Chirag R. Parikh

Urinary tract infections after renal transplantation: a retrospective review at two US transplant centers

Abstract:  Urinary tract infections (UTIs) are the most common infectious complication following renal transplantation. Previous studies uniformly report that renal transplant recipients develop UTIs more often than the general population, but widely differ on how frequently UTIs occur after transplantation. These studies also disagree on the risk factors associated with developing post‐transplant UTIs, as well as the effect that UTIs may have on graft outcomes and patient mortality. We performed a retrospective cohort study including all the adult patients who received a renal transplant at two US transplant centers from January 1996 to December 2002 (500 patients). Two hundred and thirteen (43%) patients developed one or more post‐transplant UTIs over a mean follow‐up period of 42 months. Significant risk factors for post‐transplant UTIs were advanced age, female gender, reflux kidney disease, use of azathioprine and cadaveric donor. UTIs did not increase risk for renal graft loss, but were associated with increased mortality (3.5 odds ratio, 95% confidence interval 1.68–7.23). We conclude UTIs may be associated with an increased mortality risk in renal transplant recipients. Prevention of UTIs in high‐risk renal transplant patients or those with recurrent UTIs may possibly decrease post‐transplant mortality.

Kidney Transplantation for Systemic Sclerosis Improves Survival and may Modulate Disease Activity

Systemic sclerosis (SS) may lead to sclerodema renal crisis, an unusual cause of end‐stage renal disease (ESRD) with historically poor hemodialysis outcomes. Little information is available on outcomes after kidney transplantation. Information from the UNOS registry was obtained on SS patients in the United States, listed for kidney transplants between 1985–2002. We compared survival at 1 and 3 years in patients who received cadaveric transplants with patients who remained on the waiting list. Graft survival, cause of graft loss, frequency of early graft loss and pre‐ and post‐transplant skin scores were analyzed. Two hundred and fifty‐eight patients with SS were listed for transplantation. Survival was significantly prolonged in patients receiving transplants (p = 0.005). Graft survival at 1 and 3 years was 68% and 60%. Early graft loss was common. Skin scores improved in all four subjects at our center, with an average decline of 60.7% (p = 0.024). Kidney transplantation confers a survival benefit in ESRD due to SS. Transplantation may be associated with an improvement in systemic manifestations of disease. Despite suboptimal graft survival, kidney transplant should be considered the treatment of choice in ESRD due to SS.

Discrepancies in Serum Albumin Measurements Vary by Dialysis Modality

Background. Serum albumin level is an important prognostic marker in patients with chronic renal failure. However there are discrepancies in the methods of estimation of serum albumin. The objective of this study is to evaluate the magnitude of the discrepancy in the serum albumin levels as measured by Bromcresol Green (BCG) and Bromcresol Purple (BCP) dye methods in patients on hemodialysis (HD) and peritoneal dialysis (PD) and to ascertain the clinical determinants of the discrepancy (ΔSA = BCG-BCP; g/dL) in each of the modalities. Method. We measured serum and plasma albumin levels by BCG and BCP methods in 19 adult HD patients and 18 adult PD patients treated in the dialysis units of the University of Colorado Health Sciences Center. Similar measurements were performed in 10 normal adult subjects. In all groups, paired blood samples were taken to estimate the albumin in both serum and plasma. Nephelometry (NM) was subsequently performed on the serum of 13 of the HD patients, 14 of the PD patients, and each of the 10 normal subjects. Results. We found that for both the dye methods serum and plasma albumin levels are almost identical in each of the three subject groups. In the normal subjects serum albumin estimated by BCP is in good agreement with NM values but BCG overestimates the albumin levels. In the PD group the discrepancy between the BCG and BCP (ΔSA) is statistically significant with the BCG averaging 0.59 ± 0.12 g/dL more than the BCP. The BCG values are closer to those obtained by the “gold standard”, NM. In the HD group the ΔSA is significantly (p<0.001) less than in the PD group (0.34 ± 0.11 g/dL). As for PD, BCG values are closer to NM values. Increasing age, female gender, and higher dialysis adequacy are associated with higher ΔSA in the HD but not in the PD group. Utilizing linear regression analysis we developed equations for each dialysis modality to convert albumin measurements from one method to the other. Conclusion. We confirm that a discrepancy exists between the commonly used dye methods (BCG and BCP) for serum albumin estimation. This discrepancy is significantly lower in HD patients than in PD patients. Nephrologists should be aware of this discrepancy and appropriate corrections should be made during quality improvement analysis.

Reversal of end-stage renal disease after aortic dissection using renal artery stent: a case report

BackgroundMedical management is the conventional treatment for Stanford Type B aortic dissections as surgery is associated with significant morbidity and mortality. The advent of endovascular interventional techniques has revived interest in treating end-organ complications of Type B aortic dissection. We describe a patient who benefited from endovascular repair of renal artery stenosis caused by a dissection flap, which resulted in reversal of his end-stage renal disease (ESRD).Case presentationA 69 y/o male with a Type B aortic dissection diagnosed two months earlier was found to have a serum creatinine of 15.2 mg/dL (1343.7 μmol/L) on routine visit to his primary care physician. An MRA demonstrated a rightward spiraling aortic dissection flap involving the origins of the celiac artery, superior mesenteric artery, and both renal arteries. The right renal artery arose from the false lumen with lack of blood flow to the right kidney. The left renal artery arose from the true lumen, but an intimal dissection flap appeared to be causing an intermittent stenosis of the left renal artery with compromised blood flow to the left kidney. Endovascular reconstruction with of the left renal artery with stent placement was performed. Hemodialysis was successfully discontinued six weeks after stent placement.ConclusionPercutaneous intervention provides a promising alternative for patients with Type B aortic dissections when medical treatment will not improve the likelihood of meaningful recovery and surgery entails too great a risk. Nephrologists should therefore be aggressive in the workup of ischemic renal failure associated with aortic dissection as percutaneous intervention may reverse the effects of renal failure in this population.

UNMEASURED CATIONS: PROBABLE CAUSE OF RELATIVELY LOW ANION GAP IN CHRONIC RENAL FAILURE

It is commonly believed that the electrolyte pattern in the patients with chronic renal failure (CRF) is associated with high anion gap (AG) and low serum bicarbonate (HCO3). However it was seen in many clinical studies that the AG is normal or only minimally increased in such patients. It is also known that organic cations, in particular guanidines, also increase in the serum of patients with CRF. We thus postulated that the relatively small increase in AG could be, in part, explained by the coexistent increase in unmeasured cations. If this is true, one may expect that the serum osmolality measured directly will be higher than the estimated one, leading to an osmolar gap (OG). Previous studies have shown that indeed OG exists in patients with CRF. We proceeded to determine SMA-7, AG, and OG simultaneously in ambulatory, undialyzed CRF patients with serum creatinine between 4 and 12 mg/dL. These investigations were also done on nine patients, after dialysis, who went on to have dialysis. The patients were divided into the normal AG (AG ≤ 14) and a high AG (AG > 14) groups. There was no correlation of serum bicarbonate with degree of renal dysfunction. Serum AG influenced HCO3 only in the patients with high AG group (bicarbonate = 23.85 − 0.69 (ΔAG), r2 = 0.45). In patients with normal anion gap there was a good correlation between ΔAG and OG (ΔAG = 3.4 − 0.15 OG, r = 0.46, r2 = 0.21, p < 0.05). Thus serum bicarbonate appears to be controlled by both AG and OG. Following dialysis, OG decreased from 15.5 ± 1.06 to 6.08 ± 1.71, p < 0.01. We conclude that OG must be made up of unmeasured cations of low molecular weight as it normalizes the AG, and gets cleared after dialysis. These low molecular weight substances could be guanidines, such as guanidosuccinic acid and methylguanidine, which are increased by one hundred fold in CRF.