J.D. Briggs

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.

REVERSAL OF ACUTE CLINICAL AND EXPERIMENTAL ORGAN REJECTION USING LARGE DOSES OF INTRAVENOUS PREDNISOLONE

Abstract The ability of single large (1 g.) doses of intravenous prednisolone to reverse rejection episodes has been investigated clinically and experimentally. Sixteen renal-transplant recipients have been treated in this way. The oral dose of prednisone was not increased during these episodes and no additional treatment was given. This therapy reversed 86% of rejection crises without any toxic effects. One patient has died from infection, 1 month after transplantation. Using the heterotopic rat-heart-transplant model the ability of intravenous prednisolone, antilymphocyte serum (A.L.S.), intraperitoneal prednisolone, and azathioprine to reverse rejection in recipients immunosuppressed with a single dose of A.L.S. at the time of transplantation were compared. Intravenous prednisolone was the only successful agent and prolonged survival by 9±3 days.

Outcome of renal replacement treatment in patients with diabetes mellitus.

OBJECTIVE--To compare the outcome of renal replacement treatment in patients with diabetes mellitus and in non-diabetic patients with end stage renal failure. DESIGN--Retrospective comparison of cases and matched controls. SETTING--Renal unit, Western Infirmary, Glasgow, providing both dialysis and renal transplantation. PATIENTS--82 Diabetic patients starting renal replacement treatment between 1979 and 1988, compared with 82 matched non-diabetic controls with renal failure and 39 different matched controls undergoing renal transplantation. MAIN OUTCOME MEASURES--Patient characteristics, history of smoking, prevalence of left ventricular hypertrophy and myocardial ischaemia at start of renal replacement treatment; survival of patients with renal replacement treatment and of patients and allografts with renal transplantation. RESULTS--The overall survival of the diabetic patients during the treatment was 83%, 59%, and 50% at one, three, and five years. Survival was significantly poorer in the diabetic patients than the controls (p less than 0.001). Particularly adverse features for outcome at the start of treatment were increasing age (p less than 0.01) and current cigarette smoking (relative risk (95% confidence interval) 2.28 (0.93 to 4.84), p less than 0.05). Deaths were mainly from cardiac and vascular causes. The incidence of peritonitis in patients on continuous ambulatory peritoneal dialysis was the same in diabetic patients and controls (49% in each group remained free of peritonitis after one year), and the survival of renal allografts was not significantly worse in diabetic patients (p less than 0.5). CONCLUSIONS--Renal replacement treatment may give good results in diabetic patients, although the outlook remains less favourable than for non-diabetic patients because of coexistent, progressive vascular disease, which is more severe in older patients.

ENDOGENOUS CELL-MEDIATED IMMUNITY, BLOOD TRANSFUSION, AND OUTCOME OF RENAL TRANSPLANTATION

The cell-mediated immunity (CMI) of a group of patients on regular dialysis was measured by a quantitative dinitrochlorobenzene (DNCB) skin test, the reaction being graded 0--15. The score in these patients varied widely, although the mean was much lower than that occurring in a group of 15 healthy subjects. 55 cadaveric renal allografts were subsequently done in 51 of these patients, and graft survival was assessed at 6 months. The 39 patients with weak DNCB skin reactions had a much higher graft survival (71%) than did the 12 with strong reaction (15%) (p less than 0.01). The weak DNCB reactors also had more pre-transplant blood transfusions. The findings suggest that the CMI of the recipient as measured by the DNCB test has an important influence on subsequent graft survival. This influence may partly be related to pre-transplant blood transfusion.

Methods of forced diuresis and its application in barbiturate poisoning.

Abstract In a series of 110 cases of severe barbiturate intoxication treated by means of forced diuresis there were only 2 deaths, and no serious side-effects. Comparison of forced diuresis with unassisted renal excretion showed that considerably more barbiturate was removed in unit time with forced diuresis, although the effect was more pronounced with phenobarbitone and cyclobarbitone than with the other intermediate-acting drugs. Study of the methods used to induce and maintain forced diuresis suggested that a simple regimen of fluid infusion was adequate, and that the type of diuretic used was not important, except that alkalinisation was valuable in poisoning with phenobarbitone.

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.

Results of Nephrectomy in Hypertension Associated with Unilateral Renal Disease

Nephrectomy has been carried out in 34 patients with hypertension associated with unilateral parenchymal renal disease (28 with unilateral pyelonephritis, 3 tuberculosis, 2 hypoplasia, and 1 adenocarcinoma). In 13 of the patients the blood pressure was corrected, in four it was improved, and in 17 it was unaffected. The intravenous pyelogram (by the infusion technique with nephrotomography if necessary) and renogram give adequate information in most patients with unilateral parenchymal renal disease but may need to be supplemented by aortography, or retrograde pyelography, or divided renal function studies in a few special circumstances. When the function of the damaged kidney is less than 25% of the total (which is well maintained), and the contralateral kidney is intact, nephrectomy is recommended provided the hypertension is significant; success is more likely in younger patients with a short history of hypertension.

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

INHIBITION OF Fc-ROSETTE FORMATION BY SERUM OF PATIENTS WITH RENAL ALLOGRAFT REJECTION

Abstract A test which measures the inhibition of Fc-rosette formation by the patients serum was used in a group of 23 renal allograft re- cipients. All 13 serum samples obtained during acute rejection and 2 of 3 obtained during chronic rejection showed strong inhibitory activity, suggesting that the test is of value in confirming the presence of rejection. Its value as a predictive test remains to be established. Preliminary experiments suggest that both immune com- plexes and alloantibodies copntribute to the observed in- hibition of Fc-rosette formation.