Effect of extracorporeal blood cooling on dialytic arterial hypotension.
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Blood↗
Biomedical subjects
C Zoccali
Publications and source records attributed to C Zoccali.
[Functional relationships between plasma renin activity and hemodynamic indices in essential arterial hypertension].
Vasoconstriction-volume analysis postulates that arteriolar vasoconstriction is the mechanism of blood pressure elevation in patients with "high-renin" essential hypertension while a volume expanded state with relatively dilated arterioles sustains "low renin" essential hypertension. To test this hypothesis we carried out hemodynamic and PRA studies in 43 essential hypertensives. Cardiac index was directly related to PRA (r=0,41; p less than 0,01), by contrast, peripheral vascular resistances and plasma volume were unrelated to PRA. The data do not support the bipolar hypothesis since vasoconstriction and volume expansion are associated with unpredictable changes in PRA. The direct relationship between CI and PRA may be interpreted as the result of a common factor (presumably sympathetic nervous system) governing both functions.
Adult↗
[Cardiac output and pulmonary blood volume in arterial hypertension of chronic uremia].
To investigate the mechanisms that sustains arterial hypertension in chronic uremia we performed hemodynamic studies in 13 dialysed uremics by means selective radiocardiography (Donato-Giuntini method). The 5 dialysed patients with dialysis controllable hypertension (GROUP B) had higher cardiac indexes (CI) respect to the 8 dialysed normotensive controls (GROUP A) (CI: Group B 4,250 l/min/m2, Group A 3,610 l/min/m2; p less than 0,05). The higher CI in group B appeared independent from the degree of anemia because the two groups had comparable hematocrit values (Hct:Group B 26,2% Group A 26,4%); On the other hand the slight blood volume expansion we observed in group B (7%) respect to group A hardly explains the observed difference in CI. It is interesting that pulmonary blood volume/total blood volume ratio (PBV/TBV) was significantly higher in dialysed hypertensives (PBV/TBV: Group B 14,26%, Group A 11,15%; p less than 0,05) The higher PBV/TBV can be the result of a decrease in venous compliance and could explain the higher CI in group B; further studies however are warranted to elucidate this point.
Adult↗
Chronic hemodynamic effects of propranolol treatment in dialysis-refractory hypertension.
The hemodynamic mechanism of the hypotensive effect of propranolol was studied by quantitative radiocardiography in 8 patients with dialysis-resistant hypertension. Propranolol treatment brought about a decrease in mean arterial pressure and peripheral vascular resistances. The cardiac index was slightly reduced only in the early stage of the treatment. No significant difference was found between patients on treatments lasting longer than 3 months and patients with dialysis-controlled hypertension. The results show that propranolol can be used safely as the sole antihypertensive agent in patients with dialysis-resistant hypertension.
Adult↗
Long-term propranolol treatment of resistant arterial hypertension in haemodialysed patients.
1. Propranolol was given to eight haemodialysed patients with resistant arterial hypertension for periods ranging from 6 to 16 months. 2. The treatment brought about an excellent control of blood pressure in all cases. 3. After withdrawal of propranolol plasma renin activity rose on average 40% compared with the value obtained during treatment. However, no significant relationship was found between the change in plasma renin activity and the change in the diastolic blood pressure. 4. Stopping propranolol resulted in a prompt rebound of arterial pressure toward pretreatment values. However, hypertension was always controlled on resuming drug treatment. 5. The results show that this form of hypertension can be controlled on a long-term basis with propranolol. However, the effect on blood pressure seems not to be mediated by suppression of renin secretion.
Adult↗
Propranolol treatment of resistant arterial hypertension in patients on chronic dialysis.
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Body Weight↗
Plasma concentration of asymmetrical dimethylarginine and mortality in patients with end-stage renal disease: a prospective study.
BACKGROUND: The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric-oxide synthase, which has been linked to endothelial dysfunction and atherosclerosis in the general population, is raised in patients with end-stage renal disease and could contribute to the high cardiovascular risk in patients with chronic renal failure. We investigated the relation between cardiovascular risk factors and plasma ADMA concentration in a cohort of haemodialysis patients (n=225), and tested the predictive power of ADMA for mortality and cardiovascular outcomes. METHODS: Patients had standard dialysis three times a week. We accurately recorded cardiovascular events over a mean follow-up of 33.4 months (SD 14.6); these events were reviewed by a panel of physicians. We identified correlates of plasma ADMA by univariate and multivariate analyses. FINDINGS: On univariate analysis, ADMA concentration in plasma was directly related to concentrations of fibrinogen and L-arginine in plasma, duration of dialysis treatment, and serum cholesterol concentration, and was inversely related to serum albumin concentration. On multivariate analysis, only plasma fibrinogen (p=0.0001) and serum albumin (p=0.04) concentrations were independently related to plasma ADMA concentration (multiple r=0.44, p=0.0001). 83 patients died, 53 (64%) by cardiovascular causes. In a Cox's proportional-hazards model, plasma ADMA ranked as the second factor predicting overall mortality (hazard ratio 1.26, 95% Cl 1.11-1.41, p=0.0001) and cardiovascular events (1.17, 1.04-1.33, p=0.008). INTERPRETATION: In haemodialysis patients, plasma ADMA is a strong and independent predictor of overall mortality and cardiovascular outcome. These findings lend support to the hypothesis that accumulation of ADMA is an important risk factor for cardiovascular disease in chronic renal failure.
Arginine↗
Smoking, blood pressure and serum albumin are major determinants of carotid atherosclerosis in dialysis patients. CREED Investigators. Cardiovascular Risk Extended Evaluation in Dialysis patients.
AIM: To investigate the relationship between carotid atherosclerosis and some major cardiovascular risk factors in uremic patients on chronic dialysis. METHODS: A cross-sectional study was carried out in 119 unselected dialysis patients (89 on hemodialysis and 30 on chronic ambulatory peritoneal dialysis, CAPD). Fasting blood sampling for serum lipids, albumin, hemoglobin, and echo-colour-Doppler evaluation of common carotid arteries were performed in all patients (during the non-dialysis day in hemodialysis patients). In hemodialysis patients BP was measured before and after dialysis; in CAPD patients home BP values were recorded during the month before the study day. RESULTS: Ninety-five patients had at least one plaque and 57 had at least four plaques. Thirty-eight had mild and eleven severe carotid stenosis. In multiple regression models, the mean internal diameter of carotid arteries was explained (R=0.52, P=0.0001) by systolic pressure (r=0.39), serum cholesterol (r=-0.28), age (r=0.27) and smoking (r=0.24) while the degree of carotid stenosis was predicted (R=0.39, P=0.0001) by age (r=0.36) and smoking (r=0.25). The number of atherosclerotic plaques was explained (R=0.51, P=0.0001) by age (r=0.36), smoking (r=0.25) and pulse pressure (r=0.20), serum albumin just failing to reach statistical significance (P = 0.06). However, serum albumin was a significant and independent predictor of the number of atherosclerotic plaques (r=-0.26) in hemodialysis patients (n=89). Sex, diabetes, Kt/V, duration of dialysis treatment, hemoglobin, serum calcium and phosphate did not add any predictive power to the models. CONCLUSIONS: In dialysis patients arterial pressure and smoking are associated with carotid atherosclerosis. Serum albumin appears to serve as an independent predictor of carotid atherosclerosis.
Arteriosclerosis↗
An evidence-based nephrology column in the JN.
Evidence-based medicine (EBM) combines clinical experience with the best available patient-centred medical knowledge. EBM is not restricted to randomised trials and meta-analyses. It involves finding the best studies (the best "external evidence") to answer the clinical questions we face in everyday clinical practice. This is a challenging framework where medical decisions absolutely cannot be based on a superficial or automatic approach to patient care. Interest in this approach is growing fast. The EB Nephrology Section of the Journal of Nephrology aims to help readers to update and extend their knowledge of the foundations, the tools and the products of EBM, with specific applications in the field of clinical nephrology.
Evidence-Based Medicine↗
The cost of knowledge in nephrology and the importance of clinical databases.
The modern clinician uses knowledge generated on the solid ground of clinical epidemiology as a basis for clinical practice. Doctors play a leading role in continuous quality improvement of medical services, working to find and validate appropriate clinical performance measures. Large clinical databases are emerging as an important research tool for testing the performance of clinical policies in patients with chronic renal diseases. New strategies have been devised to help the clinical investigator decide when to base clinical policies on observational or randomized trial data. In the next few years the high motivation and consensus required in clinical research projects based on large data bases will certainly be created and the tantalizing managerial problems resolved.
Clinical Trials as Topic↗
Prediction and consistency of blood pressure salt-sensitivity as assessed by a rapid volume expansion and contraction protocol. Salt-Sensitivity Study Group of the Italian Society of Hypertension.
BACKGROUND: This multicenter trial in essential hypertensive patients (n=94) is aimed i) to evaluate the distribution of blood pressure salt-sensitivity by a rapid volume expansion/contraction protocol over three days; ii) to investigate the within-patient reproducibility and to identify predictors of the response to the test; iii) to compare this response with the response to dietary NaCl restriction. METHODS: The study design included: 1) screening for salt-sensitivity by the rapid test; 2) a controlled trial of dietary salt restriction; 3) repetition of the rapid test in a subgroup of patients. RESULTS: The mean BP response to the rapid test fitted a Gaussian curve. In multivariate regression analysis, controlling for the effect of potential confounders, the blood pressure increment during the intravenous saline infusion was the best independent predictor of the response to the test (r=0.713) with minor contributions by the 24-h urinary sodium excretion before the test and by baseline fasting serum insulin. These three variables together explained 61% of the overall variability of the response. The Spearman rank correlation coefficient between the BP response to the rapid test and the response to the dietary protocol was 0.21, p=0.05. Upon repetition of the rapid test, the correlation coefficient between the responses observed on the two occasions was 0.60 (n=19, p<0.01); there were no patients misclassified across the extreme tertiles of the distribution of salt-sensitivity. CONCLUSION: We conclude that the rapid test reproducibly identified patients in the upper and lower parts of the distribution of salt sensitivity. The analysis of possible predictors of the response to the test suggested that the evaluation of the blood pressure response to saline infusion, upon careful standardization of dietary NaCl intake, may represent an alternative to the completion of the whole test for the screening of the salt-sensitivity.
Adult↗
Renal endothelin-1 is linked to changes in urinary salt and volume in essential hypertension. Salt Sensitivity Group of the Italian Society of Hypertension.
METHODS: We investigated the influence of salt intake on urinary and plasma endothelin-1 (ET-1) in 55 patients who entered a two-week double-blind, randomised, crossover study comparing a 50 mMol/day salt intake and 150 mMol/day. Twenty-four-hour ET-1 excretion and plasma ET-1 were measured by RIA on pre-extracted samples. RESULTS: In the whole cohort (n=55), changes in urinary ET-1 were related to salt excretion (r=0.28, P=0.04) and urinary volume (r=0.47, P=0.0001). In a multivariable model, changes in PRA, plasma aldosterone, blood pressure and heart rate did not add any predictive power to salt excretion with regard to urinary ET-1 variations. The relationship between urinary volume and urinary ET-1 was stronger than that of urinary sodium with ET-1 excretion because sodium was excluded from the multivariable model when urinary volume was introduced. Changes in urinary ET-1 were unrelated to mean blood pressure changes (P=0.66). Changes in plasma ET-1 were unaffected by changes in salt intake (P=0.58) but were strongly related to those in PRA (r= -0.45, P=0.01) and plasma aldosterone (r= -0.53, P=0.002). CONCLUSIONS: The renal excretion of ET-1 is influenced by changes in salt intake and appears largely independent of the blood pressure response to salt. Changes in urinary volume which accompany variations in salt excretion play an important role in this response. Since urinary ET-1 reflects its renal synthesis, our data support the notion that renal ET-1 plays a role in the regulation of sodium balance in patients with mild hypertension.
Adult↗
Pentosidine, carotid atherosclerosis and alterations in left ventricular geometry in hemodialysis patients.
OBJECTIVE: To assess the relationship between advanced glycation end products (AGE) and cardiovascular damage in end-stage renal diseases. METHODS: Ninety-one hemodialysis patients who had been on dialysis treatment for at least six months were recruited for the study. Each patient underwent echocardiography and an echo-color Doppler study of the carotid arteries. We measured plasma pentosidine and related it to intima media thickness, atherosclerotic plaques and parameters of left ventricular geometry. RESULTS: Pentosidine was higher in patients treated by low-flux dialysis (31.0+/-16.6 pmol/mg protein) than in those treated by high-flux dialysis (25.4+/-7.6 pmol/mg protein), but this difference was of marginal statistical significance (P=0.08). On multivariate analysis, plasma IgG (beta=0.24, P=0.02) was the only independent correlate of plasma pentosidine. Intima media thickness and the number of atherosclerotic plaques were unrelated to plasma pentosidine. Mean wall thickness (beta=0.18, P<0.05), relative wall thickness (beta=0.20, P<0.05) and left ventricular end-diastolic volume (beta= -0.23, P<0.01) were independently related to plasma pentosidine. CONCLUSIONS: Pentosidine, a reliable marker of "carbonyl stress", is unrelated to intima media thickness and to the number of atherosclerotic plaques, but it is related to alterations in heart geometry. These data suggest that the effect of carbonyl stress on the cardiovascular system is complex and that the effects of AGE on the heart may be dissociated from those on the arterial system.
Arginine↗
The importance of large, high quality clinical databases in nephrology.
While clinical trials constitute an undisputed standard, they are not perfect because they are focused on a well defined segment of patients with a given disease. Generalizability is a problem with these studies because the experimental setting often differs substantially from everyday clinical practice. Clinical files are traditionally the main source of information for clinical medicine. The quality of recorded information in clinical files is often unsatisfactory. Yet clinical files are data-rich and ought to be considered as a valuable resource, particularly when clinical information is stored in electronic format. Clinicians have already started to construct very large, high quality clinical databases. Outcome research based on high quality data retrieved from well organized and exhaustive clinical files is bound to become increasingly important. Standardization is fundamental for these projects to be successful. The task may be daunting but worth while; due to complexity and cost the randomised clinical trial is unlikely to remain the only source of information on which to base clinical decisions about treatments.
Clinical Trials as Topic↗
[Multiple reuse of the capillary kidney by washing with 0.25 M NaOH].
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Humans↗
[Long-term treatment with propranolol of hypertension resistant to dialysis].
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Adult↗
[Nephropathy associated with arterial hypertension: genes and Barker's hypothesis].
For about three decades glomerular diseases have been the most intensively investigated research area in nephrology. The increasing proportion of patients with end-stage renal disease (ESRD) secondary to hypertension has now revived interest in hypertension. Prospective studies have firmly established that high blood pressure is associated with an increased risk of renal failure independent of other risk factors. Hypertension-related renal injury might be interpreted in a general context taking into account genes, intrauterine growth and environmental factors. Disturbed intrauterine growth (due to malnutrition or other factors) has a negative influence on the development of the cardiovascular system and favours the occurrence of hypertension, insulin resistance, hypercholesterolaemia and hyperuricaemia in adult life (Barker's hypothesis). Altered intrauterine growth has also been associated with a reduced number of nephrons at birth. Damage attributable to glomerular hyperperfusion in kidneys with a reduced number of nephrons is aggravated by vascular lesions in middle and small arterial vessels (secondary to hypertension, hyperlipidaemia and environmental risk factors such as smoking). The observation that subjects homozygous for the D allele of the ACE gene are predisposed to both cardiovascular complications and nephrosclerosis, suggests that genetic factors may interact with altered intrauterine growth in determining the risk of cardiovascular and renal diseases.
Alleles↗
[Xerostomia and Xerophthalmia in haemodialysis patients].
BACKGROUND: A reduction in salivary and lachrymal secretion has been described in many pathologies; however, such alterations have not been described in patients with renal failure. This study was designed to estimate the frequency of alterations in salivary and lachrymal secretion in haemodialysed patients. PATIENTS ABD METHODS: We studied 63 haemodialysed patients and 23 healthy control subjects. In all of them we tested salivary secretion (Saxon test), lachrymal secretion (Shirmer test) as well as the presence of symptoms of xerostomia and xerophthalmia. In a subgroup of patients We investigated any evidence of ocular lesions and tissue damage of salivary glands (histopathology). We also tested the correlation between salivary and lachrymal secretion and autonomic nervous system function. Furthermore, we also studied the association between xerostomia and xerophthalmia and serum auto antibodies (anti nuclear, anti-Ro (SS-A), anti-La (SS-B)) and anti HCV antibodies. RESULTS: On average salivary and the lachrymal secretion was markedly reduced in uraemic patients compared with healthy controls. We found the alterations in salivary glands function to be strongly related to salivary glands fibrosis and atrophy and independent of amyloid accumulation. On the other hand, we observed that xerostomia and xerophthalmia were unrelated to autonomic dysfunction as well as to HCV infection and circulating auto antibodies. Moreover, xerophthalmia was frequently associated with evidence of corneal damage. CONCLUSIONS: Reduced salivary and lachrymal secretion is frequent in uraemic patients. Such alterations are often asymptomatic and could be an expression of the accelerated age-dependent decline in glandular function and the attendant fibrosis and atrophy.
Adolescent↗