Complications of vascular access in hemodialysis (HD)--aged vs adult patients.

Reports on the success of permanent vascular access in elderly HD patients vary considerably. We reviewed the records of 149 patients [62F and 87M] aged 20-89 years old (median 59) who were on hemodialysis for 6-242 (49 median) months, and had undergone 202 vascular access procedures (177 Cimmino-Brescia fistulae and 25 PTFE grafts). Patients were divided into two groups according to the age they started HD. Group A: 48 patients, over 60 years old (range 60-83; median 70) on HD for 43.5, (6-140) months. Group B: 101 patients, under 60 years old, range (15-59) median 46, on HD for 54 (6-242) months. There were no differences between the two groups in terms of gender, primary renal disease, (except polycystic kidney disease), Hct and EPO administration. The initial choice of vascular access, the complications and the technique survival were examined in both groups. Cimmino-Brescia fistulae were used as the first choice of vascular access in all patients except one in group B. PTFE-grafts were the second or third choice in 7/48 (group A) and 15/101 (group B) (p: NS). The only reason for technique failure was vascular thrombosis in both groups (11/48 group A and 31/101 group B p: NS). Other complications were: aneurysms (10/48 and 14/101, p: NS), infections (0/48 and 2/101 p: NS) and edema (0/48 and 6/101, p: NS). Five-year technique survival of the first AV fistula in the two groups was 35% and 45% respectively (log-rank test, p: NS). These findings suggest that: a) A.V. fistula is the first choice of vascular access in aged HD patients; b) There is no difference in vascular access complications across age groups; c) Survival of the first A.V. fistula is independent of age.

The effect of the correction of metabolic acidosis on nitrogen and potassium balance of patients with chronic renal failure.

Nitrogen and potassium balance studies were conducted in six nondialyzed uremic patients. Each patient was investigated before and after supplementation with sodium bicarbonate and sodium chloride. Every period of the study lasted longer than 1 wk. Each patient had the same calorie and protein intake during the whole study. Urea nitrogen appearance was correlated with protein intake for the assessment of the compliance of patients with their diets. There was a significant decrease of blood urea nitrogen (p = 0.014) of 36% during bicarbonate supplementation and both metabolic balance studies improved significantly (p = 0.0005 and 0.0096). However, there was no significant improvement during sodium chloride administration indicating that the effect of bicarbonate was the result of the correction of metabolic acidosis and not of the expansion of the extracellular volume.