Venkataraman Ramanathan

Screening asymptomatic diabetic patients for coronary artery disease prior to renal transplantation.

Background. Coronary artery disease (CAD) is a significant contributor to excess mortality in renal transplant candidates with diabetes mellitus (DM). Prior studies relating to risk stratification for significant CAD in diabetics are confined to Caucasian type 1 DM patients. Methods. To assess the prevalence of clinically silent CAD and to identify variables that are associated with CAD, we retrospectively analyzed the cardiac catheterization data of 97 asymptomatic type 1 and 2 DM kidney and kidney-pancreas transplant candidates. Results. Thirty-three percent of type 1 and 48% of type 2 DM patients had significant stenosis (≥70%) in 1 or more coronary arteries. On multivariate logistic regression analysis, body mass index (BMI) >25 was significantly associated with CAD (relative risk = 4.8, P = 0.002). The age of the patient (7% increase in risk/year, P = 0.01; or relative risk = 3.0 if age >47 years, P = 0.032) and smoking history (2% increase in risk/pack-year of smoking, P = 0.10) were also associated with CAD. African American patients, who comprised 30% of the sample, had a 71% lower risk compared with Caucasian patients (P = 0.03). Factors that were not significantly associated with CAD included gender, type of diabetes, and whether dialyzed for >6 months prior to catheterization. Conclusions. We conclude that a notable proportion (approximately one-third to one-half) of asymptomatic type 1 and type 2 diabetic renal transplant candidates have significant CAD. Additionally, young African American DM patients with no smoking history and a BMI ≤25 are at reduced risk, and invasive tests may not be necessary in this group.

Novel H1N1‐associated rhabdomyolysis leading to acute renal failure

The WHO recently declared that the novel influenza H1N1 virus was responsible for the 2009 flu pandemic. As the virus continues to spread globally and affect more individuals, more complications of infection with this virus are being recognized. To our knowledge, we report the first case of H1N1-induced rhabdomyolysis leading to acute renal failure in an adult. This case highlights the importance of recognizing a significant extrapulmonary complication of H1N1 infection.

Characteristics of Biofilm on Tunneled Cuffed Hemodialysis Catheters in the Presence and Absence of Clinical Infection

BACKGROUND Biofilm occurring on the surface of tunneled hemodialysis (HD) catheters is difficult to eradicate and often is associated with recurrent bacteremia. We studied biofilm formation on catheters from patients with and without bacteremia to identify the location of bacterial growth and measure biofilm thickness. STUDY DESIGN Prospective observational study. SETTING & PARTICIPANTS 76 adult HD patients; 26 had HD catheters removed for bacteremia and 50 had catheters removed for reasons other than infection. PREDICTORS Segment of catheter, reason for catheter removal. OUTCOMES & MEASUREMENTS Microbiological growth and biofilm thickness on the outer and luminal surfaces of extravascular and intravascular catheter segments. RESULTS Catheter cultures were positive in 16 (62%) patients with bacteremia and 15 (30%) when the catheter was removed for non-infection-related reasons. In catheters with positive cultures, the outer surface of the extravascular segment was the most common site of bacterial growth (15/16 [94%] and 11/15 [73%] for bacteremic and nonbacteremic patients, respectively). Bacteremic patients had significantly thicker biofilm on all catheter surfaces, and in bacteremic patients, the biofilm was significantly thicker on the outer compared with the luminal surface for both extravascular (14.53 ± 6.17 vs 11.97 ± 5.01 μm; P < 0.001) and intravascular (12.21 ± 5.3 vs 9.46 ± 3.71 μm; P < 0.001) segments. Extravascular segments had significantly thicker biofilm compared with intravascular segments on both the outer (P < 0.001) and luminal (P < 0.001) surfaces. Similarly, in patients for whom the catheter was removed for non-infection-related reasons, the catheter had thicker biofilm on the outer compared with the inner surface in both extravascular (2.19 ± 2.84 vs 1.62 ± 2.33 μm; P < 0.001) and intravascular (1.92 ± 2.62 vs 1.29 ± 2.33 μm; P < 0.001) segments. Similar to catheters from bacteremic patients, the outer and luminal surfaces of the extravascular segments of the catheters had significantly thicker biofilm compared with their corresponding surfaces on the intravascular segments. LIMITATIONS Observational study. CONCLUSIONS The outer surface of the extravascular segment of tunneled dialysis catheters in both bacteremic and nonbacteremic HD patients has the thickest biofilm and highest microbiological yield, and biofilm is thicker in patients with bacteremia. This knowledge is important for designing preventive strategies and also in the management of patients with catheter infection.

Chronic allograft nephropathy and nephrotic range proteinuria

Abstract:  While the association between post‐transplant nephrotic range proteinuria (PTx‐NP) and chronic allograft nephropathy (CAN) has been described, the factors that determine graft survival in such patients are unclear. We retrospectively identified 30 patients with biopsy‐proven CAN who presented with PTX‐NP between 1988 and 2002. Patients were stratified into two groups according to PTX‐NP onset: <1 yr vs. >1 yr post‐transplantation. Both groups were comparable with respect to the degree of renal dysfunction (serum creatinine 4.3 ± 2.5 mg/dL vs. 3.4 ± 1.5 mg/dL) and proteinuria (4.7 ± 1.6 gm/d vs. 5.8 ± 3 gm/d). After a mean follow‐up of 14 months post‐biopsy, 87% of patients had lost their grafts in both groups (89% vs. 83%, p = NS). Overall, patients with serum creatinine ≤2 mg/dL had better graft survival during follow‐up than patients with serum creatinine >2 mg/dL (75% vs. 4%, Fisher Exact Probability p = 0.0038). Using Kaplan–Meier estimate, the 5‐yr graft survival rate was 100% for patients with serum creatinine ≤2 mg/dL and 40% in those with >2 mg/dL (p = 0.06). The magnitude of proteinuria beyond 3 gm/d did not influence graft survival. One‐half of the patients (n = 15) received therapy with angiotensin converting enzyme inhibitors (ACEI). Graft survival, however, was not different between the patients who received ACEI compared with the patients who did not receive ACEI (13% vs. 13%).

Efficacy of trypsin in enhancing assessment of bacterial colonisation of vascular catheters.

Since the number of organisms isolated from a medical device is crucial in assessing the likelihood of device-associated infection, we examined whether incubation of catheters in trypsin before sonication can increase the yield of superficially colonised vascular catheters in vitro and those removed from patients. Polyurethane and silicone catheters were individually colonised in vitro with individual clinical isolates including Staphylococcus aureus and Escherichia coli. Equal numbers of 1 cm segments of colonised catheters were then individually incubated either in a trypsin-containing solution or a control solution without trypsin. Each solution containing the segment was then sonicated and cultured quantitatively. In the clinical arm, indwelling catheters removed from patients were also cut into 1 cm segments that were equally suspended in the trypsin-containing or control solution and then sonicated and cultured quantitatively. Trypsin-based sonication enhanced the detection of S. aureus on colonised polyurethane and silicone catheters in vitro by 14- and 30-fold, respectively (P = 0.03 and P = 0.04), and the detection of E. coli on colonised polyurethane and silicone catheters by 3- and 6-fold, respectively (P = 0.04 and P = 0.05). Compared with sonication alone, trypsin followed by sonication resulted in 10% increase in the detectability of significant colonisation of indwelling catheters removed from patients and 11% increase in the mean colony counts of colonising organisms (P = 0.04). Exposure of catheters to trypsin before sonication improves the sensitivity of sonication and enhances the accuracy of assessing significant catheter colonisation.

Acute Renal Failure After Liposuction

Because the first liposuction surgery performed in Italy in 1974, this therapy has been refined and developed into a cosmetic procedure with rare complications. Tumescent liposuction and various generations of ultrasound-assisted lipoplasty are currently available. In addition to the local complications such as bruising, swelling, pain, and temporary numbness at the surgical site, systemic complications such as sepsis, fat embolism, – 7] and visceral perforations have been occasionally reported. Even though studies have failed to demonstrate changes in central venous pressure after large-volume fat aspirations in young healthy patients, liposuction may be associated with hypotension and intravascular volume contraction. In these patients, the hemodynamic imbalance is usually offset by intense volume resuscitation. To our knowledge, there has been only a single report of acute renal failure (ARF) after liposuction that was attributed to acute tubular necrosis from excessive bleeding. We report an unusual cause of ARF that was possibly precipitated by the hemodynamic alterations after liposuction.

Belatacept conversion in an HIV‐positive kidney transplant recipient following anti‐thymocyte globulin induction

Herein, we describe a case of early belatacept conversion in a human immunodeficiency virus (HIV)‐positive kidney transplant recipient in an effort to improve suboptimal graft function and avoid drug interactions following anti‐thymocyte globulin (ATG) administration. We observed improvement in renal function without HIV disease progression or opportunistic infections. Donor‐specific antibodies appeared shortly after conversion but cleared without intervention. This case highlights belatacept as a means to improve renal function and avoid significant drug interactions even following ATG induction.