Mufaddal Kheda

Influence of arterial elasticity and vessel dilatation on arteriovenous fistula maturation: a prospective cohort study

BACKGROUND Arteriovenous fistula maturation requires dilatation of the anastomosed artery and vein. The factors that affect dilatation and the mechanisms by which dilatation promotes maturation are not understood. This pilot study tested two hypotheses: that low arterial elasticity is associated with maturation failure, and that vessel dilatation is required for adequate fistula blood flow during dialysis. METHODS Thirty-two patients underwent preoperative measurement of small artery elasticity index, and pre-anastomosis measurement of artery and vein luminal diameters during fistula surgery. Fistulas were considered mature if they were used successfully in three consecutive treatments within 6 months. A mathematical model was used to determine whether vessel dilatation is needed for adequate fistula flow. RESULTS Six fistulas were excluded from analysis of maturation because dialysis did not begin within 6 months. Twenty-one of the remaining 26 fistulas were located in the upper arm. Six of 26 failed to mature, and all 6 developed stenosis. The average small artery elasticity index was lower in failed than in matured fistulas (2.25 versus 3.71 ml/ mmHg x 100, P = 0.02). Artery and vein diameters of the 32 patients ranged from 2.5 to 5.0 and 3.5 to 7.0 mm, respectively. When the diameters were applied to the mathematical model, predicted fistula flows ranged from 412 to 1380 ml/min. CONCLUSIONS Low arterial elasticity is associated with stenosis and fistula maturation failure. However, vessel dilatation is not needed for adequate blood flow except at the smaller diameters in this study. We speculate that low elasticity promotes development of stenosis. Larger studies are needed to confirm these promising results and to determine whether therapies directed at improving elasticity can improve maturation.

Cardiac implantable electronic device infection in patients with end-stage renal disease

INTRODUCTION Cardiac implantable electronic devices (CIED) are increasingly being used in end-stage renal disease (ESRD) patients. These patients have a high risk of device infection. OBJECTIVES To study the optimal management of device infections in patients with ESRD. METHOD We used the United States Renal Data System (USRDS) to assess the presence of a CIED and associated comorbidities, risk factors for infection, and mortality following device extraction or medical management in ESRD patients with CIED infection. Univariable, multivariable, and survival analyses were performed using USRDS data from 2005 to 2009. RESULTS Of 546,769 patients, 6.4% had CIED and 8.0% of those developed CIED infection. The major risk factors for device infection were black race, temporary dialysis catheter, and body mass index >25. Patients with artificial valves were excluded from the analysis. Only 28.4% of infected CIED were removed. CIED removal was more common in those with congestive heart failure. The median time to death following diagnosis of a CIED infection was 15.7 months versus 9.2 months for those treated via device extraction versus medical-only therapy (hazard ratio: 0.75; 95% confidence interval: 0.68-0.82). CONCLUSION Patients with ESRD and infected CIEDs have a poor prognosis. Rates of device extraction are low, but this strategy appears to be associated with modest improvement in survival.

Bacteremia in Hemodialysis Patients With Hepatitis C

Background:Hepatitis C virus (HCV) infection and bacteremia are common comorbidities in hemodialysis patients. A specific relationship between HCV infection and bacteremia has not been defined; however, there is evidence of immune compromise in both HCV-infected and uremic patients, suggesting that this group may be at higher risk for infection. Methods:We investigated risk factors and mortality associated with bacteremia in HCV-infected hemodialysis patients from the United States Renal Data System. Results:During the 4-year study period, HCV was present in 2.1% of 355,084 patients initiating hemodialysis. When compared with the total population, the rate of bacteremia was significantly higher in patients with HCV (38.3% versus 21.8%). The adjusted relative risk (RR) for bacteremia was higher in HCV versus all patients (relative risk, 95% confidence interval [CI]) in the presence of methicillin-resistant Staphylococcus aureus infection (2.64, CI: 2.58–2.70 versus 2.32, CI: 2.27–2.38), HIV (1.93, CI: 1.85–2.02 versus 1.86, CI: 1.77–1.95) urinary tract infection (1.79, CI: 1.77, 1.82 versus 1.64, CI: 1.61–1.67) and cirrhosis (1.49, CI: 1.45–1.54 versus 1.29, CI: 1.25–1.34). The hazard ratio (95% CI) for death was higher in HCV versus all patients at 1.69 (CI: 1.58–1.81) versus 1.54 (CI: 1.53–1.56). Conclusions:These data indicate that several clinical covariates increase the risk of bacteremia in hemodialysis patients, with the magnitude of that risk being further increased by HCV infection. Improving outcomes in HCV-infected hemodialysis patients will likely be dependent on aggressive diagnosis and treatment of both HCV and bacteremia.

Two cases of iodixanol-induced pancreatitis

Because of the escalating number of patients on dialysis and the increased use of vascular access surveillance, more and more hemodialysis patients are undergoing angiographic procedures for angioplasty and thrombectomy of their vascular access. Such procedures expose these patients to radiographic contrast agents (RCAs). Even though, newer low-osmolar and iso-osmolar nonionic RCAs, which are associated with fewer adverse effects, are increasingly used, these agents can still cause complications. We report two cases of pancreatitis in end-stage renal disease (ESRD) patients, associated with intravenous use of the iodixanol. Although RCAs have been reported to exacerbate experimentally induced pancreatitis in animals [1] and possibly prolong the clinical course of acute pancreatitis in humans [3,4], there are no documented cases of intravascular RCA inducing pancreatitis in humans. In the cases below, the RCAs used are iodixanol-320 (iso-osmolar, nonionic dimer with iodine concentration 320 mg/ml) and iohexol-300 (low-osmolar nonionic monomer with iodine concentration 300 mg/ml). The amount of RCA used during the angiogram and thrombectomy of a dialysis access is between 90 and 110 cc per study. The amount of RCA used for the contrast-enhanced computed tomography (CECT) is 140–150 cc per study.

Is Dietary Protein Intake Predictive of 1-Year Mortality in Dialysis Patients?

Background: High mortality in dialysis patients may be associated with protein‐energy wasting (PEW) syndrome characterized by progressively depleted protein and energy stores. While early diagnosis and treatment of PEW can reduce mortality, clinically practical measures for its detection are lacking. Poor dietary protein intake (DPI) is associated with risk of malnutrition and PEW. However, the impact of DPI on mortality is unclear. The purpose of this study is to examine the ability of DPI to predict 1‐year mortality in dialysis patients. Methods: This prospective, secondary study using data from the Comprehensive Dialysis Study and United States Renal Data System examined risk factors associated with 1‐year mortality in dialysis patients. Results: Seventeen (7.5%) of the 227 subjects died within 1 year following baseline data collection. One year survivors were significantly younger (60 ± 13.6 versus 71 ± 12.8; P = 0.0043), had a lower Charlson Comorbidity Index score (1.6 ± 2.3 versus 4.0 ± 3.6; P = 0.0157), higher serum albumin level (3.5 ± 0.5 versus 3.3 ± 0.4; P = 0.0173) and had higher DPI (63 ± 33.7 versus 49.5 ± 21.5 g/day; P = 0.0386) than those who died. In multivariable Cox proportional hazards model analyses, only the Charlson Comorbidity Index adjusted hazard ratio for death (1.24) was significantly associated with increased mortality. The Comprehensive Dialysis Study data showed no association between DPI and 1‐year mortality in dialysis patients. Conclusions: Future studies using more precise measures should further examine the impact of DPI on mortality given the known association of DPI with PEW syndrome and the definitive link between PEW syndrome and survival in dialysis patients.

Mortality risk after herpes zoster infection in end-stage renal disease patients

Abstract Background End-stage renal disease (ESRD) patients have increased risk of developing herpes zoster (zoster) compared with the general population, but mortality risk is unknown. We assessed the risk of mortality in hospitalized ESRD patients with a diagnosis of zoster from the inpatient hospital files (as opposed to outpatient records) of the United States Renal Data System. Methods This study analyzed incident ESRD patients from 2006 to 2009. Based on an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code of zoster infection, we determined 2-year mortality following an inpatient diagnosis. Cox proportional hazards models were used to examine the association of mortality and zoster, when controlling for demographic and other clinical risk factors. Results Zoster was diagnosed in 2784 patients, 51% of whom died within 2 years, with a mean time to death of 8.1 months. Patients who died were more likely to be white and older, score higher on the Charlson Comorbidity Index (CCI) and have other clinical diagnoses besides CCI. Increased risk of death within 2 years was associated with older age (adjusted hazard ratio 1.03), malnutrition (1.31), bacteremia/septicemia (1.16) and increasing CCI (1.10). Zoster vaccine was administered to 27 patients, but the small number precluded analysis of its impact. Conclusions Mortality in ESRD patients with an inpatient zoster diagnosis is increased with older age and higher severity of clinical comorbidities. The role of zoster vaccination on mortality in this population remains to be defined.

Clostridium difficile infection in dialysis patients

Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea. Patients with end-stage renal disease (ESRD) may be at increased risk for CDI. Patients with ESRD with CDI have increased mortality, longer length of stay, and higher costs. The present studies extend these observations and address associated comorbidities, incidence of recurrence, and risk factors for mortality. We queried the United States Renal Data System (USRDS) for patients with ESRD diagnosed with CDI, and assessed for the incidence of infection, comorbidities, and mortality. The records of 419,875 incident dialysis patients from 2005 to 2008 were reviewed. 4.25% had a diagnosis of a first CDI. In the majority of patients with CDI positive, a hospitalization or ICU stay was documented within 90 days prior to the diagnosis of CDI. The greatest adjusted relative risk (aRR) of CDI was present in patients with HIV (aRR 2.68), age ≥65 years (aRR 1.76), and bacteremia (aRR 1.74). The adjusted HR (aHR) for death was 1.80 in patients with CDI. The comorbidities demonstrating the greatest risk for death in dialysis patients with CDI included age ≥65 years and cirrhosis (aHR 2.28 and 1.76, respectively). Recurrent CDI occurred in 23.6%, was more common in Caucasians, and in those who were older. CDI is a common occurrence in patients with ESRD, with elderly patients, patients with HIV positive, and bacteremic patients at highest risk for infection. Patients with CDI had nearly a twofold increased risk of death.

RISK STRATIFICATION SCORING PREDICTS MORTALITY IN DIALYSIS PATIENTS WITH ATRIAL FIBRILLATION

The CHA2DS2VASc score predicts stroke occurrence and mortality in atrial fibrillation (AF) patients. AF and End Stage Renal Disease (ESRD) share many risk factors including heart failure, hypertension, and diabetes. Patients with ESRD and AF may exhibit some or all of these risk factors, suggesting