András Tislér

High prevalence of unrecognized sleep apnoea in drug-resistant hypertension

Objectives To determine the prevalence of obstructive sleep apnoea (OSA) in adult patients with drug-resistant hypertension, a common problem in a tertiary care facility. Design Cross-sectional study. Setting University hypertension clinic. Patients and methods Adults with drug-resistant hypertension, defined as a clinic blood pressure of ⩾ 140/90 mmHg, while taking a sensible combination of three or more antihypertensive drugs, titrated to maximally recommended doses. Each of the 41 participants completed an overnight polysomnographic study and all but two had a 24 h ambulatory blood pressure measurement. Results Prevalence of OSA, defined as an apnoea-hypopnoea index of ⩾ 10 obstructive events per hour of sleep, was 83% in the 24 men and 17 women studied. Patients were generally late middle-aged (57.2 ± 1.6 years, mean ± SE), predominantly white (85%), obese (body mass index, 34.0 ± 0.9 kg/m2) and taking a mean of 3.6 ± 0.1 different antihypertensive medications daily. OSA was more prevalent in men than in women (96 versus 65%, P = 0.014) and more severe (mean apnoea–hypopnoea index of 32.2 ± 4.5 versus 14.0 ± 3.1 events/h, P = 0.004). There was no gender difference in body mass index or age. Women with OSA were significantly older and had a higher systolic blood pressure, lower diastolic blood pressure, wider pulse pressure and slower heart rate than women without OSA. Conclusions The extraordinarily high prevalence of OSA in these patients supports its potential role in the pathogenesis of drug-resistant hypertension, and justifies the undertaking of a randomized controlled trial to corroborate this hypothesis.

European Society of Hypertension guidelines for blood pressure monitoring at home: a summary report of the Second International Consensus Conference on Home Blood Pressure Monitoring.

This document summarizes the available evidence and provides recommendations on the use of home blood pressure monitoring in clinical practice and in research. It updates the previous recommendations on the same topic issued in year 2000. The main topics addressed include the methodology of home blood pressure monitoring, its diagnostic and therapeutic thresholds, its clinical applications in hypertension, with specific reference to special populations, and its applications in research. The final section deals with the problems related to the implementation of these recommendations in clinical practice.

European Society of Hypertension practice guidelines for home blood pressure monitoring.

Self-monitoring of blood pressure by patients at home (home blood pressure monitoring (HBPM)) is being increasingly used in many countries and is well accepted by hypertensive patients. Current hypertension guidelines have endorsed the use of HBPM in clinical practice as a useful adjunct to conventional office measurements. Recently, a detailed consensus document on HBPM was published by the European Society of Hypertension Working Group on Blood Pressure Monitoring. However, in daily practice, briefer documents summarizing the essential recommendations are needed. It is also accepted that the successful implementation of clinical guidelines in routine patient care is dependent on their acceptance by involvement of practising physicians. The present document, which provides concise and updated guidelines on the use of HBPM for practising physicians, was therefore prepared by including the comments and feedback of general practitioners.

Refractory hypertension and sleep apnoea: effect of CPAP on blood pressure and baroreflex

This study was undertaken to determine whether abolition of obstructive sleep apnoea (OSA) by continuous positive airway pressure (CPAP) could reduce blood pressure (BP) in patients with refractory hypertension. In 11 refractory hypertensive patients with OSA, the acute effects of CPAP on nocturnal BP were studied during sleep and its longer term effects on 24-h ambulatory BP after 2 months. During a single nights application, CPAP abolished OSA and reduced systolic BP in stage 2 sleep from 138.3±6.8 to 126.0±6.3 mmHg. There was also a trend towards a reduction in average diastolic BP (from 77.7±4.5 to 72.9±4.5). CPAP usage for 2 months was accompanied by an 11.0±4.4 mmHg reduction in 24-h systolic BP. In addition, both the nocturnal and daytime components of systolic BP fell significantly by 14.4±4.4 and 9.3±3.9 mmHg, respectively. Diastolic BP was reduced significantly at night by 7.8±3.0 mmHg. In patients with refractory hypertension, acute abolition of obstructive sleep apnoea by continuous positive airway pressure reduces nocturnal blood pressure. These data also suggest that continuous positive airway pressure may reduce nocturnal and daytime systolic blood pressure chronically. Randomised trials are needed to confirm the latter results.

Effect of Home Blood Pressure Telemonitoring With Self-Care Support on Uncontrolled Systolic Hypertension in Diabetics

Lowering blood pressure reduces cardiovascular risk, yet hypertension is poorly controlled in diabetic patients. In a pilot study we demonstrated that a home blood pressure telemonitoring system, which provided self-care messages on the smartphone of hypertensive diabetic patients immediately after each reading, improved blood pressure control. Messages were based on care paths defined by running averages of transmitted readings. The present study tests the systems effectiveness in a randomized, controlled trial in diabetic patients with uncontrolled systolic hypertension. Of 244 subjects screened for eligibility, 110 (45%) were randomly allocated to the intervention (n=55) or control (n=55) group, and 105 (95.5%) completed the 1-year outcome visit. In the intention-to-treat analysis, mean daytime ambulatory systolic blood pressure, the primary end point, decreased significantly only in the intervention group by 9.1±15.6 mmHg (SD; P<0.0001), and the mean between-group difference was 7.1±2.3 mmHg (SE; P<0.005). Furthermore, 51% of intervention subjects achieved the guideline recommended target of <130/80 mmHg compared with 31% of control subjects (P<0.05). These improvements were obtained without the use of more or different antihypertensive medications or additional clinic visits to physicians. Providing self-care support did not affect anxiety but worsened depression on the Hospital Anxiety and Depression Scale (baseline, 4.1±3.76; exit, 5.2±4.30; P=0.014). This study demonstrated that home blood pressure telemonitoring combined with automated self-care support reduced the blood pressure of diabetic patients with uncontrolled systolic hypertension and improved hypertension control. Home blood pressure monitoring alone had no effect on blood pressure. Promoting patient self-care may have negative psychological effects.

Attitudes of primary care physicians and their patients about home blood pressure monitoring in Ontario

Objective Guidelines recommend home blood pressure monitoring (HBPM) to improve blood pressure control, but the attitudes of primary care physicians and their hypertensive patients towards its use are not known. Methods A 28-item self-administered survey about home blood pressure monitoring was mailed to a random sample of 1418 primary care physicians in Ontario and 765 (55%) were returned. Of the 478 physicians treating hypertension, 299 agreed to give surveys to their hypertensive patients. We received 149 patient surveys. Results The majority of primary care physicians (63%) often or almost always encouraged their hypertensive patients to monitor their own blood pressure at home. Only 13%, however, preferred home blood pressure monitoring to office or ambulatory readings for diagnostic purposes and 19%, to guide therapy. Physicians had concerns about patients becoming preoccupied with home monitoring (70%) and the accuracy of home devices (65%). Most patients (78%) had a device at home, and 84% indicated that their doctor encouraged them to measure blood pressure. Yet, 80% received no advice from their physician on the type of device to purchase, only 8% had specific training on proper measurement technique, 68% did not regularly take the results to the doctor and 39% did nothing specific about alarming readings. Conclusions Primary care physicians prefer office or ambulatory to home readings to make diagnostic and therapeutic decisions. While home monitoring is popular among patients, its clinical usefulness is undermined by the lack of reliable purchasing information, standard measurement protocols, proper training on measurement technique and specific instructions on handling and interpreting results.

Comparison of Dialysis and Clinical Characteristics of Patients with Frequent and Occasional Hemodialysis-Associated Hypotension

Background: Symptomatic dialysis hypotension (DH) continues to be a common problem. By comparing patients prone and resistant to DH, several dialysis session and patient related characteristics have been identified that confer susceptibility to DH. Less is known, however, about the comparison of patients with frequent and only occasional DH. The aim of the study was to compare clinical and dialysis-session- (complicated by hypotension) related data between those with frequent (fDH) and those with occasional dialysis hypotension (oDH). Methods: Nine hundred and fifty-eight patients at 11 dialysis units were followed for 10 months and characteristics of patients with fDH (≧10 hypotensive events necessitating medical intervention) (n = 96) were compared to that of patients with oDH (1 or 2 events/10 months) (n = 130). Significant and independent predictors of fDH were obtained by multivariate logistic regression. Results: Significant differences between fDH vs. oDH patients were older age (64.4 vs. 56.9 years, p < 0.001), more females (66 vs. 46%, p < 0.005) in fDH. More fDH patients had diabetes (27 vs. 15%, p < 0.05) and less had glomerulonephritis (15 vs. 35%, p < 0.001) as the cause for ESRD. Coronary artery disease (68 vs. 50%, p < 0.01) and long-acting nitrate treatment (51 vs. 30%, p < 0.001) was more frequent while treatment with ACEI (33 vs. 48%, p < 0.05) or Ca-channel blockers (40 vs. 53%, p < 0.05) were less frequent in patients with fDH. Patients with fDH had higher serum phosphorus levels (1.99 vs. 1.79 mmol, p < 0.005). Dialysis session related data were similar but the hypotensive episode occurred earlier during dialysis in fDH (136 vs. 156 min, p < 0.01). In multivariate analysis, significant independent predictors of fDH were older age (OR = 1.04 [1.02–1.07]), lack of glomerulonephritis as renal diagnosis (2.63 [1.18–5.87]), high phosphorus levels (5.0 [2.45–10.0]), lack of use of Ca-channel blockers (2.09 [1.12–3.91]), and the use of nitrates (2.38 [1.24–4.55]). Conclusion: Features of the dialysis sessions complicated by DH seem to be similar between patients with fDH and oDH, while patient characteristics such as older age, renal diagnosis other than glomerulonephritis, higher serum phosphorus levels, use of nitrates, and lack of use of calcium channel blockers are significantly and independently associated with fDH.

Serum osteoprotegerin level, carotid-femoral pulse wave velocity and cardiovascular survival in haemodialysis patients

BACKGROUND Osteoprotegerin (OPG) is a marker and regulator of arterial calcification, and it is related to cardiovascular survival in haemodialysis patients. The link between OPG and aortic stiffening--a consequence of arterial calcification--has not been previously evaluated in this population, and it is not known whether OPG-related mortality risk is mediated by arterial stiffening. METHODS At baseline, OPG and aortic pulse wave velocity (PWV) were measured in 98 chronic haemodialysis patients who were followed for a median of 24 months. The relationship between OPG and PWV was assessed by multivariate linear regression. The role of PWV in mediating OPG related cardiovascular mortality was evaluated by including both OPG and PWV in the same survival model. RESULTS At baseline mean (standard deviation) PWV was 11.2 (3.3) m/s and median OPG (interquartile range) was 11.1 (7.5-15.9) pmol/L. There was a strong, positive, linear relationship between PWV and lnOPG (P = 0.009, model R(2) = 0.540) independent of covariates. During follow-up 23 patients died of cardiovascular causes. In separate univariate survival models both PWV and lnOPG were related to cardiovascular mortality [hazard ratios 1.31 (1.14-1.50) and 8.96 (3.07-26.16), respectively]. When both PWV and lnOPG were entered into the same model, only lnOPG remained significantly associated with cardiovascular mortality [hazard ratio 1.11 (0.93-1.33) and 7.18 (1.89-27.25), respectively). CONCLUSION In haemodialysis patients OPG is strongly related to PWV and OPG related cardiovascular mortality risk is, in part, mediated by increased PWV.

Measurement of pulse wave velocity in children and young adults: a comparative study using three different devices

To estimate the value of pulse wave velocity (PWV) in pediatric cardiovascular disease, prospective studies are needed. Various instruments based on different measurement principles are proposed for use in children, hence the need to test the comparability of these devices in this younger population. The objective of this study was to compare PWV measured by oscillometry (Vicorder (VIC)) with the gold standard of applanation tonometry (PulsePen (PP), Sphygmocor (SC)). PWV was measured in 98 children and young adults (age: 16.7(6.3–26.6) years (median(range)) with the above three devices at the same visit under standardized conditions. Mean PWV measured by VIC was significantly lower than that measured by SC and PP. There was no difference following path length correction of the VIC measurement (using the distance between the jugular notch and the center of the femoral cuff), (PP: 6.12(1.00), SC: 5.94(0.91), VIC: 6.14(0.75) m s−1). Velocities measured by the three devices showed highly significant correlations. Bland–Altman analysis revealed excellent concordance between all three devices, however, there was a small but significant proportional error in the VIC measurements showing a trend toward lower PWV measured by VIC at higher PWV values. Our study provides data on the three most frequently used instruments in pediatrics. Following path length correction of the VIC, all three devices provided comparable results. Thus, our work allows extrapolating data between previously established normal PWV values for children and forthcoming studies using these instruments to assess children at long-term risk of cardiovascular disease. The small proportional error of VIC needs additional technical development to improve the accuracy of the measurements.

Tele-monitoring of home blood pressure.

Received 27 August 2001 Accepted 04 September 200