomatic or asymptomatic based on clinical symptoms. Cognition was also assessed on these patients using the 60-minute neuropsychological test protocol following guidelines of the National Institute of Neurological Disorders and Canadian Stroke Network. Blood pressure measurements were utilized to normalize strain indices estimated from the axial, lateral and shear strain images over two cardiac cycles using systolic, diastolic and maximum arterial pressure (MAP) respectively. No significant differences in the area under the curve (AUC) estimates were obtained between MASI and peak-to-trough strain indices that were normalized to the systolic, diastolic, pulse pressure and maximum arterial pressure when compared to the unnormalized results reported previously. Although small improvements in the correlation of the strain indices with cognition parameters and AUC values were obtained with normalization, unnormalized strain indices on their own provided a significant correlation with the reduction in executive function reported with cognitive testing. For axial strain, the correlation of peak values with cognition were -0.49, -0.47, -0.5 and -0.49 for unnormalized, systolic, diastolic and MAP normalization respectively. The corresponding AUC values for classifiers designed using the maximum likelihood estimation model were 0.75, 0.73, 0.75, and 0.73 respectively.
Background: In individuals with peripheral artery disease (PAD), supervised treadmill exercise improves walking performance. We performed an exploratory analysis to evaluate the biological effects ...
There is increasing evidence that vascular disease risk factors contribute to evolution of the dementia syndrome of Alzheimer's disease (AD). One important measure of cerebrovascular health is pulsatility index (PI) which is thought to represent distal vascular resistance, and has previously been reported to be elevated in AD clinical syndrome. Physical inactivity has emerged as an independent risk factor for cardiovascular disease.This study aims to examine the relationship between a measure of habitual physical activity, cardiorespiratory fitness (CRF), and PI in the large cerebral vessels.Ninety-two cognitively-healthy adults (age = 65.34±5.95, 72% female) enrolled in the Wisconsin Registry for Alzheimer's Prevention participated in this study. Participants underwent 4D flow brain MRI to measure PI in the internal carotid artery (ICA), basilar artery, middle cerebral artery (MCA), and superior sagittal sinus. Participants also completed a self-report physical activity questionnaire. CRF was calculated using a previously-validated equation that incorporates sex, age, body-mass index, resting heart rate, and self-reported physical activity. A series of linear regression models adjusted for age, sex, APOE4 status, and 10-year atherosclerotic cardiovascular disease risk were used to analyze the relationship between CRF and PI.Inverse associations were found between CRF and mean PI in the inferior ICA (p = .001), superior ICA (p = .035), and basilar artery (p = .040). No other cerebral vessels revealed significant associations between CRF and PI (p≥.228).Higher CRF was associated with lower PI in several large cerebral vessels. Since increased pulsatility has been associated with poor brain health and reported in persons with AD, this suggests that aerobic fitness might provide protection against cerebrovascular changes related to the progression of AD clinical syndrome.
Patients with human immunodeficiency virus (HIV) receiving antiretroviral therapy (ART) are at increased risk of cardiovascular disease (CVD). In HIV-infected patients on ART, abnormalities of serum lipoproteins and insulin resistance have been associated with endothelial dysfunction. However, the effects of ART on dyslipidemia and CVD risk have been difficult to study because of the complexity of ART regimens and varying metabolic effects between and within ART classes. This study evaluated the effects of three ART regimens on lipids and lipoproteins, markers of insulin and glucose metabolism, and endothelial function. This was a substudy of A5142, a prospective, multicenter study of 82 treatment-naïve HIV-infected individuals randomly assigned to receive one of 3 class-sparing HIV treatment regimens: nucleoside reverse transcriptase inhibitors (NRTIs) + the non-nucleoside reverse transcriptase inhibitor efavirenz, NRTIs + the protease inhibitor lopinavir/ritonavir (LPV/r), or NRTI-sparing regimen of efavirenz + LPV/r. Lipoprotein particle concentrations were measured by nuclear magnetic resonance spectroscopy. Endothelial function was evaluated by brachial artery flow-mediated vasodilation (FMD) at baseline and after 24 weeks. All values are medians (interquartile range). Total and small low-density lipoprotein concentrations increased by 152 (−49, +407, p<0.01) and 130 (−98, +417, p<0.01) nmol/L, respectively, especially in the 0.04). Very low-density lipoproteins also increased (p+0.01), with larger increases in the arms that contained LPV/r (p KW 0.022). High-density lipoproteins increased by 6.0 mcmol/L (+2.8, +10.4, p<0.01), similarly in each arm. FMD increased by 1.48% (−0.20, +4.30%, p<0.001) with similar changes in each arm. Changes in lipoproteins were not related to changes in markers of insulin/glucose metabolism or FMD. Effective ART is associated with increases in total and small low-density lipoproteins and very low-density lipoproteins, especially in regimens that contain LPV/r. Over 24 weeks, the vascular effects of ART-related lipid changes may be outweighed by beneficial effects on treatment of HIV infection.
