Steven J. Schwab

Serum β-2 Microglobulin Levels Predict Mortality in Dialysis Patients: Results of the HEMO Study

In the randomized Hemodialysis (HEMO) Study, chronic high-flux dialysis, as defined by higher beta-2 microglobulin (beta(2)M) clearance, compared with low-flux dialysis did not significantly alter all-cause mortality in the entire cohort but was associated with lower mortality in long-term dialysis patients. This analysis examined the determinants of serum beta(2)M levels and the associations of serum beta(2)M levels or dialyzer beta(2)M clearance with mortality. In a multivariable regression model that examined 1704 patients, baseline residual kidney urea clearance and dialyzer beta(2)M clearance were strong predictors of predialysis serum beta(2)M levels at 1 mo of follow-up, with regression coefficients of -7.21 (+/-0.69 SE) mg/L per ml/min per 35 L urea volume (P < 0.0001) and -1.94 (+/-0.30) mg/L per ml/min (P < 0.0001),respectively. In addition, black race and baseline years on dialysis correlated positively whereas age, diabetes, serum albumin, and body mass index correlated negatively with serum beta(2)M levels (P < 0.05). In time-dependent Cox regression models, mean cumulative predialysis serum beta(2)M levels but not dialyzer beta(2)M clearance were associated with all-cause mortality (relative risk = 1.11 per 10-mg/L increase in beta(2)M level; 95% confidence interval 1.05 to 1.19; P = 0.001), after adjustment for residual kidney urea clearance and number of prestudy years on dialysis. This association is supportive of the potential value of beta(2)M as a marker to guide chronic hemodialysis therapy.

Results of Valve Replacement With Mechanical and Biological Prostheses in Chronic Renal Dialysis Patients

BACKGROUND Whether biological or mechanical valves should be used in patients on chronic dialysis therapy remains to be clearly defined. METHODS A retrospective review was performed on 19 consecutive patients from our institution with end-stage renal disease on chronic peritoneal or hemodialysis undergoing aortic (n = 12), mitral (n = 5), or aortic-mitral (n = 2) valve replacement. RESULTS The 9 biological and 10 mechanical valve patients had similar ages (56.5 versus 56.6 years) and cardiovascular risk factors. The overall estimated Kaplan-Meier survival was 60% +/- 12% at 12 months and 42% +/- 14% at 60 months. Mechanical valve patients had a significantly higher rate of postoperative cerebrovascular accidents or bleeding complications (10/10 versus 0/9; chi 2 = 17.0; p < 0.001). No subsequent reoperations were required for biological valve failure at a mean follow-up of 32 +/- 53 months. CONCLUSIONS These results demonstrate that in patients with end-stage renal disease, use of mechanical valves is associated with significant risk of complications, whereas biological valve failure from prosthetic dysfunction is unusual. Overall survival is poor in both groups of patients. Therefore, preference should be given to biological valve instead of mechanical valve prostheses in patients on chronic renal dialysis.

Povidone-Iodine sclerosis of pelvic lymphoceles: A prospective study

Twelve patients presented for percutaneous catheter drainage of 13 postoperative pelvic lymphoceles. Six patients with 7 lymphoceles were treated with povidone-iodine sclerosis prior to catheter removal. Only 1 lymphocele (which continued to drain large amounts of fluid during and after the sclerosis procedure) recurred. Six patients with 6 lymphoceles had their percutaneous catheters removed without sclerosis. Fluid collections recurred in 3 instances, necessitating repeat percutaneous drainage (2 patients) or surgery (1 patient). Percutaneous therapy is the treatment of choice for patients with postoperative lymphoceles. Povidoneiodine sclerosis is often effective in preventing reaccumulation of fluid once the lymphocele cavity is collapsed.

Percutaneous Drainage of Pelvic Lymphatic Fluid Collections in the Renal Transplant Patient

Seventeen renal transplant patients with pelvic lymphatic fluid collections were treated with percutaneous drainage. Eleven of 16 patients with lymphoceles (69%) were successfully managed without surgery, although seven of these patients required repeat catheter insertions, and three patients developed local infections. The patient with an ovarian cystadenoma was treated with surgery. The mean duration of catheter insertion was ten days for initial drainage and 16 days for repeat drainage. Elevated serum creatinines decreased in 14 of the patients with lymphoceles (88%), including all five patients without pelvocaliectasis, but never returned to baseline in six instances. This observation may reflect the inadequate therapy of frequently encountered concurrent renal parenchymal abnormalities (rejection, cyclosporine toxicity, acute tubular necrosis). While percutaneous management of lymphoceles is technically easy and usually ultimately effective, the interventional radiologist should be prepared for long duration of catheter insertions, repeat interventions, and variable clinical courses. Differentiation of lymphoceles from other fluid collections, such as cystic ovarian neoplasms, may be difficult.

Comparison of cardiovascular and renal toxicity after cardiac catheterization using a nonionic versus ionic radiographic contrast agent

Abstract Both ionic and nonionic contrast agents used in angiography are relatively well tolerated but have a number of undesirable effects, particularly on the cardiovascular system and the kidney. 1–7 Whereas low osmolar agents may reduce acute events, contrast nephropathy remains a common cause of in-hospital renal injury, and the potential advantage of one contrast agent over another is less well defined. 2,3 The best method of evaluating the relative toxicity of iopamidol and diatrizoate is by a randomized controlled clinical trial. In principle, there are 2 major designs for a randomized trial: (1) a cohort trial that compares results between different patients, and (2) a crossover trial that compares results within the same patient. The crossover design provides the greatest assurance that between-patient differences will not affect the results, and this design is generally well suited for investigations of pharmaceuticals. As part of a randomized trial using a cohort design, 1,2 we prospectively designed a crossover protocol so that any patient randomized in the trial would receive the alternative contrast agent if a second coronary angiogram proved to be clinically indicated within the study period. In all, 67 of the 443 randomized patients had a second procedure, 41 of whom received the alternative agent. This report summarizes the results of 41 randomized patients in this prospective controlled crossover investigation.

Efficacy and Safety Results with the LifeSite Hemodialysis Access System versus the Tesio-Cath Hemodialysis Catheter at 12 Months

PURPOSE To compare the performance and safety of a fully subcutaneous vascular access device, the LifeSite hemodialysis access system, versus a tunneled hemodialysis catheter, the Tesio-Cath, at 1 year after implantation. MATERIALS AND METHODS Sixty-eight patients who required hemodialysis received implantation of the LifeSite device or a Tesio-Cath device as a part of this multicenter study. Thirty-four patients were treated in each group. The endpoints observed included blood flow rates and associated venous pressures, overall and device-related adverse events, the need for thrombolytic infusions, device-related infections (DRIs) and associated hospitalizations, and technical device survival. RESULTS During the 12-month observation period, significantly higher venous pressures were required in patients with the Tesio-Cath to achieve blood flow rates comparable with those achieved with the LifeSite device. Patients in the LifeSite group experienced a significantly lower rate of non-device-related adverse events (P < .001), device-related adverse events (P < .016), need for thrombolytic infusions (P < .002), and DRIs (P < .013) compared with patients in the Tesio-Cath group. There was a trend toward a lower number of hospital days per month for DRIs in the LifeSite group, with the rate for the Tesio-Cath group being twice that in the LifeSite group. The use of the LifeSite device was also associated with a significantly higher probability of device survival for 12 months after censoring for planned removals (P < .031). CONCLUSIONS The results of the present study demonstrate superior device performance and technical device survival, reduced complications, and the need for fewer interventions with the LifeSite hemodialysis access system compared with a standard hemodialysis catheter during a 1-year time period after implantation.

Survival in Renal Vascular Disease

Renal artery stenosis (RAS) is a relatively uncommon but important potentially reversible cause of renal failure. Little is known about the natural history of ischemic renal disease secondary to RAS. In previous reports, these researchers examined the incidence and risk factors associated with RAS. The study presented here investigates the long-term follow-up of these patients, specifically the effect of RAS on 4-yr, all-cause mortality in a group of 1235 patients undergoing diagnostic cardiac catheterization and abdominal aortography. A total of 1235 consecutive patients undergoing cardiac catheterization also underwent an abdominal flush aortogram. Significant RAS was considered present if one or more renal artery had 50% or greater narrowing in luminal diameter. Four-year unadjusted survival for patients with RAS was 65% compared with 86% for patients undergoing catheterization without significant RAS. Factors associated with decreased 4-yr survival included increased age, increased serum creatinine, presence of RAS, peripheral vascular disease, congestive heart failure, diabetes, hypertension, and reduced ejection fraction. Using the Cox proportional hazards model, the factors associated with decreased 4-yr survival were the presence of significant RAS, reduced ejection fraction, elevated serum creatinine, and symptoms of congestive heart failure. These observations indicate that the presence of significant RAS is a strong independent predictor of 4-yr survival in this patient population.