Medicien

Despite increasing financial and human resources invested, the disappointing rate of hypertension (HT) control continues to pose a challenge to health care providers in the civilized world. Low HT control is associated with the poor patient compliance. Nowadays, SBPM is an accepted method to improve the patient compliance as well as HT control. However SBPM has several limitations such as:By using telemedicine in the SBPM, a virtual HT clinic can be built up. In our developed system (TensioPhone/TensionCare) we remind the patient the BP measurement and pill intake, and SBP data are automatically transferred to the center for analysis. The analysed and structured data are then sent to the physician and the patient as a printed report. Regular communication between the health care team and the patient can contribute to make the virtual hypertension clinic become a reality and to substantially improve HT control rates.

Clinical guidelines for decision-making in chronic kidney disease (CKD) consider parathormone (PTH) levels. The measured PTH values differ if novel full length PTH(1-84) assays are used instead of earlier intact iPTH assays. In this study we analyzed how the classification of CKD patients alters when iPTH assays are switched to PTH(1-84) assays. Plasma samples were collected prior to dialysis sessions from 110 consecutive CKD patients on maintenance hemodialysis. PTH levels were determined with iPTH assays (Elecsys, Architect and DiaSorin Liaison N-tact) and PTH(1-84) assays (Elecsys and Liaison). Using KDIGO guidelines patients were classified as being below, above and in the recommended target range (RTR) of PTH. The results of classification with different assays were evaluated and, a novel calculation method of RTR was implemented. The prevalence of patients with PTH in RTR is comparable with each assay, but the individual patients differed. PTH(1-84) Elecsys and Liaison assays classified more patients as being below RTR than iPTH Elecsys and Architect but not Liaison N-tact assay (27.3%, 22.7% vs. 41%, 31.8%, and 36.4%, respectively). In turn, PTH(1-84) Elecsys and Liaison assays identified less CKD patients with PTH above the RTR than iPTH except N-tact assays (6.4%, 10% vs. 16.3%, 19%, and 6.3%, respectively). Using our calculation method, our discrimination values for PTH(1-84) assays to achieve classification identical to that with iPTH Elecsys were lower than those recommended by the manufacturer. Current guidelines for the treatment of secondary hyperparathyroidism in CKD should consider the type of assays used for PTH measurement. Each laboratory should assess its own RTR for PTH tests to achieve comparable classification. The presented calculation is simple, it mimics an everyday situation, switching from one assay to another one, and provides useful RTR values for PTH tests.

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 night's 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.

Frequent or occasional symptomatic intradialytic hypotension during hemodialysis may influence patients' well being, but its effects on survival, independent of comorbidities, have not previously been investigated.Objective:  To assess the effect of frequent (f-IDH) or occasional (o-IDH) dialysis-associated hypotension on survival.Methods:  During the run in period in 1998, 77 patients with f-IDH (≥10 hypotensive events/10 months, responding only to medical intervention) and 101 patients with o-IDH (1 or 2 events/10 months) were identified among all 958 prevalent chronic hemodialysis patients of a network. Eighty-five patients who had no hypotensive episodes (no-IDH) served as controls. Patients were followed for a median of 27 months (range 0.3–37), and survival of patients was compared by log-rank test. Independent association of f-IDH and o-IDH on survival, compared to no-IDH, was assessed by proportional hazards model that included patient's demographics, laboratory data, comorbidity as well as medications.Results:  Forty-five patients (58%) with f-IDH, 47 (47%) with o-IDH, and 33 (39%) with no-IDH died during the follow up that represents mortality rates of 37 (p = 0.013 vs. no-IDH), 26 (p = 0.375 vs. no-IDH), and 21 deaths/100 patient years in the three groups, respectively. In multivariate proportional hazards regression, where age, sex, time on dialysis, CHD, diabetes, Kt/V, albumin level, use of beta-blockers, calcium-channel blockers, and long-acting nitrates have been adjusted for, neither f-IDH nor o-IDH was associated with survival.Conclusion:  Mortality in patients with f-IDH is significantly higher than in those without such events. Our data, however, did not provide evidence that f-IDH, independent of age and comorbidities, contributes to mortality in these patients.

Experimental and clinical trials in the field of bone biology helped to clarify the role of receptors, which belong to the tumor necrosis factor family, such as osteoprotegerin and receptor activator of nuclear factor kappaB (RANK), in the regulation of bone remodeling. The ligand of the receptor activator of nuclear factor kappaB (RANKL) is a stimulator of bone resorption, while osteoprotegerin is the soluble "decoy" receptor to RANKL, protecting thereby bone from resorption. Pathological states of bone remodeling (like osteoporosis) are associated with imbalance in the activity of osteoprotegerin and the receptor activator of nuclear factor kappaB. Recent studies, however, also indicate that the osteoprotegerin/RANKL/RANK system has important roles in the regulation of the immune and vascular system as well. In this review we summarize the function and regulation of osteoprotegerin, its role in pathological states--primarily in cardiovascular diseases--and its relevance as a marker of cardiovascular risk. Finally, we present our prospective trial performed among the chronic dialyzed patients, where we examined the association between the cardiovascular mortality, osteoprotegerin levels and the arterial stiffness.

Previous studies demonstrated that different parameters of arterial stiffness are related to cardiovascular mortality in hemodialysis patients. The relative prognostic value of these parameters has not previously been evaluated in one cohort. Carotid-femoral pulse wave velocity, carotid augmentation index, carotid pulse pressure and carotid-brachial pulse pressure amplification were measured in 98 patients before and after hemodialysis. Patients were followed for a median of 29 months (1-34) and the association of these parameters with cardiovascular mortality was assessed using log-rank tests and Cox proportional hazards regressions. During follow-up, 40 patients died (mortality rate 20.7/100 patient-year), of which 25 died of cardiovascular causes. Increasing pre- and postdialysis pulse wave velocity tertiles and decreasing predialysis pulse pressure amplification tertiles were significantly related to cardiovascular mortality (p-values are 0.012 and 0.011 for pre- and postdialysis pulse wave velocity, and <0.001 and 0,321 for pre- and postdialysis pulse pressure amplification, respectively). Neither the carotid augmentation index nor carotid pulse pressure was related to cardiovascular mortality. In the Cox-regression, the adjusted hazard ratios for 1 m/s higher pre- and postdialysis pulse wave velocity were 1.24 (1.07-1.44) and 1.17 (1.06-1.28), respectively. The hazard ratio for 10% lower predialysis pulse pressure amplification was 1.41 (1.03-1.92). When included in the same model, both predialysis pulse wave velocity and pulse pressure amplification remained significantly associated with cardiovascular mortality (relative risk: 1.23 [1.07-1.42] and 1.39 [1.02-1.89]). Among different stiffness parameters, pulse wave velocity is consistently related to cardiovascular mortality, irrespective of the timing of measurement. Predialysis pulse pressure amplification seems to provide additional prognostic information.

Sponsorship: This study was supported by grants-in-aid from the Medical Research Council of Canada (MT12579), Heart and Stroke Foundation of Ontario (NA3664) and the Kidney Foundation of Canada. Dr Tisler was a renal fellow from the Ist Department of Medicine, Semmelweis ...

The thiazide-sensitive Na-Cl cotransporter (TSC) is involved in the fine regulation of sodium excretion by the kidney, and an increase in its activity causes salt-sensitive hypertension and hypercalciuria. To explore the possibility that activating mutations in the TSC gene may be involved in the pathogenesis of primary hypertension, we screened genomic DNA of 68 individuals from hypertensive families of patients with hypercalciuria for variations using single-strand conformation polymorphism and investigated the functional properties using the Xenopus laevis oocyte expression system. We identified 18 variants in the TSC and, of those, four were nonsynonymous. The A728T, R904Q and R919C variants were introduced into the human TSC cDNA and expressed in Xenopus oocytes to study their effect on Na transport. Although T728 and Q904 did not show any difference in Na uptake, the R919C mutant showed a 60% increase compared to wild-type human TSC and an exaggerated inhibitory action of hydrochlorothiazide. Immunocytochemical analysis revealed no difference in cell surface expression of R919C mutants compared to wild-type hTSC. There was no significant difference in the inhibitory effect of the carboxyl terminus of the serine-threonine kinase WNK4 on the R919C mutant and wild-type hTSC. Our results show that the substitution of arginine for cysteine at position 919 of TSC increases Na transport function, and provide support for the hypothesis that mutations in renal tubular sodium transporters may contribute to the development of primary hypertension, a polygenic disorder, by increasing renal sodium reabsorption.

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. 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. 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. 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.