Hemodynamic effects of endothelin-1 and big endothelin-1 in chronic hemodialysis patients.
(73/8259)
Increased plasma concentrations of endothelin-1 (ET-1) and big endothelin-1 (big ET-1) have been reported in patients with end-stage renal failure (ESRD). In the present study, which included hemodialysis (HD) patients with (n = 21) and without (n = 32) ischemic heart disease, the putative association between plasma levels of ET-1 and big ET-1 and ischemic heart disease and the influence of the dialysis procedure on ET concentrations was investigated. This study also examined in an additional five HD patients without cardiac disease whether intravenously infused ET-1 and big ET-1 (0.2, 1, and 4 pmol/kg per min, each dose for 20 min) preserve their vasoactive potency and whether exogenous big ET-1, which in healthy humans is converted in the kidney, is still converted to ET-1 in ESRD. HD patients with ischemic heart disease demonstrated higher plasma levels of ET-1 and big ET-1 than HD patients without this disorder, and HD reduced plasma ET-1 and big ET-1 concentrations. In HD patients, the big ET-1 infusion, resulting in a 1.5-fold increase in plasma ET-1, caused a more marked and prolonged rise in mean arterial BP than ET-1 (20% versus 13%, P = 0.0001) and a slightly smaller but more prolonged decrease in estimated splanchnic blood flow than ET-1 (37% versus 44%, P = 0.02). Furthermore, big ET-1 lowered heart rate by 9% (P = 0.01) but ET-1 did not. Plasma half-lives of ET-1 and big ET-1 were longer in HD patients than in healthy humans. Thus, ET-1 and big ET-1 preserve their vasoactive potency, and circulating big ET-1 is still converted to active ET-1 in ESRD. Consequently, the increased plasma levels of ET-1 and big ET-1 noted in HD patients, especially in patients with ischemic heart disease, might play a role in the development of uremic cardiovascular complications. (+info)
Management of bacteremia associated with tunneled-cuffed hemodialysis catheters.
(74/8259)
The dominant problem associated with the use of tunneled-cuffed catheters is infection. When this occurs, two issues must be addressed: treatment of the infection and management of the catheter. The purpose of this 2-yr study was to report the results of a prospective observational series in which catheter management was based on the clinical picture presented by the patient. Data were collected on patients with catheter-related bacteremia (CRB) dealt with in one of three ways: (1) minimal symptoms with a normal-appearing tunnel and exit site (exchange over guidewire within 48 h of antibiotic initiation [Xchng group], 49 cases); (2) minimal symptoms but with tunnel or exit site infection (exchange over a guidewire with creation of a new tunnel [Nutunl group], 28 cases); and (3) severe clinical symptoms (catheter removal with delayed replacement after defervescence [Delay group], 37 cases). All cases were treated immediately with empiric antibiotics followed by 3 wk of antibiotic therapy based on culture sensitivities. A cure was defined as a 45-d symptom-free interval after antibiotic therapy was complete. A cure rate total of 87.8% for the Xchng group, 75% for the Nutunl group, and 86.5% for the Delay group was seen for the 114 episodes of CRB. It is concluded that in selected patients, catheter exchange over a guidewire within 48 h of antibiotic initiation followed by 3 wk of specific antibiotic therapy is a viable treatment option. Additionally, replacing the catheter in patients presenting with severe symptoms of sepsis as soon as they have defervesced is a reasonable approach to therapy. (+info)
Effect of histamine H2-receptor antagonist on the phosphorus-binding abilities of calcium carbonate and calcium lactate in hemodialysis patients.
(75/8259)
The effect of histamine H2-receptor antagonist (famotidine) on the phosphorus-binding abilities of calcium carbonate and calcium lactate were examined in 13 chronic hemodialysis patients. In seven patients receiving calcium carbonate, famotidine (20 mg/d) was given because of gastroduodenal disorders, and calcium carbonate was replaced with calcium lactate as a phosphorus binder after 4 wk of treatment with famotidine. With the 4-wk administration of famotidine accompanied by calcium carbonate, the serum phosphorus level increased from 6.3+/-0.9 to 7.1+/-0.5 mg/dl (P<0.05). However, with the substitution of calcium lactate, the serum phosphorus level decreased significantly when compared to that before substitution (6.3+/-0.2 and 6.0+/-0.9 mg/dl after 4 and 8 wk of substitution, respectively), despite continued administration of famotidine. Serum calcium, creatinine, alkaline phosphatase, high sensitive parathyroid hormone, blood urea nitrogen, arterial blood pH, and bicarbonate were not significantly altered during the trial period. In six control patients treated with calcium carbonate alone, there were no statistical changes in serum calcium and phosphorus levels after substitution of calcium lactate for calcium carbonate. These results suggest that famotidine significantly affects the phosphorus-binding ability of calcium carbonate, but not that of calcium lactate. A careful observation of changes in the serum phosphorus level should be required in hemodialysis patients receiving calcium carbonate and histamine H2-receptor antagonists. Calcium lactate may be useful as a phosphorus binder in such hemodialysis patients. (+info)
Plasma total homocysteine and hemodialysis access thrombosis: a prospective study.
(76/8259)
Mild hyperhomocysteinemia, a putative risk factor for atherothrombotic cardiovascular disease morbidity and mortality, may contribute to the excess incidence of atherothrombotic outcomes in the dialysis-dependent end-stage renal disease population. Hemodialysis access (fistula or graft) thrombosis is an unfortunately common and costly morbidity in this patient population. In this study, using a prospective design, the potential relationship between baseline nonfasting, predialysis plasma total homocysteine (tHcy) levels and vascular access-related morbidity was examined in a cohort of 84 hemodialysis patients with a fistula or prosthetic graft as their primary hemodialysis access. Vascular access thrombotic episodes were recorded over a subsequent 18-mo follow-up period. Forty-seven patients (56% of the total) had at least one access thrombosis during the 18-mo follow-up period (median follow-up, 13 mo; rate, 0.6 events per patient-year of follow-up). Proportional hazards modeling revealed that each 1 microM/L increase in the tHcy level was associated with a 4.0% increase in the risk of access thrombosis (95% confidence interval, 1.0 to 6.0%, P = 0.008). This association persisted after adjustment for type of access (fistula versus graft), age, gender, time on dialysis, diabetes, smoking, hypertension, nutritional status, urea reduction ratio, dyslipidemia, and the presence of previous vascular disease. Elevated tHcy levels appear to confer a graded, independent increased risk for hemodialysis access thrombosis. A randomized, controlled trial examining the effect of tHcy-lowering intervention on hemodialysis access thrombosis appears to be justified. (+info)
Impact of aortic stiffness on survival in end-stage renal disease.
(77/8259)
BACKGROUND: Damage to large arteries is a major factor in the high cardiovascular morbidity and mortality of patients with end-stage renal disease (ESRD). Increased arterial stiffness and intima-media thickness, together with increased pulse pressure, are the principal arterial alterations. Whether increased aortic pulse-wave velocity (PWV), a classic marker of increased arterial stiffness, may predict all-cause and/or cardiovascular mortality has never been investigated. METHODS AND RESULTS: A cohort of 241 patients with ESRD undergoing hemodialysis was studied between April 1987 and April 1998. The mean duration of follow-up was 72+/-41 months (mean+/-SD). Mean age at entry was 51.5+/-16.3 years. Seventy-three deaths occurred, including 48 cardiovascular and 25 noncardiovascular fatal events. At entry, together with standard clinical and biochemical analyses, patients underwent echocardiography and aortic PWV measured by Doppler ultrasonography. On the basis of Cox analyses, 2 factors emerged as predictors of all-cause and cardiovascular mortality: age and aortic PWV. Hemoglobin and low diastolic pressure interfered to a smaller extent. After adjustment for all the confounding factors, an OR for PWV >12. 0 versus <9.4 m/s was 5.4 (95% CI, 2.4 to 11.9) for all-cause mortality and 5.9 (95% CI, 2.3 to 15.5) for cardiovascular mortality. For each PWV increase of 1 m/s in our study population, all-cause mortality-adjusted OR was 1.39 (95% CI, 1.19 to 1.62). CONCLUSIONS: These results provide the first direct evidence that in patients with ESRD, increased aortic stiffness determined by measurement of aortic PWV is a strong independent predictor of all-cause and mainly cardiovascular mortality. (+info)
Primary Shewanella alga septicemia in a patient on hemodialysis.
(78/8259)
We report the first Japanese case of primary septicemia with Shewanella alga and also describe the bacteriological characteristics of and results of antibiotic susceptibility tests of the isolate. S. alga was repeatedly isolated, at times simultaneously with Escherichia coli, from the blood of a 64-year-old female undergoing hemodialysis. The isolated organism was determined to be S. alga based on recently published identification criteria, such as hemolysis on sheep blood agar, no acid production from carbohydrates, and growth on agar containing 6. 5% NaCl. Results of antibiotic susceptibility tests demonstrated that the isolate was sensitive to levofloxacin and cefpirome (MICs, 128, 64, and 8 microg/ml, respectively). Although the role of S. alga as a human pathogen has not been fully determined, accumulating data suggest that this organism may be a potential pathogen, especially in compromised hosts. (+info)
Incidence of atherosclerotic arterial occlusive accidents in predialysis and dialysis patients: a multicentric study in the Ile de France district.
(79/8259)
BACKGROUND: An abnormally high mortality from atherosclerotic cardiovascular (CV) accidents has long been reported in patients on maintenance haemodialysis (HD). However, incidence of atherosclerotic CV accidents had not been so far assessed in predialysis patients. In order to evaluate the respective influence of uraemia and the dialysis procedure, we compared incidence of atherosclerotic accidents before and after initiation of HD in a large population of patients. STUDY DESIGN: A total of 748 patients (411 male) were included in a retrospective study based on anamnestic data of patients living on maintenance haemodialysis in March 1993 in nine dialysis units of the Paris area. Incidence of first myocardial infarction (MI) or cerebral infarction (CI) was calculated by reference to the number of years of exposure to the risk both before and after initiation of HD in the various age groups. RESULTS: Overall, 103 first atherosclerotic accidents were recorded, including 10 CI (7 in males) and 93 MI (68 in males). Of the latter, 39 occurred before and 54 after start of HD, at a mean (+/-SD) age of 62.4+/-9.9 and 63.7+/-11.1 years respectively. The annual incidence of MI in males was 8.0, 19.5 and 28.3/1000 patient-years, before and 18.8, 21.6 and 29.9 patient-years after start of HD in the age groups 45-54.9, 55-64.9 and > or = 65 years respectively, compared to figures of 3.4, 7.5 and 10.4/1000 subject-years in the corresponding age groups in the general French population. CONCLUSION: Incidence of atherosclerotic CV accidents is nearly three times higher in uraemic patients than in the general population in the same age range in both genders. The fact that incidence and age at onset of first MI was similar in predialysis and in dialysed patients suggests that the uraemic state per se is a main determinant of such accelerated atherosclerosis. (+info)
Dialysis in neonates with inborn errors of metabolism.
(80/8259)
BACKGROUND: Certain inborn errors of metabolism become manifest during the neonatal period by acute accumulation of neurotoxic metabolites leading to coma and death or irreversible neurological damage. Outcome critically depends on the immediate elimination of the accumulated neurotoxins. Recent technological progress provides improved tools to optimize the efficacy of neonatal dialysis. METHODS: We report our experience with continuous venovenous haemodialysis (CVVHD) in six neonates with hyperammonaemic coma due to urea-cycle disorders or propionic acidaemia and in one child with leucine accumulation due to maple-syrup urine disease (MSUD), in comparison with five patients managed by peritoneal dialysis (PD) (2 hyperammonaemia, 3 MSUD). Application of a new extracorporeal device specifically designed for use in small children permitted the establishment of stable blood circuits utilizing small-sized catheters, and the tight control of balanced dialysate flows over wide flow ranges. RESULTS: Plasma ammonia or leucine levels were reduced by 50% within 7.1 +/- 4.1 h by CVVHD and within 17.9 +/- 12.4 h by PD (P<0.05). Also, total dialysis time was shorter with CVVHD (25 +/- 21 h) than with PD (73 +/- 35 h, P<0.02). A comparison of the CVVHD results with published literature confirmed superior metabolite removal compared to PD, and suggested comparable efficacy as achieved with continuous haemofiltration techniques. Apart from accidental pericardial tamponade during catheter insertion in one case, no major complications were noted with CVVHD. In three of the five PD patients, dialysis was compromised by mechanical complications. None of the MSUD patients but four children with urea-cycle disorders died, two during the acute period and two later during the first year of life, with signs of severe mental delay. Of the eight children presenting with hyperammonaemic coma, the four with the most rapid dialytic ammonia removal rate (50% reduction in < 7 h) survived with no or moderate mental retardation, whereas slower toxin removal was always associated with a lethal outcome. Simulation studies showed that the efficacy of neonatal CVVHD is limited mainly by blood-flow restrictions. CONCLUSIONS: While CVVHD is the potentially most efficacious dialytic technique for treating acute metabolic crises in neonates, utmost care must be taken to provide an adequately sized vascular access. (+info)