Time Rate Of Blood Pressure Variation Research Articles

ASSOCIATION OF SHORT-TERM VARIABILITY INDICES WITH COMMON CAROTID ARTERY INTIMA-MEDIA THICKNESS IN NORMOTENSIVE AND HYPERTENSIVE SUBJECTS

Objective: Most studies have demonstrated that increased blood pressure (BP) variability is associated with target-organ damage development and cardiovascular events even after adjusting for average BP levels. Although several BP variability indices have been used for measuring BP variability, the few studies that directly compared the prognostic value of different estimates of BP variability did not provide clear indications as to which index should be preferred. Aim of the study was to compare the association between ambulatory BP variability indices and common carotid artery intima-media thickness (CCA-IMT) in normotensive and hypertensive subjects. Design and method: A total of 977 subjects, referred for evaluation at the Hypertension Unit of our department, underwent 24-h ambulatory blood pressure (BP) monitoring and CCA-IMT ultrasonographic measurements. Short-term BP variability was expressed by standard deviation (SD), time rate of BP variation (TR), average real variability (ARV) and coefficient of variation (CV) of systolic and diastolic BP for both 24-h, daytime and nighttime intervals. All subjects were divided according to the 24-hour BP levels to normotensives (24-hour BP<130/80 mmHg) and hypertensives (24-hour BP>=130/80 mmHg). Statistical analysis was performed by means of bivariate correlations, simple and multiple linear regression analysis. Results: The study population consisted of 464 (47%) normotensive and 513 (53%) hypertensive subjects. In normotensive individuals 24-hour systolic TR (r = 0.184, p < 0.001), 24-hour systolic ARV (r = 0.202, p < 0.001) and diastolic ARV (r = 0.093, p = 0.046) were significantly correlated with CCA-IMT. In hypertensive patients 24-hour systolic TR (r = 0.212, p < 0.001), 24-hour systolic ARV (r = 0.226, p < 0.001) and 24-hour systolic SD (r = 0.088, p = 0.046) significantly correlated with CCA-IMT. The multivariate analysis revealed that 24-hour systolic TR of BP variation and 24-hour systolic ARV were significantly and independently associated with CCA-IMT even after adjustment for 24-hour systolic BP. Conclusions: Systolic ambulatory BP variability indices such as SD, TR and ARV are associated with CCA-IMT in normotensive and hypertensive subjects. 24-hour systolic TR of BP variation and ARV are significantly associated with CCA-IMT independently of average BP levels.

ASSOCIATION OF SHORT-TERM VARIABILITY INDICES WITH COMMON CAROTID ARTERY INTIMA-MEDIA THICKNESS IN CHRONIC KIDNEY DISEASE PATIENTS

Objective: Several studies have demonstrated that increased blood pressure (BP) variability is associated with target-organ damage development in hypertensive patients. However, the impact of short-term BP variability indices on target-organ damage in chronic kidney disease patients (CKD) is unclear. Aim of the study was to evaluate the association between ambulatory BP variability indices and common carotid artery intima-media thickness (CCA-IMT) in chronic kidney disease patients. Design and method: A total of 83 CKD patients, referred for evaluation at the Hypertension Unit of our department, underwent 24-h ambulatory blood pressure (BP) monitoring and CCA-IMT ultrasonographic measurements. Short-term BP variability was expressed by standard deviation (SD), time rate of BP variation (TR), average real variability (ARV) and coefficient of variation (CV) of systolic and diastolic BP for both 24-h, daytime and nighttime intervals. Statistical analysis was performed by means of bivariate correlations, simple and multiple linear regression analysis. Results: The study population consisted of 65 men (78%) and 18 women (22%). All diastolic BP variability indices did not correlated significantly with CCA-IMT. In contrast, 24-h systolic SD (r = 0.429, p < 0.001), TR (r = 0.576, p < 0.001), ARV (r = 0.537, p < 0.001) and CV (r = 0.309, p = 0.004) significantly correlated with CCA-IMT. The multivariate analysis revealed (ARV was excluded due to collinearity reasons) that 24-h systolic TR of BP variation was the only variable that was significantly and independently associated with CCA-IMT (B = 0.702, 95%CI 0.377–1.027, p < 0.001). The association remained significant after adjustment for baseline characteristics and risk factors. Conclusions: Systolic ambulatory BP variability indices such as SD, TR, ARV and CV are associated with CCA-IMT in CKD patients. The systolic TR of BP variation is better associated with CCA-IMT than the other indices in CKD patients.

Time Rate of Blood Pressure Variation Is Associated With Endothelial Function in Patients With Metabolic Syndrome.

The time rate of blood pressure (BP) variation indicates the speed of BP fluctuations. Previous studies have demonstrated that the time rate of BP variation was associated with target organ damage. However, the association between time rate of BP variation and endothelial function has not been evaluated.24-hour ambulatory blood pressure monitoring (ABPM) was performed in 61 patients with metabolic syndrome. Time rate of BP variation was calculated from BP recordings of ABPM. Endothelial function was assessed using reactive hyperemia-peripheral arterial tonometry index (RHI) by EndoPat2000. Multiple linear regression models were used to detect the association between time rate of BP variation and RHI.Among all the subjects (n = 61), the multiple linear regression models revealed that the daytime rate of systolic blood pressure (SBP) variation was independently associated with RHI (β = -0.334, P = 0.008). A 0.1 mmHg/minute increase in the daytime rate of SBP variation correlated with a decline of 0.20 in RHI. The same effect was also found in the subjects with eGFR ≥ 60 mL/ (minute*1.73 m(2)). A greater association was found in those who were not taking a statin, β-blocker, ACEI/ARB, or diuretic and those without diabetes compared with those with any antihypertensive medication or with diabetes. Other ambulatory blood pressure parameters and central hemodynamics were not found to be associated with RHI.Our findings have shown that the daytime rate of SBP variation was associated with endothelial function in patients with metabolic syndrome, independent of other BP parameters and central hemodynamics.

Brain edema formation is associated with the time rate of blood pressure variation in acute stroke patients

Both brain edema and increased blood pressure (BP) variability are associated with poor outcome after stroke. The aim of the present study was to evaluate a possible association between edema formation and a relatively new index of BP variability defined as time rate (TR) of BP variation. A total of 128 first-ever acute stroke patients underwent 24-h ambulatory BP monitoring within 24 h from onset of stroke. All patients were imaged with computed tomography scan on admission and after 5 days to determine the presence of brain edema. The TR of BP variation was defined as the first derivative of the BP values against time. Known risk factors and neurological severity on admission were documented. The 24-h TR of systolic BP variation was significantly higher (P<0.001) in stroke patients with brain edema (0.69±0.15 mmHg/min) compared with those without edema (0.57±0.12 mmHg/min). The multivariate logistic regression model showed that a 0.1 mmHg/min increase in the TR of 24-h systolic BP variation was associated with a 13.9% increased probability of the presence of brain edema (odds ratio=1.139, 95% confidence interval: 1.058-1.225, P<0.001), after adjusting for history of diabetes mellitus, hypercholesterolemia, type of stroke, neurological deficit, and 24-h systolic BP. Increased values of 24-h TR of systolic BP variation are associated independently with formation of edema in acute stroke patients.

Ambulatory blood pressure monitoring in acute stroke

Time rate of blood pressure (BP) variation is a measure of the speed of BP fluctuations derived from a computerized analysis of ambulatory BP monitoring. The aim of this study was to identify pathophysiological differences in the time rate of BP variation between stroke subtypes, on the basis of the Trial of Org 10172 in Acute Stroke Treatment criteria, in the acute phase and to examine the impact of time rate of BP variation on outcome at 1 year after stroke. A consecutive series of 109 first-ever stroke patients, who fulfilled our inclusion criteria, underwent 24 h ambulatory BP monitoring within 24 h after the onset of stroke. On the basis of the patients' Modified Rankin Scale score at 1 year after stroke, the study population was divided into two groups: patients with a positive (n=73) and those with a negative outcome (n=36). The 24-h rate of systolic BP variation is higher in patients with large artery atherosclerosis [0.692 mmHg/min; 95% confidence interval (CI) 0.627-0.757] compared with those with lacunar strokes (0.609 mmHg/min; 95% CI 0.579-0.640) or strokes of unknown etiology (0.586 mmHg/min; 95% CI 0.522-0.649). Moreover, patients with higher 24-h rates of systolic BP variation were more likely to have a negative outcome at 1 year (odds ratio 1.96; 95% CI 1.16-3.32). Moreover, each 0.1 mmHg/min increase in the 24-h rate of SBP variation was associated with a 1.96-fold increase in the odds of a negative outcome (95% CI 1.16-3.32). Time rate of BP variation shows significant differences between stroke subtypes in the acute phase of the event, and it is associated with outcome at 1 year. Lowering the time rate of BP variation, in the acute phase, might lead to better outcomes in patients who have had a cerebrovascular incident.

Time rate of blood pressure variation: a new factor associated with coronary atherosclerosis

Previous studies have demonstrated that the time rate of blood pressure (BP) variation was associated with early carotid atherosclerosis, independent of peripheral and central BP levels. We evaluated the association between the rate of BP variation, derived from ambulatory BP monitoring (ABPM) data analysis, and the severity and topography of coronary artery lesion in a cohort of normotensive patients with suspected coronary artery disease. ABPM and coronary angiography were performed in 162 normotensive patients with suspected coronary artery disease. The topography and severity of coronary artery lesions were assessed by Gensini score. The time rate of BP variation was defined as the first derivative of the BP values against time. Patients with coronary artery disease (n = 123) presented significantly (P = 0.005) higher daytime rate of systolic BP variation than control patients (n = 39). Multiple linear regression models revealed independent determinants of Gensini score in the following rank order: diabetes mellitus (β: +0.286, P < 0.001), daytime rate of systolic BP variation (β: +0.277, P < 0.001), daytime systolic BP (β: +0.216, P = 0.002), smoking (β: +0.178, P = 0.008) and hypercholesterolemia (β: +0.158, P = 0.020). A 0.1 mmHg/min increase in the daytime rate of systolic BP variation correlated with an increment of 4.935 in the Gensini score (95% CI 2.432-7.438). Steeper BP variations may produce a greater stress on the arterial wall and may have an additive role to vascular risk factors and BP parameters in the detection of the severity of coronary artery lesions in normotensive individuals with suspected coronary artery disease.

Time rate of blood pressure variation is superior to central hemodynamics as an associate of carotid intima–media thickness

The extent of target organ damage has been associated with both central hemodynamics and arterial stiffening, and the time rate of blood pressure (BP) changes in essential hypertension. However, the relative significance of these parameters has not been examined. We recruited 232 consecutive uncomplicated newly diagnosed hypertensive patients and 241 normotensive individuals. Twenty-four-hour ambulatory BP monitoring was performed in all individuals. The time rate of SBP variation was computed as the first derivative of the SBP values against time. Aortic central SBP and central DBP, central pulse pressure, central augmentation index and central augmentation pressure were assessed noninvasively by pulse wave analysis. Common carotid artery intima-media thickness was measured by high-resolution ultrasonography. Median 24-h time rate of BP changes was 0.571 +/- 0.114 mmHg/min. Traditional risk factors, office SBP, several ambulatory BP monitoring parameters (24-h SBP, 24-h pulse pressure, 24-h heart rate and BP dipping), 24-h time rate of BP changes, time rate of BP changes at different time intervals, and central SBP, central pulse pressure, central augmentation index and central augmentation pressure significantly correlated with intima-media thickness. Age, sex, BMI, 24-h time rate of BP changes, time rate of BP changes measured at 0100-0600 h and 24-h heart rate remained significant associates of intima-media thickness after adjustment for confounding factors. By multivariate stepwise linear regression, 24-h time rate of BP changes and time rate of BP changes at 0100-0600 h had incremental value over traditional risk factors, other ambulatory BP monitoring parameters and central hemodynamics. These findings indicate that time rate of BP variation is superior to central hemodynamics as an associate of carotid intima-media thickness in hypertensive and normotensive individuals.