Serial changes in renal function and blood flow after nephrectomy

Measurements of glomerular filtration rate and effective renal plasma flow were carried out on 10 patients prior to unilateral nephrectomy for a variety of causes including 2 living related donors. The measurements were repeated at one day, one week, and one month postoperatively. The pattern of change in both glomerular filtration rate and effective renal plasma flow depended on the nature of the removed kidney, and an explanation for these early changes is proposed.     

Immediate postoperative renal function deterioration in cardiac surgical patients predicts in-hospital mortality and long-term survival

Postoperative renal function deterioration is a serious complication after cardiac surgery with cardiopulmonary bypass and is associated with increased in-hospital mortality. However, the long-term prognosis of patients with postoperative renal deterioration is not fully determined yet. Therefore, both in-hospital mortality and long-term survival were studied in patients with postoperative renal function deterioration. Included were 843 patients who underwent cardiac surgery with cardiopulmonary bypass in 1991. Postoperative renal function deterioration (increase in serum creatinine in the first postoperative week of at least 25%) occurred in 145 (17.2%) patients. In these patients, in-hospital mortality was 14.5%, versus 1.1% in patients without renal function deterioration (P < 0.001). Multivariate analysis significantly associated in-hospital mortality with postoperative renal function deterioration, re-exploration, postoperative cerebral stroke, duration of operation, age, and diabetes. In patients who were discharged alive, during long-term follow-up (100 mo), mortality was significantly increased in the patients with renal function deterioration (n = 124) as compared with those without renal function deterioration (hazard ratio 1.83; 95% confidence interval 1.38 to 3.20). Also after adjustment for other independently associated factors, the risk for mortality in patients with postoperative renal function deterioration remained elevated (hazard ratio 1.63; 95% confidence interval 1.15 to 2.32). The elevated risk for long-term mortality was independent of whether renal function had recovered at discharge from hospital. It is concluded that postoperative renal function deterioration in cardiac surgical patients not only results in increased in-hospital mortality but also adversely affects long-term survival.     

Diltiazem infusion for renal protection in cardiac surgical patients with preexisting renal dysfunction

OBJECTIVE: To evaluate if the calcium channel blocker diltiazem protects postoperatively renal function in cardiac surgical patients with preexisting mild-to-moderate renal dysfunction. DESIGN: Prospective, randomized, placebo-controlled, double-blind, clinical study. SETTING: Cardiothoracic anesthesia department at a university hospital. PARTICIPANTS: Adult patients undergoing elective cardiac surgery using cardiopulmonary bypass, with a preoperatively elevated serum creatinine level (n = 24). INTERVENTIONS: Randomized infusions of diltiazem (bolus 0.25 mg/kg followed by a continuous infusion of 1.7 microg/kg/min) (DTZ, n = 12) or placebo (C, n = 12) were started 30 minutes before induction of anesthesia and continued for 24 hours. MEASUREMENTS AND MAIN RESULTS: Median plasma concentrations of diltiazem (DTZ group) were 79 microg/L before cardiopulmonary bypass, 67 microg/L at the end of cardiopulmonary bypass, and 164 microg/L at 24 hours postoperatively. Serum creatinine levels; on postoperative days 1, 3, and 5; and 3 weeks postoperatively were similar between groups. Iohexol clearance did not differ between the groups on day 5 but was higher in the DTZ group than in the placebo group 3 weeks after surgery (median, 51 v 40 mL/min/1.73 m(2); p < 0.05). Urinary N-acetyl-beta-glucosamidase concentrations were similar between the groups during the study but were increased from baseline on days 2 and 4 and 3 weeks postoperatively. CONCLUSION: Diltiazem can be safely used in patients who have mild-to-moderate renal dysfunction and undergo cardiac surgery using cardiopulmonary bypass. Within the limits of this study, the data suggest that addition of prophylactic diltiazem may prevent further glomerular damage resulting from cardiopulmonary bypass and may improve glomerular function 3 weeks after cardiac surgery.     

Renal function and cardiopulmonary bypass in pediatric cardiac surgical patients

We studied prospectively the perioperative changes of renal function in nine children undergoing cardiac surgery with cardiopulmonary bypass (CPB). Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured with inulin and ¹³¹I-hippuran clearances before CPB, during hypo and normothermic CPB, following sternal closure and 1 h postoperatively. Urinary alpha glutathione S-transferase (alpha GS-T) was measured pre- and postoperatively as a marker for tubular cellular damage. Plasma and urine creatinine and electrolytes were measured. Free water, osmolal and creatinine clearances, as well as fractional excretion of sodium (FeNa) and potassium transtubular gradient (TTKG) were calculated. GFR was normal before and after surgery. ERPF was low before and after surgery; it increased significantly immediately after CPB. Filtration fraction (FF) was abnormally elevated before and after surgery; however, a significant decrease during normothermic CPB and sternal closure was found. Alpha GS-T presented a moderate, but nonsignificant increase postoperatively. FeNa also increased in this period, but not significantly. Creatinine, osmolal, free water clearances, as well as TTKG, were normal in all patients pre- and postoperatively. We conclude that there is no evidence of clinically significant deterioration of renal function in children undergoing repair of cardiac lesions under CPB. Minor increases of alpha GS-T in urine postoperatively did not confirm cellular tubular damage. There was no tubular dysfunction at that time.Supported by grant 1030645 from FONDECYT.     

Improvement of renal function in azotaemic hypertensive patients after surgical revascularization

Between 1974 and 1986, 17 patients (16 men and 1 woman) with renal insufficiency (serum creatinine greater than 1.5 mg/dl, mean 3.75 mg/dl), with a mean age of 51.3 years, underwent surgical renal revascularization. Two of them were on maintenance haemodialysis. All were severely hypertensive in spite of antihypertensive drugs. Atherosclerosis was the cause of renal stenosis in 14 cases and fibromuscular dysplasia in 3. Operative procedures included splenorenal shunt (5), autotransplantation (3), aortorenal bypass (3), hepatorenal bypass (1), bilateral renal endarterectomy (1), renal ostial closure (1) and nephrectomy (3). Mean serum creatinine showed a decrease from 3.76 to 1.65 mg/dl (P less than 0.005). Mean arterial pressure dropped from 161 mmHg to 103 mmHg (P less than 0.001). Systolic and diastolic pressures also showed significant decreases. Two patients died. Four patients required a second operation and the renal function and blood pressure then improved. Renovascular disease must be ruled out in patients with renal insufficiency associated with hypertension, including those patients on haemodialysis. We conclude that renal revascularization surgery is a reliable and efficient form of treatment in selected cases of renal failure of renovascular origin.     

Serial changes in body composition in patients with chronic renal failure on peritoneal dialysis]

Nutritional status is one of the most important factors affecting mortality and morbidity in chronic dialysis patients. There are, however, few data on serial body composition changes in these patients. To investigate serial changes in body composition in patients on peritoneal dialysis, we measured intracellular fluid volume(ICF), extracellular fluid volume(ECF), body protein volume(BPV), body fat volume(BFV) and bone mineral content(BMC) using multifrequency bioelectrical impedance analysis (MF-BIA). MF-BIA was performed in 35 patients, consisting of 21 men and 14 women with a mean age of 51.3 +/- 10.9 years, before and after one year of observation. At the baseline in male patients, ICF was 37.0 +/- 3.4%, ECF 19.7 +/- 1.6%, BPV 20.7 +/- 1.7%, BFV 18.1 +/- 6.6% and BMC 4.5 +/- 0.4% of body weight, and in female patients ICF was 34.4 +/- 2.6%, ECF 17.8 +/- 1.9% BPV 19.0 +/- 1.6%, BFV 24.4 +/- 6.2% and BMC 4.5 +/- 0.4% of body weight. In the group of patients whose body weight increased more than 3 kilograms(n = 9), the increase rate of BFV was 32.3 +/- 20.2%, significantly higher than that of the other segments(p < 0.001). On the other hand, in the group of patients whose body weight decreased more than 3 kilograms(n = 5), each segment showed the same extent of decrease and there was no significant difference in the decrease rates among each segment. In the group of patients whose body weight was stable(n = 21), changes in each body composition segment were extremely small. It could be concluded that the body weight increase is due mainly to increase in BFV and body weight decrease results from a concurrent decrease in each body composition segment in peritoneal dialysis patients.     

Assessment of renal function in surgical patients by urine osmolality concentration tests

Evaluation of renal function by urine concentration induced by fluid deprivation (thirteen to fifteen hours) or exogenous ADH (aqueous Pitressin, 10 units intramuscularly) has been carried out in 196 patients. These studies indicate that in comparison with the endogenous creatinine clearance test, the urine osmolality concentration test is simpler, is less subject to error, and appears to be a reliable method of identifying the majority of cases with significant impairment of renal function.A small proportion of patients with elevation of serum creatinine above 1.5 mg per cent may not have diminished concentrating ability; however, a combination of serum creatinine and urine osmolality tests would identify a wide span of renal functional abnormalities.Urine osmolality concentration tests deserve further definitive evaluation and currently are worthy of clinical application for the recognition of disorders of renal function.Under the conditions of an active general surgical ward, estimation of endogenous creatinine clearance is an unreliable measure of renal function.     

Effect of hyperparathyroidism on cardiac function in patients with end-stage renal disease

Heart studies were carried out in 7 patients with end-stage renal disease (ESRD) who underwent parathyroidectomy for secondary hyperparathyroidism. The studies, which included echocardiography and equilibrium radionuclide angiography (ERNA), were performed prior to parathyroidectomy and 2 weeks, 3 months, and 6 months following it, on a nondialytic day. Heart rate decreased from 89.3 +/- 1.3 to 81.4 +/- 1.5 min-1 (p less than 0.001) following parathyroidectomy and returned to the initial level at 3- and 6-month examination. Cardiac output decreased from 3170 +/- 68 to 2943 +/- 57 ml/min (p less than 0.01) following parathyroidectomy and returned to basal level on 3 and 6-month determinations. End-diastolic dimension (EDD), end-systolic dimension (ESD), septal and posterior wall thickness and shortening fraction (SF) as measured by echocardiography were normal prior to parathyroidectomy and remained unchanged following it. Left ventricular ejection fraction (LVEF), end-diastolic and end-systolic volumes measured by ERNA did not change following parathyroidectomy. This study suggests that hyperparathyroidism has little effect on cardiac performance and, except for a short-lived decrease in heart rate and cardiac output, parathyroidectomy does not affect cardiac performance when performed in patients with preoperatively normal cardiac output.     

Sirolimus improves renal function in cardiac transplantation

In kidney and liver transplantation, sirolimus therapy has been shown to be comparable to cyclosporine in a head-to-head comparison, but it results in better preservation of renal reserve. In heart transplantation, information about the use of sirolimus is limited. We present the results of the progressive conversion from cyclosporine to sirolimus in a series of 8 heart transplant patients in whom renal dysfunction developed. The baseline creatinine level was 2.4 +/- 0.5 mg/dL, and plasma levels of cyclosporine were within the therapeutic range. After the introduction of sirolimus, the creatinine level fell within the first month to 1.76 +/- 0.2 mg/dL, or mean decrease of 0.6 +/- 0.25 mg/dL (P < .05). After 3 +/- 2.2 months the improvement continued (1.69 +/- 0.2 mg/dL). In 1 patient sirolimus was withdrawn during the first 24 hours, because of gastric intolerance. No patient developed an opportunist infection, allograft rejection, or important hematologic disorder. We conclude that sirolimus appears to be effective in heart transplant patients to improve renal function.     

Serial change in echocardiographic parameters and cardiac failure in end-stage renal disease

Echocardiographic abnormalities are the rule in patients starting dialysis therapy and are associated with the development of cardiac failure and death. It is unknown, however, whether regression of these abnormalities is associated with an improvement in prognosis. As part of a prospective cohort study with mean follow-up of 41 mo, 227 patients had echocardiography at inception and after 1 yr of dialysis therapy. Improvements in left ventricular (LV) mass index, volume index, and fractional shortening were seen in 48, 48, and 46%, respectively. Ninety patients had developed cardiac failure by 1 yr of dialysis therapy. Twenty-six percent of the remaining 137 patients subsequently developed new-onset cardiac failure. The mean changes in LV mass index were 17 g/m(2) in those who subsequently developed cardiac failure compared with 0 g/m(2) among those who did not (P = 0.05). The corresponding values were -8 versus 0% for fractional shortening (P < 0.0001). The associations between serial change in both LV mass index and fractional shortening and subsequent cardiac failure persisted after adjusting for baseline age, diabetes, ischemic heart disease, and the corresponding baseline echocardiographic parameter. Regression of LV abnormalities is associated with an improved cardiac outcome in dialysis patients. Serial echocardiography adds prognostic information to one performed at baseline.     

The effects of recent aspirin ingestion on platelet function in cardiac surgical patients

OBJECTIVE: To examine the effects of the preoperative aspirin-free interval on platelet function in cardiac surgical patients. DESIGN: Prospective clinical investigation. SETTING: University-affiliated teaching hospital. PARTICIPANTS: Patients undergoing elective coronary artery bypass graft surgery (n = 100). INTERVENTIONS: The patients were divided into 3 groups based on the number of days since they last ingested aspirin: < or =2 days, 3 to 7 days, and >7 days. Preoperative platelet function was assessed in all patients using platelet aggregation responses to arachidonic acid, 5 microg/mL, and Platelet Function Analyser (PFA100) collagen/epinephrine closure times. MEASUREMENTS AND MAIN RESULTS: Patients who ceased aspirin < or =2 days preoperatively had weaker platelet aggregation responses (18.5% +/- 7% maximum aggregation, mean +/- SD, n = 36) than patients who ceased aspirin 3 to 7 days preoperatively (68.8% +/- 29%, n = 48, p < 0.001) or >7 days preoperatively (68.3% +/- 28%, n = 16, p < 0.001). Similarly, patients who ceased aspirin < or =2 days preoperatively had longer PFA100 closure times (168 +/- 52 sec) than patients who ceased aspirin 3 to 7 days preoperatively (122 +/- 43 sec, p < 0.001) or >7 days preoperatively (128 +/- 42 sec, p < 0.01). The percentage of abnormal responses was also greatest in the aspirin < or =2 days group. CONCLUSION: Cardiac surgical patients who ingest aspirin < or =2 days preoperatively have greater impairment of platelet function than patients who have a longer preoperative aspirin-free interval.     

Preservation of renal function with surgical revascularization in patients with atherosclerotic renovascular disease

OBJECTIVE: Clinical and anatomic factors predictive of a favorable response to renal revascularization performed for renal function salvage remain poorly defined. To clarify decision making in such patients we reviewed a contemporary experience of surgical renal artery revascularization (RAR) performed primarily for preservation of renal function. METHODS: Between June 1990 and March 2001 (ensuring 1 year minimum follow-up), 96 patients with renal insufficiency (serum creatinine [Cr] concentration >or=1.5 mg/dL) and hypertension underwent RAR for preservation of renal function. Study end points included early and late renal function response, progression to dialysis dependence, and long-term survival. Variables potentially associated with these end points were assessed with univariate analysis, Cox regression analysis, and logistic regression analysis, and survival was assessed with the Kaplan-Meier method. RESULTS: Perioperative failure of RAR occurred in 3 patients (3%), with perioperative mortality in 4 patients (4.1%); thus 92 patients were available for long-term follow-up (mean, 39 months). Mean patient age was 70 +/- 9 years with a mean baseline Cr of 2.6 mg/dL (range, 1.5-7.8 mg/dL). Operative management consisted of aortorenal bypass in 38% of patients, extraanatomic bypass in 38% of patients, and endarterectomy in 24% of patients; 32% of patients required combined aortic revascularization and RAR, and 27% underwent bilateral RAR. At hospital discharge renal function had improved (20% decrement in Cr) in 41 (43%) patients, including 7 patients who were removed from dialysis; remained unchanged in 40 (41%) patients; and declined (20% increase in Cr) in 15 (16%) patients. At last follow-up renal function was either improved or unchanged in 72% of patients. Predictors of a favorable response to RAR at last follow-up included stable Cr at hospital discharge (odds ratio [OR], 7.1; 95% confidence interval [CI], 2.5-21.8; P =.0004) and decreased Cr at hospital discharge (OR, 16; 95% CI, 1.6-307.8; P <.0001); bilateral renal artery repair (OR, 3.1; 95% CI, 0.9-10.6; P =.07) approached clinical significance. Predictors of worsened excretory function at last follow-up included decline of renal function at hospital discharge (OR, 28.9; 95% CI, 5.0-165.4; P =.0002), intervention to treat unilateral renal artery stenosis (OR, 3.8; 95% CI, 0.8-16.6; P =.05), and level of baseline Cr (OR, 3.0; 95% CI, 1.0-4.0; P =.04). Progression to dialysis occurred in 16 (17%) patients. Dialysis-free survival at 5 years was 50%, and overall actuarial survival at 5 years was 59%. Predictors of progression to dialysis during follow-up included treatment of complete renal artery occlusion (OR, 6.2; 95% CI, 1.3-29.5; P =.02), early failure of RAR (OR, 3.1; 95% CI, 0.7-14.2; P =.04) and baseline Cr (OR, 2.9; 95% CI, 1.3-6.1; P =.006). CONCLUSION: Long-term clinical success in the preservation of renal function, noted in 70% of patients, can be predicted by the initial response to RAR and by anatomic factors, in particular, bilateral repair. While extreme (mean Cr >or=3.2 mg/dL) renal dysfunction generally is predictive of poor long-term outcome, a subset of patients will experience favorable results, even to the extent of rescue from dialysis. These results may facilitate clinical decision making in the application of RAR for renal function salvage.     

Effects of probenecid on renal function in surgical patients anesthetized with low-flow sevoflurane

BACKGROUND: Dehydrofluorination of sevoflurane by carbon dioxide absorbents in anesthesia machines produces compound A, which is nephrotoxic in rats. Several clinical studies indicate that prolonged low-flow sevoflurane anesthesia is associated with an increased urinary excretion of biochemical markers, such as protein. Probenecid, a competitive inhibitor of organic anion transport, diminishes compound A nephrotoxicity in rats. The purpose of the present study was to examine the effects of low- and high-flow sevoflurane anesthesia on urinary excretion of biochemical markers in humans and to examine the effects of probenecid on urinary excretion of these markers. METHODS: Elective surgical patients (n = 64) were assigned to four groups (n = 16 each): low-flow sevoflurane plus probenecid (LSP), low-flow sevoflurane (LS), high-flow sevoflurane plus probenecid (HSP), and high-flow sevoflurane (HS). Probenecid (2.0 g) was administered orally 2 h before the induction of anesthesia in both the LSP and HSP groups. Nothing was administered orally 2 h before the induction of anesthesia in either the LS or HS groups. All patients underwent prolonged low-flow (1 l/min) or high-flow (6 l/min) sevoflurane anesthesia. Urinary excretion of protein, albumin, beta(2)-microglobulin, glucose, and N-acetyl-beta-d-glucosaminidase was measured for up to 7 days postoperatively. RESULTS: Sevoflurane doses were similar in all four groups. There were no differences in blood urea nitrogen, creatinine, or creatinine clearance among the four groups after anesthesia. Average values for urinary excretion of protein, beta(2)-microglobulin, and N-acetyl-beta-d-glucosaminidase in the LS group were significantly higher than those in the other groups (LSP, HSP, HS; P < 0.05). There was no significant difference between the LS and LSP groups in average values for urinary excretion of albumin and glucose, although there were significant differences between the LS and both high-flow sevoflurane groups (HSP, HS). CONCLUSIONS: Low-flow sevoflurane, which produces a sevenfold higher compound A exposure than high-flow sevoflurane, resulted in significant increases of several biochemical markers in half of the patients. Probenecid appears to provide protection against these renal effects.