Blood pressure variability within a single visit and all-cause mortality

BACKGROUND

Within-visit variability of repeated sequential readings of blood pressure (BP) is an important phenomenon that may affect precision of BP measurement and thus decision making concerning BP-related risk and hypertension management. However, limited data exist concerning predictive ability of within-visit BP variability for clinical outcomes. Therefore, we aimed to investigate the association between the variability of three repeated office BP measurements and the risk of all-cause mortality, independent of BP levels.

METHODS

Data collected through the National Health and Nutrition Examination Survey (NHANES) were analysed. NHANES is a program of studies designed to assess health and nutritional status of adults and children in the United States. A complete set of three sequential BP measurements, together with survival status, were available for 24969 individuals (age 46.8±;19.3 years, 49% males). Multivariable logistic regression models were used to determine the prognostic ability of the examined demographic, clinical, and haemodynamic indices.

RESULTS

Among various examined indices of variability of systolic (SBP) and diastolic (DBP) blood pressure measurements, the standard deviation of DBP (DBPSD) was the stronger independent predictor of mortality (odds ratio 1.064, 95% Confidence Interval: 1.011-1.12) after adjustment for age, sex, body mass index, smoking, SBP, heart rate, history of hypertension, diabetes mellitus, hypercholesterolaemia, and cardiovascular events.

CONCLUSION

Within-visit variability of three sequential office DBP readings may allow for the identification of high-risk patients better than mean SBP and DBP levels. The predictive value of within-visit BP variability and methods to improve its clinical application are worthy of further research.

Prevalence of childhood hypertension and hypertension phenotypes by weight status and waist circumference: the Healthy Growth Study

PURPOSE

The aim of the present study was to report for the first time the prevalence of hypertension and its phenotypes in obese children and in children with central obesity in a large sample of Greek children.

METHODS

A regionally representative sample of 2263 schoolchildren (50.3% boys) (9-13 years) having full data on blood pressure assessment, physical examination, anthropometric, and physical activity participated in a cross-sectional study in Greece.

RESULTS

Prevalence of stage 1 and 2 hypertension, of isolated systolic hypertension (ISH) and of combined systolic or diastolic hypertension, was significantly higher for obese children and children on the 3rd tertile of waist circumference in the total sample, as well as in each gender separately. ISH was the most prevalent phenotype reaching 24.3% in obese children and 17.5% in children on the highest tertile of waist circumference. Obese children and children on the highest tertile of waist circumference had 6.31 times and 3.94 times, respectively, higher likelihood to have abnormal systolic or diastolic blood pressure (SBP or DBP) than their normal-weight counterparts.

CONCLUSIONS

Prevalence of hypertension and especially ISH in obese children and in children with central obesity in Greece are among the highest reported in Europe. Future public health initiatives should aim to prevent or tackle several underlying factors related to childhood hypertension, focusing primarily on children with excess body weight.

Clinical interaction between diabetes duration and aortic stiffness in type 2 diabetes mellitus

Diabetes complications increase with disease duration. No study was performed on the relationship between aortic stiffness and diabetes duration, taking into account the respective influence of such factors on macro- and microcirculation. In total, 618 subjects with type 2 diabetes (259 men) attending the Department of Internal Medicine of Tizi Ouzou Hospital (Algeria) were studied in collaboration with Hotel-Dieu Hospital (Paris, France). Brachial blood pressure (BP), anthropometric, clinical and biological data were evaluated. Aortic stiffness was estimated by carotid-femoral pulse wave velocity (PWV). From lower to higher tertile of diabetes duration, age, BP and PWV (10.1±2.7 to 12.3±2.8 m s^-1) increased, while diabetes control and renal function worsened (all P<0.01). Diabetes duration was independently associated with PWV (R²=0.035, P<0.0001), even after adjustment for age, BP, heart rate, cardiovascular events and metabolic syndrome. Diabetes duration was significantly correlated to the prevalence of microalbuminuria (OR (95% CL) 1.3 (1.06-1.63), P=0.01), independently of age, sex, BP and renal function. Increased aortic stiffness was independently associated with the prevalence of cardiovascular events (P<0.001), reaching its maximal value above the first 2 years of diabetes duration. In conclusion, diabetes duration is an independent determinant of aortic stiffness in subjects with type 2 diabetes, representing about 4% of PWV variability. Diabetes duration is associated with microvascular complications independently of renal function, and with macrovascular complications through the presence of increased aortic stiffness.

Association of consumption of dairy products and meat with retinal vessel calibers in subjects at increased cardiovascular risk

BACKGROUND AND AIMS

Association of dairy products and meat consumption with macrocirculation is previously described, but such association with microcirculation is poorly investigated. We aimed to test the hypothesis that the consumption of high- and low-fat dairy products as well as red, white, and processed meat is associated with retinal vessel calibers in adults at an increased risk of cardiovascular disease (CVD).

METHODS AND RESULTS

In consecutive subjects (n = 181, age: 51.3 ± 12.4 years, 51.4% women) without CVD and diabetes mellitus but with increased CVD risk, we obtained digital left and right retinal images. These images were assessed with validated software to determine central retinal arteriolar and venular equivalents and the arteriolar to venular ratio (CRAE, CRVE, and AVR, respectively). The consumption of dairy products and meat was assessed through 24-h recalls in all volunteers. After adjustment for potential confounders, the following findings were obtained: (i) low-fat milk and yogurt were positively associated with CRAE (b=0.145, p=0.031 left; b=0.141, p=0.038 right) and inversely associated with CRVE (b=-0.155, p=0.026 left; b=-0.146, p=0.041 right); (ii) low-fat cheese was positively associated with CRAE (b=0.164, p=0.011 left and b=0.155, p=0.017 right); and (iii) red meat was inversely associated with CRAE (b=-0.143, p=0.032 left; b=-0.114, p=0.050 right). High-fat milk, yogurt, and cheese or white and processed meat were not found to be associated with retinal vessel calibers.

CONCLUSIONS

High consumption of low-fat milk, yogurt, and cheese and low consumption of red meat could be beneficial for retinal microvascular health. Prospective studies are needed to verify these findings.

Association of left ventricular diastolic dysfunction with 24-h aortic ambulatory blood pressure: the SAFAR study

Aortic blood pressure (BP) and 24-h ambulatory BP are both better associated with target organ damage than office brachial BP. However, it remains unclear whether a combination of these two techniques would be the optimal methodology to evaluate patients' BP in terms of left ventricular diastolic dysfunction (LVDD) prevention. In 230 participants, office brachial and aortic BPs were measured by a validated BP monitor and a tonometry-based device, respectively. 24-h ambulatory brachial and aortic BPs were measured by a validated ambulatory BP monitor (Mobil-O-Graph, Germany). Systematic assessment of patients' LVDD was performed. After adjustment for age, gender, hypertension and antihypertensive treatment, septum and lateral E/Ea were significantly associated with office aortic systolic BP (SBP) and pulse pressure (PP) and 24-h brachial and aortic SBP and PP (P ⩽ 0.04), but not with office brachial BP (P ⩾ 0.09). Similarly, 1 standard deviation in SBP was significantly associated with 97.8 ± 20.9, 86.4 ± 22.9, 74.1 ± 23.3 and 51.3 ± 22.6 in septum E/Ea and 68.6 ± 2 0.1, 54.2 ± 21.9, 37.9 ± 22.4 and 23.1 ± 21.4 in lateral E/Ea, for office and 24-h aortic and brachial SBP, respectively. In qualitative analysis, except for office brachial BP, office aortic and 24-h brachial and aortic BPs were all significantly associated with LVDD (P ⩽ 0.03), with the highest odds ratio in 24-h aortic SBP. Furthermore, aortic BP, no matter in the office or 24-h ambulatory setting, showed the largest area under receiver operating characteristic curves (P ⩽ 0.02). In conclusion, 24-h aortic BP is superior to other BPs in the association with LVDD.

A pilot study of endothelial dysfunction and aortic stiffness after interleukin-6 receptor inhibition in rheumatoid arthritis

Interleukin (IL)-6 is a pleiotropic proinflammatory cytokine involved in the pathogenesis of both atherosclerosis and rheumatoid arthritis. The role of the IL-6/IL-6 receptor pathway in the documented acceleration of atherosclerosis in rheumatoid arthritis has not been examined. In a non-randomized prospective pilot study we asked whether endothelial dysfunction, defined as impaired flow mediated dilatation (FMD), and aortic stiffness, assessed by pulse wave velocity (PWV) improve after 3 and 6 monthly therapeutic infusions of the anti-IL-6 receptor antibody tocilizumab for active rheumatoid arthritis. We found that FMD increased from 3.3 ± 0.8 to 4.4 ± 1.2 to 5.2 ± 1.9% (p = 0.003), whereas PWV decreased from 8.2 ± 1.2 to 7.7 ± 1.3 to 7.0 ± 1.0m/s (p < 0.001). Whether these beneficial arterial changes are direct effects of the IL-6/IL-6 receptor pathway inhibition, maintained over time and translate into better clinical outcome warrants further studies.

The effect of heart rate on wave reflections may be determined by the level of aortic stiffness: clinical and technical implications

BACKGROUND

Augmentation Index (AIx) is related to cardiovascular diseases, risk, and mortality. AIx is associated with heart rate but the effect of aortic stiffness on this relationship has not been studied. The purpose of our study was to investigate the relationship between AIx and heart rate at different aortic stiffness levels.

METHODS

The study consisted of 425 normotensive and untreated hypertensive subjects. Wave reflections and pulse-wave velocity (PWV) were determined by the Sphygmocor and the Complior systems, respectively.

RESULTS

AIx was independently associated with heart rate, age, gender, height, mean blood pressure (BP) and the effective reflection site distance (ERD). The population was divided into three groups of those with different PWV levels (tertiles). The regression lines for AIx with heart rate differed significantly between the 3rd and the other two tertiles of PWV (P = 0.039 for slopes and P = 0.002 for intercepts). This difference remained significant even after adjustment for age, gender, height, mean BP, and distance of wave reflections.

CONCLUSIONS

A significantly stronger correlation of AIx with heart rate was observed in subjects with higher levels of aortic stiffness as compared to those with lower levels; namely, the same increase in the heart rate between subjects, induced a greater decrease in the AIx at higher compared to lower PWV levels. The correction of AIx for heart rate should be reconsidered based on the aortic stiffness level. This finding has implications for interventional studies that aim to improve central hemodynamics but simultaneously affect heart rate. Further studies that show acute modifications of heart rate at different arterial stiffness levels are required to support these findings.

Cardiovascular risk factors in adult patients with multisystem Langerhans-cell histiocytosis: evidence of glucose metabolism abnormalities

BACKGROUND

Langerhans-cell histiocytosis (LCH) is a rare disease with features of chronic inflammation and it may also induce hypopituitarism, conditions associated with an increased risk of cardiovascular diseases.

AIM

Cardiovascular and metabolic risk profile investigation in multisystem LCH patients with and without anterior pituitary deficiency.

DESIGN

Prospective, observational study.

METHODS

Fourteen adult patients with LCH, 7 with and 7 without anterior pituitary deficiency, and 42 controls matched for age, body mass index (BMI) and smoking. Cardiovascular risk factors were estimated in all subjects: glucose and lipid profile, mathematical indices of insulin resistance (IR), blood pressure, structural arterial and functional endothelial properties (intima-media thickness, brachial artery flow-mediated dilatation). Cardiovascular risk factors were estimated in the three groups studied; the effect of disease activity and/or treatment was also determined in patients with LCH.

RESULTS

Ten patients had diabetes insipidus, and 7 anterior pituitary hormone deficiencies: 8 patients had active disease and 11 had received systemic treatment. No difference was observed between the study groups in vascular parameters, in lipid profile or in blood pressure. However, the insulin resistance index GIR was decreased in patients with LCH without anterior pituitary deficiency compared to controls (P = 0.033). Three patients had impaired glucose tolerance and one diabetes mellitus type 2. These patients were older and had active disease; there was no association with hypopituitarism and/or previous treatment.

CONCLUSION

Adults patients with LCH have abnormalities of glucose metabolism that tend to occur in patients with active disease, and may be a consequence of the pro-inflammatory state.

Structural and functional arterial properties in patients with obstructive sleep apnoea syndrome and cardiovascular comorbidities

The increased severity of obstructive sleep apnoea syndrome (OSAS) is associated with a parallel increase in the incidence of cardiovascular events. Whether the increased severity of OSAS is in fact associated with impaired arterial properties has never been thoroughly studied. In patients with OSAS who carry a high burden of cardiovascular risk factors, we investigated whether the severity of OSAS is associated with deterioration in the arterial properties, independent of classical cardiovascular risk factors. In 74 consecutive patients with OSAS, we non-invasively assessed, by means of tonometry and high-resolution ultrasound: carotid intima-media thickness (IMT), carotid diameter and plaques, carotid-femoral pulse wave velocity (PWV), central augmentation index (AI) and central blood pressures. The respiratory disturbance index was an independent predictor of IMT and PWV but not of carotid plaques, carotid diameter, AI or central blood pressures. Several parameters of nocturnal hypoxaemia were independently correlated with carotid IMT and PWV. In conclusion, arterial stiffening and thickening are modulated by the severity of OSAS, independently from age and cardiovascular risk factors.

Acute effects of renin-angiotensin system blockade on arterial function in hypertensive patients

The acute effects of the renin-angiotensin system (RAS) blockers may be important in some clinical settings. To assess the acute impact of such drugs on arterial function, we studied the effects of captopril 25 mg, quinapril 20 mg and telmisartan 80 mg on 100 hypertensive patients, according to a randomized, double-blind, placebo-controlled study. Central (aortic) blood pressure (BP) and augmentation index (AIx, a measure of wave reflections), as well as flow-mediated dilatation (FMD) of the brachial artery and forearm blood flow (FBF) (measures of conduit and resistance artery endothelial function, respectively), were evaluated before and 2 h after oral drug administration. Compared to placebo, captopril and quinapril decreased central systolic (by 7.5 mm Hg, P<0.05 and by 12.3 mm Hg, P<0.001) and diastolic BP (by 4.9 mm Hg, P<0.01 and by 8.4 mm Hg, P<0.001), whereas telmisartan had no significant effect (P=NS). Additionally, AIx was reduced after quinapril (absolute decrease of 7.2%, P<0.01) and marginally after captopril (decrease of 4.7%, P=0.07). Only quinapril led to a beneficial change of FMD (absolute increase of 2.7%, P<0.001). No treatment was related to significant changes of peak hyperaemic or 3-min hyperaemic FBF. In adjusted analyses, all the favourable alterations induced by quinapril were independent of potential confounding haemodynamic factors. Our data show that acute RAS inhibition with quinapril (20 mg) may be more beneficial in terms of arterial function and central haemodynamics compared to captopril (25 mg) or telmisartan (80 mg). Further studies are needed to investigate whether these acute arterial effects of quinapril are clinically significant.

The combined effect of augmentation index and carotid intima-media thickness on cardiovascular risk in young and middle-aged men without cardiovascular disease

Carotid artery intima-media thickness (IMT) has been used as a surrogate marker of atherosclerosis and is related to cardiovascular risk. Indices of arterial stiffness are also associated with cardiovascular risk and atherosclerosis. The aim of this study was to assess the prognostic value of the combination of surrogate markers of cardiovascular disease measured non-invasively in subjects without cardiovascular disease. In this cross-sectional study, 81 young and middle aged males (39.2+/-6.3 years) without evidence of overt cardiovascular disease or diabetes mellitus were enrolled. High-resolution B-mode ultrasonography and pulse wave analysis were used to measure carotid artery IMT and augmentation index (AI), a measure of arterial stiffness. Framingham risk score (FRS) was used as an estimate of the risk for development of cardiovascular disease. Regional differences were observed in the carotid arteries' IMT regarding their relationship with FRS: combined (average from all sites) IMT and IMT in the carotid bulb (CB), but not in the common (CC) and internal carotid artery (IC), and AI showed significant increases of FRS by their tertiles. However, subjects with both AI and IMT at any site in the highest tertile (AI>15%, CC>0.65 mm, CB>0.8 mm, IC>0.65 mm) had an increased FRS compared to subjects with one or none of these parameters in the highest tertile. In conclusion, young and middle-aged men without overt cardiovascular disease with both high IMT and AI are in high cardiovascular risk, as assessed by FRS. Epidemiological studies are needed to further validate this combination.

Heart rate effect on hemodynamics during mechanical assistance by the intra-aortic balloon pump

Heart rate (HR) has been characterized as an important cardiovascular parameter that affects acute hemodynamic performance of intra-aortic balloon counterpulsation (IABC). However, the effect of HR on hemodynamics during mechanical assistance by the IABC has neither been clarified nor quantified. We sought to evaluate the relationship between IABC and HR and also to examine whether there is a range of HR with optimum hemodynamic response to IABC.

METHODS

20 patients (14 males--6 females, mean age 64.4 +/- 11.4 years) with post-infarction cardiogenic shock undergoing IABC treatment were evaluated. Hemodynamics were recorded for each patient once per day during the assistance period; 131 measurements were taken and thus a wide range of heart rates was obtained (64-141 bpm). The following changes in aortic pressures were used to evaluate acute IABC performance on: a) the maximal increase of diastolic aortic pressure induced by IABC and b) the reduction in systolic and end-diastolic aortic pressure.

RESULTS

Non-linear regression analysis and analysis of variance revealed that a significant correlation exists between IABC performance indices and heart rate. At HR<80 bpm, IABC performance tended to be reduced, whereas the increase in HR above 110 bpm resulted in a significant reduction of all IABC performance indices. In contrast, IABC operating at 80-110 bpm resulted in optimum hemodynamic performance. In conclusion, the effect of heart rate on IABC performance is non-linear indicating that IABC may be more effective when operating within 80-110 bpm.