Ghazanfar Qureshi

Effect of Reactive Hyperemia on Carotid-Radial Pulse Wave Velocity in Hypertensive Participants and Direct Comparison With Flow-Mediated Dilation: A Pilot Study

This pilot study assessed the effects of hyperemia on carotid-radial pulse wave velocity (PWV) in 39 normotensive (NT) and 23 hypertensive (HT) participants using applanation tonometry. Pulse wave velocity was measured at 1- and at 2-minute intervals. Baseline PWV was similar between the groups (P = .59). At 1 minute, PWV decreased (8.5 ± 1.2 to 7.1 ± 1.4 m/s, P < .001) in NT but not in HT (P = .83). Hyperemic PWV (ΔPWV) response differed between the groups (-16% vs + 1.0%, P < .001). On multivariate analysis, HT, not age or blood pressure was independently related to ΔPWV (R2 = .43, P < .01). Among patients with cardiovascular risk factors/disease, ΔPWV was inversely related to flow-mediated dilation (FMD; R 2 = .43, P < .003). Conclusion: hyperemia decreases PWV1min in NT but not in HT. ΔPWV is inversely related to FMD. Blunted hyperemic PWV response may represent impaired vasodilatory reserve.

Self-measured (blood pressure) arterial stiffness index: A promising new measure of arterial stiffness.

Increased arterial stiffness is predictive of increased cardiovascular risk. The ambulatory arterial stiffness index is a new measure derived from 24-hour ambulatory blood pressure (BP) monitoring. We retrospectively studied 59 consecutive patients, (36 females; age 62 +/- 12 years), evaluated for hypertension in an academic cardiology practice. All had eight or more self-measured BP recorded over a period of 2 through 8 weeks while stable. The self-measured arterial stiffness index (SMASI) was calculated according to the same formula as the ambulatory arterial stiffness index, 1 minus the regression slope of the regression line of diastolic plotted against systolic BP. Mean SMASI was 62 +/- 0.20. SMASI correlated directly with age (r = 0.27; P = .03), BP load (r = 0.40; P = .002), home pulse pressure (r = 0.47; P < .001), and office pulse pressure (r = 0.44; P = .001). SMASI was higher in patients with multiple cardiovascular risk factors and correlated with pulse wave velocity (r = 0.45; P = .04) among 21 patients who underwent arterial tonometry. SMASI correlated with left ventricle (LV) mass/body surface area (BSA) (r = 0.30; P = .035) in 50 patients. SMASI increases with age, is associated with weaker BP control, hypertensive organ damage and correlates with pulse wave velocity. SMASI obtained by self-measured BP may serve as a useful surrogate measure of arterial stiffness.

The effects of head-out-of-water immersion on arterial wave reflection in healthy adults

Swimming/hydrotherapy produces hemodynamic and physiological changes related to water immersion (WI). To evaluate the effects of head out (HO) WI on central hemodynamics, we prospectively studied 21 healthy subjects (62% male, age 37 +/- 13 years). Central aortic blood pressures (CA-BPs) and reflected wave properties were evaluated using applanation tonometry at baseline and upon 2 minutes of waist (W) and mid-chest (C) HOWI. Heart rate (HR) decreased from 83 +/- 15 to 73 +/-10 beats/min (P < .001). Brachial artery pulse pressure (PP) was unchanged (45 +/- 11 to 46 +/- 7 mm Hg; P = .20), CA-PP increased stepwise (27 +/- 7 to 32 +/- 8 to 33 +/- 6 mm Hg; P < .001). Reflected wave amplitude (P(s) - P(i)), and HR-corrected augmentation index (AI(a)@75) increased stepwise from baseline-W-C level HOWI [(P(s) - P(i)): 2 +/- 3 to 7 +/- 4 mm Hg, P < .001; AI(a)@75: 8 +/- 11 to 19 +/- 10%; P < .001]. HR-corrected ejection duration (ED(c)) and reflected wave systolic duration (Deltat(r)) increased progressively (ED(c): 389 +/- 23 to 408 +/- 25 to 435 +/- 13 milliseconds; P < .001; Deltat(r): 106 +/- 32 to 165 +/- 21 ms; P < .001). Indices of left ventricular (LV) workload including wasted LV energy subendocardial viability and tension time index increased upon HOWI. HOWI increases the amplitude and the duration of the reflected aortic pressure wave, increases wasted LV pressure energy, workload, and oxygen demand.

Bone Mineral Density as a Predictor of Atherosclerosis and Arterial Wall Stiffness in Obese African-American Women

Bone demineralization is associated with higher cardiovascular event rates, possibly due to vascular calcification and accelerated atherosclerosis. African-Americans have less bone loss and less calcium content within atherosclerotic plaques. However, whether loss of bone mass is related to atherosclerosis has not been examined in African-Americans. The objective of this study was to evaluate possible associations between bone mineral density (BMD), carotid intimal-medial thickness (CIMT), and arterial stiffness. We studied 100 obese African-American women (BMI: 26.6 ± 6.2; age: 63 ± 14 years) referred for BMD estimation by dual-energy X-ray absorptiometry scan. BMD (g/cm2) was obtained at the lumbar spine (L1–L4), femoral neck, and total hip. Arterial stiffness was evaluated by the heart rate-corrected augmentation index (AI@75) and pulse wave velocity (PWV) using applanation tonometry. CIMT was measured by vascular ultrasound. Mean CIMT, AI@75, and PWV were 0.72 ± 0.14 mm, 28.8 ± 9.0%, and 8.9 ± 1.6 m/s, respectively. Mean BMD values at the lumbar spine, femoral neck, and hip were 0.96 ± 0.19, 0.80 ± 0.16, and 0.91 ± 0.17 g/cm2. Older subjects had higher CIMT (r = 0.61, p < 0.001) and AI@75 (r = 0.42, p < 0.001). There was a significant correlation between AI@75 and CIMT (r = 0.45, p < 0.001). BMD was negatively correlated with AI@75 (lumbar: r = –0.22, p = 0.03; femoral neck: r = –0.24, p = 0.01; hip: r = –0.21, p = 0.03). BMD was unrelated to CIMT (lumbar: r = –0.09, p = 0.42; femoral neck: r = –0.15, p = 0.17; hip: r = –0.13, p = 0.23). On multivariate analysis, age (p < 0.001), hypertension (p = 0.02), and lumbar BMD (p = 0.01, R2 = 0.30) were independent predictors of increased AI@75 after adjusting for age, height, and cardiovascular risk factors. These findings were unchanged upon substitution of femoral neck BMD (p = 0.05, R2 = 0.28) into the model. There was a trend with hip BMD (p = 0.06, R2 = 0.28) in the regression model. Age-matched comparison between normal BMD (n = 25) and osteoporotic patients (n = 34) demonstrated a significant difference in AI@75 (26.6 ± 8.9 vs. 31.6 ± 9.1%, p = 0.04). In summary, women with lower BMD had increased arterial stiffness. There was no relationship between BMD and atherosclerosis. In conclusion, age, hypertension, and BMD are independent predictors of higher arterial stiffness. Vascular changes are related to bone mineral loss, suggesting lower BMD may increase cardiovascular risk in African-Americans.

Left Ventricular Systolic and Diastolic Function in Healthy Adult Bonnet Macaques (Macaca radiata)

Objectives: Macaques are used in cardiovascular and metabolic research. We determined echocardiographic-derived reference values of left ventricular (LV) systolic and diastolic function in healthy adult bonnet macaques (Macaca radiata). Methods: Transthoracic echocardiography was performed during ketamine sedation in 83 (67% female) healthy monkeys (age 7–26 years). Results: Technically adequate studies were obtained in all subjects and required 10.1 ± 1.3 min of scanning time. Age correlated inversely with the following Doppler indices: E (r = –0.44, p < 0.001), E/A (r = –0.26, p = 0.02), E′ (r = –0.45, p < 0.001, E′/A′ (r = –0.44, p < 0.001), E/E′ (r –0.25, p = 0.03), S′ (r = –0.33, p = 0.003), Vp (r = –0.26, p = 0.049). LV mass was more strongly correlated with crown rump length (r = 0.72, p < 0.001) and body surface area (r = 0.70, p < 0.001) than with body mass index (r = 0.47, p < 0.001) and weight (r = 0.63, p < 0.001). Conclusions: This study demonstrates echocardiography is feasible for characterizing LV function. Age-related changes in Doppler indices in primates are similar to those in humans. LV mass is more closely related to fat-free mass indices. We provide reference values for LV systolic and diastolic function in adult bonnet macaques across the captive life span.

The Relationship Between Effective Arterial Capacitance and Pulse Wave Velocity Is Dependent on Left Ventricular Stroke Volume

Background: increased arterial stiffness is a predictor of cardiovascular events. The stroke volume (SV) to pulse pressure (PP) ratio is an estimate of arterial capacitance. Pulse wave velocity (PWV) is a measure of arterial stiffness. This study evaluated the effect of left ventricular (LV) SV on the SV/PP—PWV relationship. Methods: 97 patients had applanation tonometry and echocardiography to measure arterial capacitance (SV/PP), PWV, and central aortic pressure. Results: 50 patients had normal SV and 47 had low SV. For all patients, PWV inversely correlated with SV/PP. PWV and SV/PP correlated more strongly in the normal SV group than in the low SV group. Aortic PP was significantly correlated with PWV in all patients, in the normal SV group, and in the low SV group. Conclusion: effective arterial capacitance correlates with PWV. The presence of decreased SV weakens the relationship.

Relationship Between Aortic Atherosclerosis and Dental Loss in an Inner-City Population

Prior studies have suggested an association between atherosclerosis and periodontal disease, both of which are more prevalent in certain minority and economically disadvantaged groups. Few studies have addressed the relationship between cardiovascular disease and dentition among ethnically diverse populations. We studied 131 subjects (60% females, age 59 ± 15 years) who were referred for clinically indicated transesophageal echocardiography. Dental loss was more severe in patients with hypertension (P < .001), diabetes (P = .05), coronary artery disease (P = .04), and calcium channel blocker use (P = .04). On univariate analysis, maximal aortic intima—media thickness (MAIMT) was significantly correlated with dental loss (r = .40; P < .001). Age was correlated with MAIMT (R = .41; P < .001) and with dental loss (r = .57; P < .001). On multivariate analysis, dental loss (P = .03) and history of coronary artery disease (P = .04) were independent predictors of MAIMT ( R 2 = .44). In this inner-city predominantly African American population, atherosclerosis and dental loss are age dependent and are interrelated independent of age.

Association of beta-blocker use with increased aortic wave reflection

Studies have found less cardiovascular risk reduction in patients treated with beta-blockers (BBs) compared with other agents. We compared the severity of aortic atherosclerosis, arterial stiffness, and wave reflection in patients treated and not treated with BBs. Seventy-two patients, 37 treated with BBs and 35 not treated, referred for transesophageal echocardiography were studied. Augmentation index (AI), heart-rate-corrected AI (AI-75), aortic systolic (SBP) and diastolic blood pressure, pulse wave velocity (PWV), and aortic intima-media thickness (MAIMT) were measured. There were no differences in MAIMT (2.8 +/- 1.6 mm vs. 2.4 +/- 1.2 mm, P = .20) and PWV (8.9 +/- 2.0 m/s vs. 8.5 +/- 2.6 m/s, P = .46) between the BB and non-BB groups. The BB group had higher AI (28.7 +/-11.9% vs. 22.3 +/- 14.1%, P = .04), AI-75 (27.7 +/- 10.7% vs. 20.1+/- 11.0%, P = .005), aortic SBP (140 +/- 21 mm Hg vs. 125 +/- 21 mm Hg, P = .01), and aortic pulse pressure (62 +/- 20 mm Hg vs. 47 +/- 19 mm Hg, P = .01) than the non-BB group despite similar brachial blood pressure. BB use was associated with increased aortic wave reflection despite similar degree of aortic atherosclerosis.

Characterization of Arterial Wave Reflection in Healthy Bonnet Macaques: Feasibility of Applanation Tonometry

Nonhuman primates are commonly used in cardiovascular research. Increased arterial stiffness is a marker of subclinical atherosclerosis and higher CV risk. We determined the augmentation index (AI) using applanation tonometry in 61 healthy monkeys (59% female, age 1–25 years). Technically adequate studies were obtained in all subjects and required 1.5 ± 1.3 minutes. The brachial artery provided the highest yield (95%). AI was correlated with heart rate (HR) (r = −0.65, P < .001), crown rump length (CRL) (r = 0.42, P = .001), and left ventricular (LV) mass determined using echocardiography (r = 0.52, P < .001). On multivariate analysis, HR (P < .001) and CRL (P = .005) were independent predictors of AI (R2 = 0.46, P < .001). Body Mass Index (BMI) and AI were independent predictors of higher LV mass on multivariate analysis (P < .001 and P = .03). In conclusion, applanation tonometry is feasible for determining AI. Reference values are provided for AI in bonnet macaques, in whom higher AI is related to HR and CRL, and in turn contributes to higher LV mass.

Indices of Arterial Stiffness in African American and African Caribbean Subjects

BACKGROUND African American and African Caribbeans have high cardiovascular morbidity/mortality. Increased arterial stiffness is a marker of subclinical atherosclerosis, predicts higher cardiovascular risk, and causes isolated systolic hypertension. The objectives of the study were to compare arterial stiffness indices in African Americans and African Caribbeans and obtain reference values. METHODS/RESULTS We prospectively studied 449 African Americans and 454 African Caribbeans. Using applanation tonometry, mean augmentation index and carotid-to-radial pulse-swave velocity were similar between the 2 groups (23 +/- 15 vs 24 +/- 14%, p = .20) and (9.0 +/- 1.9 vs 9.0 +/- 2.0 m/s, p = .86). On multivariate analysis, age, weight, gender, mean arterial pressure, heart rate, and family history of coronary artery disease were independently associated with augmentation index in African Americans (R2, 0.46) and African Caribbeans (R2, 0.49). Among 94 African American and 98 African Caribbean healthy subjects without cardiovascular risk factors/disease, augmentation index (20 +/- 14 vs 18 +/- 16%, p = .43) and pulse-wave velocity (8.9 +/- 1.9 vs 9.0 +/- 1.5 m/s, p = .92) were similar. Age-based normative values were determined. CONCLUSION Augmentation index and pulse-wave velocity and their related clinical factors are similar between African Americans and African Caribbeans. Age, weight, female gender, mean arterial pressure, heart rate, and family history of coronary artery disease are independent predictors of higher augmentation index in African Americans and African Caribbeans. Whether increased arterial stiffness improves risk stratification in these populations merits further study.