Lipid metabolism in uremia and the effects of dialysate glucose and oral androgen therapy

Factors Affecting Plasma Free Fatty Acids Rise during Hemodialysis

We studied the mechanisms responsible for causing acute changes in plasma lipids during hemodialysis. Dialysis decreased plasma triglycerides to the same extent as when heparin was given without dialysis. Cholesterol increased in proportion to hemoconcentration. Plasma free fatty acids (FFA) levels were also increased, but more so than with heparin alone. Glucose and acetate did not play a role, nor did carnitine loss, and hemofiltration elicited similar effects. The rise in plasma FFA is therefore likely to be caused by other as yet unknown mechanism.

Glucose Concentration in the Dialysate and Lipid Abnormalities in Chronic Hemodialysis Patients

In order to assess the effect of varying glucose concentrations on plasma lipids, we first compared the hormonal response of nine non-diabetic patients during dialysis with a high (200 mg/dl) and a low (100 mg/dl) glucose bath. Insulin and growth hormone production increased (p < 0.05) only with the high glucose bath, and no hemodynamic differences were noted during either dialyses. We then compared lipid profiles of 18 patients for 6 months, changing the glucose dialysate concentrations in each patient after three months. We found that all patients had hypertriglyceridemia, mild hypercholesterolemia, low HDL, normal LDL, and high VLDL cholesterol. We therefore conclude that episodic hyperinsulinemia and episodic excessive growth hormone secretion do not contribute significantly to the lipid abnormalities of the dialysis patients.

Heart surgery in patients under haemodialysis

Several cases of open-heart surgery on patients with severe chronic renal failure have been reported in the last few years. The present study reviews the main problems posed by this situation and analyses our recent experience of three successfully managed patients. Emphasis is made on preoperative preparation, drugs employed in anaesthesia, and postoperative management. We conclude that the prognosis of these patients is good, and that their management is quite similar to that of nephrologically healthy patients.

Glycosylated hemoglobin in patients treated by chronic dialysis

A glycosylated hemoglobin (HbA1) test was used to evaluate the role of dialysate glucose in the development of carbohydrate intolerance and hyperlipidemia in chronic hemodialysis patients and chronic peritoneal dialysis patients. HbA1 levels were significantly elevated in all groups of patients. HbA1 levels were not ameliorated with 8 weeks of glucose-free hemodialysis. There was no correlation between HbA1 and serum glucose, triglycerides, or cholesterol. Thus, HbA1 elevation cannot be explained solely by glucose reabsorption from dialysate. This test is helpful in the detection of carbohydrate intolerance, but its usefulness in evaluation of hyperlipidemia of dialysis patients is uncertain.

Cardiac operation and end-stage renal disease

From 1972-1979, 22 patients with end-stage renal disease underwent 23 cardiac operations involving the pump oxygenator. Fourteen patients had coronary artery bypasss, 2 had aortic valve replacement, 2 had mitral valve replacement (MVR), 2 had MVR with coronary artery bypass, and 2 had ascending aortic root replacement with a composite graft. One patient underwent successful reoperation for a false aneurysm of the left ventricle after MVR. There were 2 postoperative deaths, for a mortality of 9.1%. The patients undergoing coronary artery bypass had an average of 2.7 grafts and an average Functional Class improvement from New York Heart Association Class III or IV to Class I to II. Eighteen patients required preoperative and postoperative dialysis to control blood volume, potassium, and uremia. Four patients had functioning renal transplants, and 4 patients underwent subsequent successful renal transplantation. We conclude that: (1) patients who have transplants and require dialysis can be successfully managed for cardiac operation in spite of their complex associated medical problems; (2) functional and symptomatic improvement simplifies continued management of the patient needing dialysis; and (3) improvement of a cardiac disability can allow favorable renal transplantation in selected patients.

Effect of acute uremia on triglyceride kinetics in the rat

Plasma triglyceride (TG) levesl were elevated 24 hr after the production of acute uremia in rats. The effect of acute uremia on TG production rate was estimated by determining the rate of TG accumulation following Triton WR 1339 inhibition of lipoprotein removal, by measuring hepatic TG secretion rate during in situ liver perfusion, and by quantifying hepatocyte very low density lipoprotein content with the electron microscope. The results of all three of these approaches indicated that TG synthesis and secretion were decreased in acute uremia, suggesting that the associated increase in plasma TG levels had to result from a removal defect. This hypothesis was tested directly by injecting pre-labeled very low density lipoprotein TG into acutely uremic and control rats, and measuring its rate of disappearance from plasma. The t1/2 of removal in acutely uremic rats was found to be approximately twice that of control, confirming the hypothesis that the rise in plasma TG levels in acute uremia is due to a defect in removal of TG from plasma.

Observations on lipid metabolism in chronic renal failure, during conservative and haemodialysis therapy

The main variables of glycolipid metabolism (blood non-esterified fatty acids, triglycerides, cholesterol, insulin, glucose) have been measured in basal conditions in uraemic patients on conservative treatment and on dialysis of different duration and bath glucose concentration (no glucose, 1 g/l, 2 g/l). Basal values for the patients on conservative dietary treatment are not different from normal. In dialysed patients, the blood non-esterified fatty acid and triglyceride concentrations are increased (p less than 0.001) while cholesterol glucose and insulin levels are unchanged. No significant difference is found between the various types of dialysis, having different duration and bath glucose concentration

Factors in the differential rate of arteriosclerosis (AS) between long surviving renal transplant recipients and dialysis patients

In this study, the incidence of clinical and autopsy arteriosclerosis (AS) was studied in over 300 renal transplant patients (RTP) followed in our clinic up to 13 years post-transplant. Of 45 RTP followed a mean of 10.45 years, the incidence of clinical AS was 6% or 0.58% per year at risk. The incidence of death from AS was 2.2% over 10 years or 0.22% per year at risk. There was no apparent tendency for increase of the risk incidence with increasing time post-transplantation up to 13 years. This incidence of clinical and death-related AS in long term RTP contrasts sharply with a quite high incidence of both clinical and death-related AS in long-term dialysis patients as reported by Scribner's group and both the European and U.S. Dialysis Registry. Of our RTP surviving a decade or more, 77% have normal serum triglycerides and 92% are normotensive, again contrasting sharply with a 70-80% incidence of hyperlipidemia and a 60-80% incidence of hypertension in long-term dialysis patients. These studies suggest that the high rate of accelerated AS in dialysis patients is largely reversed by successful renal transplantation, probably due to a lowering of both blood pressure and hyperlipidemia in the long-term RT patients. Practically, these results suggest that the superior survival of transplant patients over dialysis patients already evident at 10 year mark will widen further during the second post-transplantation decade.

Deaths from occlusive arterial disease in renal allograft recipients

In a series of 325 recipients of cadaveric renal transplants sudden occlusive arterial disease was found to be responsible for 12% of deaths. Acute myocardial infarction (9%) occurred 25 times more than expected in the normal population and cerebral thrombosis (3%) 300 times more. The greatest loss was in the initial three-month period after transplantation. Patients with renal failure due to essential hypertension were especially at risk, accounting for six of the 12 deaths.