B.J.R. Junor

Effect of renal-artery stenting on progression of renovascular renal failure

BACKGROUND Placement of renal-artery stents has a high technical success rate in atherosclerotic renovascular disease, but little is known about the clinical benefits of the procedure. We monitored renal function serially before and after stent insertion in patients with renovascular renal failure. METHODS Renal function was assessed before and after stent placement by means of serial serum creatinine values in 32 patients with atherosclerotic renal-artery stenosis. The effect on the progression of renal failure was analysed in 23 patients by comparison of the reciprocal slopes of serum creatinine versus time plots before and after stent placement. FINDINGS 33 transluminal stents were placed in 32 patients with atherosclerotic renovascular disease. Immediate patency was achieved in all cases: the angiographic restenosis rate at 6 months was 12% (n = 24). One patient died after a procedure-related haemorrhage. Median diastolic blood pressure was significantly lower after stenting than before (95 [IQR 86-103] vs 87 [81-90] mm Hg; p > 0.01) but the requirement for antihypertensive drugs was unchanged. Renal function improved or stabilised in 22 (69%) of the 32 patients. Progression of renal failure was significantly slowed after the procedure; the mean (SE) of the slopes of reciprocal serum creatinine values was -4.34 (0.85) L mumol-1 day-1 before stent placement, and -0.55 (1.0) L mumol-1 day-1 after stent placement (p < 0.01, two-sample t test). INTERPRETATION Renal-stent placement in selected patients slows the progression of renovascular renal failure and may delay the need for renal replacement therapy.

Polymorphisms in angiotensin-converting-enzyme gene and progression of IgA nephropathy

We have investigated the influence of the functional insertion (I) and deletion (D) polymorphism in intron 16 of the gene for angiotensin-converting enzyme (ACE) in a retrospective study of 100 patients with IgA nephropathy. There was no difference in genotype frequency compared with normal subjects. However, patients homozygous for the D allele tended to present at an earlier age (medians: DD, 33; ID, 34; II, 42 years) and to require renal replacement therapy at a younger age (medians 37, 42, and 48 years, respectively). The rate of progression was significantly worse in patients homozygous for the D allele. The DD genotype is associated with increased severity of disease in patients with IgA nephropathy.

EFFECT OF ACUTE ALUMINIUM OVERLOAD ON CALCIUM AND PARATHYROID-HORMONE METABOLISM

Accidental exposure of 25 patients on continuous ambulatory peritoneal dialysis to a high aluminium level in the dialysate for a month provided an opportunity to investigate the interrelation between the metabolism of parathyroid hormone (PTH), calcium, and aluminium. After exposure to the high-aluminium dialysate, the mean serum aluminium had risen from 1.85 to 7.11 mumol/l and serum calcium from 2.27 to 2.44 mmol/l, and serum PTH had fallen from 744 to 580 ng/l. After a further 2 months, during which time the dialysate was aluminium-free, the mean serum aluminium and calcium fell to previous levels. There were no changes in calcium or vitamin-D therapy which could have influenced these results. The rise in serum calcium and fall in PTH during a period of aluminium toxicity strongly support the hypothesis that aluminium suppresses PTH through an elevation of serum calcium.

DINITROCHLOROBENZENE SKIN TESTING PREDICTS RESPONSE TO HEPATITIS B VACCINE IN DIALYSIS PATIENTS

The pattern of seroconversion and anti-HBs titres after 3 doses of hepatitis B vaccine was studied in 40 haemodialysis patients who had been grouped on the basis of their cell-mediated immune (CMI) response into strong or weak reactors. CMI response was determined by means of a dinitrochlorobenzene (DNCB) skin test. Titres of anti-HBs were comparable to those in healthy controls in 13 of 14 (93%) strong reactors but in only 9 of 26 (35%) weak reactors. Strong reactors had an equally satisfactory seroconversion rate with either 20 micrograms or 40 micrograms of vaccine whereas weak reactors had a negligible seroconversion rate with the 20 micrograms dose. In terms of hepatitis B prophylaxis, haemodialysis patients with a well preserved CMI response require only 20 micrograms of vaccine, with a consequent saving in cost. In contrast, it will be necessary to devise more effective immunisation schedules for most patients with a poor CMI response.

Ranitidine reduces phosphate binding in dialysis patients receiving calcium carbonate

BACKGROUND In a previous controlled study we showed that ranitidine significantly reduced the phosphate binding of aluminium hydroxide in patients with renal failure, probably increasing intragastric pH. METHODS In this study we have investigated the effect of ranitidine on the phosphate binding of calcium carbonate in fifteen dialysis patients. Ranitidine 300 mg or a placebo tablet was taken before breakfast for two 4-week periods in a double-blind crossover trial with no washout period. The mean daily dose of calcium carbonate was 2 g and neither the dose nor the patients diet was changed during the study period. Blood was taken at 2-weekly intervals for serum phosphate, calcium, albumin, and alkaline phosphatase measurements, and at the end of each treatment period for parathyroid hormone (PTH) level. RESULTS Serum phosphate concentrations were significantly higher during the ranitidine than the placebo phase, 1. 78 (+/-0.43 SD) versus 1.59 (+/-0.49 SD) mmol/l (P<0.001). Serum calcium, albumin, PTH, and alkaline phosphatase concentrations did not differ between the two treatment periods. CONCLUSION This study shows that ranitidine has a significant adverse effect on the phosphate binding of calcium carbonate in patients with renal failure.

Treatment of Postrenal Transplant Erythrocytosis

Fifty-two patients with postrenal transplant erythrocytosis were treated with an angiotensin-converting enzyme inhibitor (lisinopril or enalapril) for a median of 13 months (range 0-44). A significant

Sclerosing Peritonitis—A Further Complication of CAPD

The most common complication of continuous ambulatory peritoneal dialysis (CAPD) is peritonitis which if severe or recurrent may necessitate removal of the peritoneal catheter. A further and serious complication of CAPD is sclerosing peritonitis (ScP). This condition is characterised by a partial or total encapsulation of the small bowel within a dense fibrous cocoon. Nine patients previously treated by CAPD developed ScP. The duration of CAPD ranged from 14 to 40 months and all had recurrent episodes of peritonitis often requiring catheter changes. The clinical features of ScP include recurrent abdominal pain, vomiting, malaise and weight loss preceeded by loss of ultrafiltration on CAPD. All cases required surgery for small bowel obstruction. Four patients died in the immediate post-operative period and two within 3 months from continuing small bowel obstruction. Three patients survived more than one year after operation but one subsequently died from a recurrence of ScP. The etiology of ScP is currently unclear but it represents an extremely serious potential complication of CAPD.

Peritonitis in continuous ambulatory peritoneal dialysis.

The main complication of continuous ambulatory peritoneal dialysis (CAPD) is peritonitis. This paper describes our experience in the diagnosis and management of this complication in 66 patients during the three years to October 1982. The overall incidence of peritonitis was one episode every 6.75 patient months. Staphylococcus albus and Staphylococcus aureus together accounted for 46 per cent of the episodes, and 24 per cent were culture negative. Catheter exit site infections due to Staphylococcus aureus were common and they may have predisposed to peritonitis with gram -ve organisms as well as to staphylococcal peritonitis. Antimicrobial therapy was effective in 60 per cent of peritonitis episodes. The culture negative episodes usually responded to treatment while those due to fungi, though uncommon, did not. Twenty-nine per cent of these CAPD patients were transferred to haemodialysis because of peritonitis which failed to respond to treatment or which recurred repeatedly.

Crescentic Glomerulonephritis: Experience of a Single Unit over a Five Year Period

Crescentic glomerulonephritis is a well defined pathological lesion occurring in a range of renal and systemic diseases. We have retrospectively reviewed the aetiology, clinical features and outcome in 60 patients presenting over a five and a half year period. Most patients were elderly (median age 61 years, range 16–84 years). The majority presented with severe renal impairment, 32 requiring dialysis at admission. The degree of glomerular crescent formation on biopsy was closely related both to initial dialysis dependence and the ensuing response to immunosuppression. Forty-three patients received immunosuppressive treatment. A beneficial response was seen in 40% of patients requiring dialysis, and in 88% of those with less severe renal impairment. A high early mortality was apparent (30% within three months), exclusively affecting elderly patients (all >60 years), with advanced renal failure (all dialysis dependent), the majority of whom (15 out of 18) had been immunosuppressed. The results suggest that the benefits of immunosuppression in this group may be outweighed by the complications of treatment.

Continuous Ambulatory Peritoneal Dialysis: A Three Year Experience

During a three year period 66 patients with end-stage renal failure were commenced on continuous ambulatory peritoneal dialysis (CAPD) at the Western Infirmary, Glasgow. The patient survival and the technique success rates were 86 per cent and 64 per cent at two years respectively. Biochemical and blood pressure control were very satisfactory on a relatively free diet and usually without the need for antihypertensive drugs. The complications next in frequency to peritonitis were catheter obstruction, postural hypotension and excessive weight gain. The mean hospitalisation period per patient per annum was 33 days, with half of this due to peritonitis. Despite selection criteria favouring older patients, diabetics and those with vascular complications, one third of the patients were able to work.