Influence of sex on the relation between heart rate and aortic stiffness

BACKGROUND: Heart rate and aortic pulse wave velocity (PWV) are both cardiovascular risk factors. The aim of this study was to evaluate the influence of sex on the heart rate-PWV relationship in two populations of normotensive and hypertensive men and women. PATIENTS AND METHODS: In a first study, steady-state data describing the heart rate-PWV relationship were determined in 558 normotensive men, 308 normotensive women, 323 hypertensive men and 93 hypertensive women. In a second study, the changes in blood pressure and PWV under atrial pacing at 60, 80 and 100 beats/min were investigated in 15 men and 15 women who were either normotensive or hypertensive. RESULTS: In women in study 1, 26.8% of PWV variance in normotensive patients and 15.4% of PWV variance in hypertensive patients was explained by a multiple regression including only age and systolic blood pressure as covariates. In men in study 1, 27% of PWV variance in normotensive patients and 28.5% of PWV variance in hypertensive patients was explained by a multiple regression including age, systolic blood pressure, weight, and also heart rate, as covariates. In study 2, atrial pacing in the overall population tended to decrease mean blood pressure (P = 0.05) and increase pulse pressure (P = 0.003), with no substantial change in PWV. However, when heart rate increased, PWV tended to decrease in women and to increase in men (interaction: P = 0.07).CONCLUSION Accelerated heart rate influences PWV in both normotensive and hypertensive men and, through this mechanism, could influence cardiovascular risk. However, heart rate does not influence PWV in women.     

Why cardiovascular mortality is higher in treated hypertensives versus subjects of the same age,in the general population

OBJECTIVE: The aim of the present study was to assess whether increased cardiovascular mortality in treated hypertensives could be explained by high blood pressure levels, or by the presence of associated risk factors and/or associated diseases. DESIGN: The study sample consisted of 8893 treated hypertensive men and women from the Investigations Préventives et Cliniques cohort, and 25880 gender-matched and age-matched untreated subjects from the same cohort. Vital status was obtained for an 8-12 year period. RESULTS: Treated hypertensive subjects had higher systolic blood pressure (SBP) (+ 15 mmHg) and higher diastolic blood pressure (+ 9 mmHg), and a higher prevalence of associated risk factors and diseases. Treated hypertensives compared with untreated subjects presented a two-fold increase in the risk ratio (RR) for cardiovascular mortality [RR, 1.96; 95% confidence interval (CI), 1.74-2.22] and coronary mortality (RR, 1.99; 95% CI, 1.63-2.44). Adjustment for unmodifiable risk factors decreased the excess cardiovascular risk observed in treated subjects only slightly: RR, 1.77; 95% CI, 1.56-2.00 for cardiovascular mortality; and RR, 1.76; 95% CI, 1.44-2.16 for coronary mortality. After additional adjustment for modifiable associated risk factors, the increased mortality in treated subjects persisted: RR, 1.52; 95% CI, 1.33-1.74 for cardiovascular mortality; and RR, 1.49; 95% CI, 1.19-1.86 for coronary mortality. Only after additional adjustment for SBP were cardiovascular mortality and coronary mortality similar in the two groups of subjects: RR, 1.06; 95% CI, 0.92-1.23; and RR, 1.06; 95% CI, 0.85-1.35, respectively. CONCLUSIONS: The increased cardiovascular mortality in treated hypertensive subjects as compared with untreated subjects is mainly due to high SBP levels under treatment. This result suggests that the excess risk found in treated hypertensives may be drastically reduced if SBP were brought under control.     

Pathophysiology of Hypertension in the Elderly

Systolic hypertension is the most common type of hypertension in the elderly and a major modifiable cardiovascular risk factor. Systolic hypertension is associated with a wide pulse pressure resulting largely from excessive large artery stiffness. Arterial stiffness increases with age independently of mean blood pressure or the presence of other risk factors. In this review, the authors discuss the effects of age and blood pressure on arterial stiffness, the physiology of arterial compliance, and the anatomic changes of large arteries with aging. In most studies reported in the literature, elderly populations are relatively small. The role of both age and gender on arterial stiffness and wave reflection has been poorly investigated, particularly in subjects over 70 years. In this elderly population, further research is needed concerning the pathophysiology, epidemiology, and pharmacology of hypertension.     

Gene polymorphisms of the renin-angiotensin system and age-related changes in systolic and diastolic blood pressure in subjects with hypertension

BACKGROUND: Few studies have examined to what extent genes might modulate the changes of systolic and diastolic blood pressure (BP) with age although, in older populations, systolic BP and diastolic BP vary with age in opposite directions. METHODS: This study involved 205 men and 99 women with either systolic-diastolic or isolated systolic hypertension. Age was > 50 years. Using polymerase chain reaction, four gene polymorphisms related to the renin-angiotensin system were independently investigated in men and women. Adjustments to cardiovascular and renal risk factors as well to the sodium/potassium extracellular space ratio were performed. RESULTS: Regarding the angiotensin-converting enzyme (ACE) gene polymorphism, in men > 50 years of age, the slope (mm Hg per unit of age) of the age-diastolic BP (and not age-systolic BP) relationships significantly (P = .0092) differed between genotypes: - 0.79 +/- 0.15 (P < .0001) for the DD genotype, -0.53 +/- 0.10 for the ID genotype (P < .0001), and -0.23 +/- 0.11 for II genotypes (P = NS). Such findings were not observed in the female population in which the age-diastolic BP curves were substantially flatter than in men. No comparable results were observed for gene polymorphisms related either to angiotensinogen or to angiotensin II type 1 receptor. CONCLUSIONS: In men > 50 years of age, the ACE gene polymorphism modulates the physiologic age-induced reduction of diastolic BP. The D allele might contribute to enhance this reduction, a finding that needs confirmation using prospective studies.     

Comparative study of methodologies for pulse wave velocity estimation

Arterial stiffness, estimated by pulse wave velocity (PWV), is an independent predictor of cardiovascular mortality and morbidity. However, the clinical applicability of these measurements and the elaboration of reference PWV values are difficult due to differences between the various devices used. In a population of 50 subjects aged 20-84 years, we compared PWV measurements with three frequently used devices: the Complior and the PulsePen, both of which determine aortic PWV as the delay between carotid and femoral pressure wave and the PulseTrace, which estimates the Stiffness Index (SI) by analyzing photoplethysmographic waves acquired on the fingertip. PWV was measured twice by each device. Coefficient of variation of PWV was 12.3, 12.4 and 14.5% for PulsePen, Complior and PulseTrace, respectively. These measurements were compared with the reference method, that is, a simultaneous acquisition of pressure waves using two tonometers. High correlation coefficients with the reference method were observed for PulsePen (r = 0.99) and Complior (r = 0.83), whereas for PulseTrace correlation with the reference method was much lower (r = 0.55). Upon Bland-Altman analysis, mean differences of values +/- 2s.d. versus the reference method were -0.15 +/- 0.62 m/s, 2.09 +/- 2.68 m/s and -1.12 +/- 4.92 m/s, for PulsePen, Complior and Pulse-Trace, respectively. This study confirms the reliability of Complior and PulsePen devices in estimating PWV, while the SI determined by the PulseTrace device was found to be inappropriate as a surrogate of PWV. The present results indicate the urgent need for evaluation and comparison of the different devices to standardize PWV measurements and establish reference values.     

Effect of a short‐term intermittent exercise‐training programme on the pulse wave velocity and arterial pressure: a prospective study among 71 healthy older subjects

Aims of the study: Stiffening of large arteries has been associated with increased cardiovascular outcomes among older subjects. Endurance exercises might attenuate artery stiffness, but little is known about the effects of intermittent training programme. We evaluate the effect of a short Intermittent Work Exercise Training Program (IWEP) on arterial stiffness estimated by the measure of the pulse wave velocity (PWV). Methods and subjects: Seventy‐one healthy volunteers (mean age: 64.6 years) free of symptomatic cardiac and pulmonary disease performed a 9‐week IWEP that consisted of a 30‐min cycling twice a week over a 9‐week period. Each session involved six 5‐min bouts of exercise, each of the latter separated into 4‐min cycling at the first ventilatory threshold alternated with 1‐min cycling at 90% of the pretraining maximal tolerated power. Before and after the IWEP, the following measurements were made: carotid–radial PWV and carotid–femoral PWV with a tonometer and systolic and diastolic blood pressure. Results: Training resulted in a non‐significant decrease of the carotid–radial PWV, a significant decrease of the carotid–femoral PWV from 10.2 to 9.6 m/s (p < 0.001) (that was no longer significant after adjustment for mean arterial pressure) and a significant decrease in both systolic and diastolic blood pressure, respectively, from 129.6 ± 14.9 mmHg to 120.1 ± 14.1 mmHg (p < 0.001) and from 77.2 ± 8.8 mmHg to 71.4 ± 10.1 mmHg (p < 0.001). Conclusion: The present results support the idea that a short‐term intermittent aerobic exercise programme may be an effective lifestyle intervention for reducing rapidly blood pressure and probably central arterial stiffness among older healthy subjects.     

Moderately increased alcohol consumption is associated with higher pressure wave reflections and blood pressure in men

Background and aimsIncreased alcohol consumption has been associated with CVD risk. Subclinical arterial damage (SAD) precedes the onset of cardiovascular disease (CVD), and allows early identification and study of the pathophysiology of CVD. Reliable, noninvasive vascular biomarkers are available for the early detection of SAD and reclassification of CVD risk. To investigate the association of alcohol consumption with multiple SAD biomarkers and central hemodynamics in a large sample of Greek adults with CVD risk factors.Methods and resultsThis cross-sectional study was conducted with 938 participants (43.5% men) and collected data on SAD biomarkers, central hemodynamics, and dietary intake. Multiple linear regression analysis was performed according to sex after adjusting for several confounders. In men, alcohol consumption of 20–30 g/d was positively associated with mean, diastolic, and peripheral systolic blood pressure (BP). The consumption of >30 g/d was positively associated with the augmentation index. In women, no statistically significant associations were found between alcohol consumption and BP or SAD indices. No statistically significant associations were found between alcohol consumption and arterial compliance or distensibility in both sexes.ConclusionIn men even a small deviation from the current recommendation for alcohol consumption is associated with both higher BP indices and pressure wave reflections. The absence of association in women might be due to very low alcohol intake, even in the high consumption group. More studies are needed to verify our findings and establish the above associations in each sex.     

Norepinephrine applied in the paraventricular hypothalamic nucleus stimulates vasopressin release

The present experiments were designed to investigate the effect of norepinephrine (NE) applied directly in the area of the paraventricular nucleus (PVN) of the hypothalamus on arginine-vasopressin (AVP) release and blood pressure. A microinjection of 0.4 micrograms NE in the PNV produced a plasma AVP level of 26.3 +/- 5.3 pg/ml compared to 5.3 +/- 0.6 pg/ml in controls receiving dextrose (P less than 0.001). This rise was associated with blood pressure elevations varying between 10 and 13 mm Hg, lasting for about 5 min. Systemic injection of an antivasopressor AVP antagonist reversed or prevented the blood pressure rise induced by NE microinjection. The data suggest that locally applied NE in vasopressinergic neurons of the hypothalamus stimulates the release of AVP and induces an AVP-dependent rise in blood pressure.     

Massive prolapse of the urethral mucosa following periurethral injection of calcium hydroxylapatite for stress urinary incontinence

The injection of bulking agents into the urethral submucosa is designed to create artificial urethral cushions that can improve urethral coaptation and hence restore continence. Ideally, a urethral bulking agent should be non-immunogenic and biocompatible, leading to minimal inflammatory and fibrotic response. The authors present a case report of a granulomatous reaction leading to urethral prolapse, 3 months after the transurethral injection of calcium hydroxylapatite. To our knowledge, this is the first granulomatous reaction described after calcium hydroxylapatite injection.