Stroke and kidney transplantation.

PURPOSE OF REVIEW: This review will focus on the epidemiological data, risk factors, and management of stroke before and after kidney transplant. Stroke is highly prevalent in waitlisted patients as well as kidney transplant recipients and is associated with impaired transplant outcomes. Multiple traditional, nontraditional, and transplanted risk factors increase the risk of stroke. RECENT FINDINGS: Although the risk of stroke is reduced after kidney transplantation compared with remaining on dialysis, the morbidity and mortality from stroke after transplantation remain significant. SUMMARY: Early screening for risk factors before and after a kidney transplant and following the Kidney Disease Improving Global Outcomes (KDIGO) management guidelines could minimize the incidence of stroke and transplant outcomes.

End-stage renal disease patients undergoing angioplasty and bypass for critical limb ischemia have worse outcomes compared to non-ESRD patients: Systematic review and meta-analysis.

BACKGROUND: End-stage renal disease (ESRD) is associated with increased morbidity and mortality following lower extremity amputation for critical limb ischemia (CLI). Angioplasty and bypass are used in ESRD patients with CLI; however, the treatment of choice remains controversial. We compared the long-term outcomes in patients with CLI undergoing angioplasty or bypass to evaluate the differences between patients with ESRD and those without ESRD. METHODS: Established databases were searched for observational studies comparing outcomes following bypass or angioplasty for CLI in patients with ESRD to those in non-ESRD patients. End points included survival, limb salvage, amputation-free survival (AFS), and primary and secondary patency at 1-year post-procedure. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random effect model. RESULTS: We included 20 studies with a total of 24,851 patients. ESRD patients compared to non-ESRD patients with CLI had significantly lower survival post-angioplasty (OR 0.51, 95% CI 0.36-0.72, p < .001) and post-bypass (OR 0.26, 95% CI 0.15-0.45, p < .001). ESRD patients had lower rates of limb salvage post-bypass (OR 0.33, 95% CI 0.21-0.53, p < .001) and post-angioplasty (OR 0.54, 95% CI 0.41-0.70, p < .001). AFS was significantly lower in ESRD patients compared to non-ESRD patients following angioplasty (OR 0.48, 95% CI 0.32-0.71, p < .001) and bypass (OR 0.28, 95% CI 0.16-0.47, p < .001) despite no significant differences in primary patency. ESRD patients had overall worse secondary patency post-angioplasty and/or bypass (OR 0.54, 95% CI 0.32-0.94, p = .03) compared to non-ESRD patients. A meta-analysis of four studies directly comparing survival in ESRD patients with CLI based on whether they underwent angioplasty or bypass showed no difference (OR 0.93, 95% CI 0.64-1.35, p = .69). CONCLUSION: ESRD patients have worse survival, limb salvage, and AFS outcomes following angioplasty and bypass for CLI compared to non-ESRD patients. Large randomized controlled trials comparing these two modalities of treatment in this patient population are needed for further clarity.

Associations between calf, thigh, and arm circumference and cardiovascular and all-cause mortality in NHANES 1999-2004.

BACKGROUND AND AIMS: Prior studies have described an association between calf circumference and cardiovascular disorders. We evaluated the associations between calf, thigh, and arm circumference and cardiovascular and all-cause mortality. METHODS AND RESULTS: We performed a retrospective cohort study of 11,871 patients in the 1999-2004 National Health and Nutrition Examination Survey (NHANES) to determine the association between calf circumference and cardiovascular and all-cause mortality using univariate and multivariate Cox proportional hazards. We additionally examined the association between thigh and arm circumference and mortality. In the multivariable Cox regression for the female stratum, each centimeter increase in calf circumference was associated with a hazard ratio of 0.88 (95% CI 0.84-0.92), and a hazard ratio of 0.90 (95% CI 0.85-0.95) for cardiovascular death. In the model with males, the hazard ratio for higher calf circumference was 0.92 (95% CI 0.88-0.96) for all-cause mortality and 0.94 (95% CI 0.89-0.99) for cardiovascular death. There was a statistically significant association between higher thigh circumference and lower risk of all-cause and cardiovascular mortality. Arm circumference was not similarly associated with mortality in the multivariate model. CONCLUSION: Calf and thigh circumference may provide important prognostic information regarding cardiovascular and all-cause mortality. Future prospective studies should examine the role of extremity circumference and cardiovascular events.

To ligate or not to ligate hemodialysis arteriovenous fistulas in kidney transplant patients.

There is significant disagreement about maintenance or ligation of arteriovenous fistulas (AVFs) in kidney transplant patients (KTPs). Potential harms from maintaining AVFs are their impact on cardiac function, cosmetic concerns and complications such as bleeding and rupture. High flow AVFs can place a strain on the heart and cause or exacerbate pre-existing cardiac dysfunction. There is an improvement in cardiac function after kidney transplantation independent of vascular access status. Studies comparing cardiac parameters in patients with and without AVFs after renal transplantation have shown conflicting results. Ligation of high flow AVFs in KTPs resulted in improvement in cardiac function and prevention of heart failure. In KTPs with deteriorating renal function and high flow AVFs, banding of the AVFs to reduce flow is an option. Patients who retain AVFs after renal transplant have the advantage of immediate, optimal access should the transplant fail and may have preserved kidney function. The patient's post-transplant kidney function, risk factors for transplant loss, AVF blood flow, and cardiac function play an important role when making the decision to ligate or preserve AVFs.

Physical examination of the hemodialysis arteriovenous fistula to detect early dysfunction.

The maintenance of vascular access patency for end-stage renal disease patients on hemodialysis is necessary for survival. Many nephrologists, nurse practitioners, and nurses have limited experience with the physical examination of the arteriovenous fistula. In this review, we define key terms used in the assessment of an arteriovenous fistula. We discuss the arteriovenous fistula physical exam, including details of inspection, palpation, and auscultation. Using these concepts, we review the abnormal findings that can assist practitioners in determining the location of a stenosis. We review the existing literature that validates physical exam findings with gold standard tests such as ultrasound and angiography. Finally, we review data supporting the value of training physicians and nurses in arteriovenous fistula physical examination.

Predialysis volume overload and patient-reported sleep duration and quality in patients receiving hemodialysis.

INTRODUCTION: Previous studies of patients with end-stage renal disease have examined the role of fluid shifts on apnea-hypopnea episodes, but the association between volume overload and patient-reported sleep quality or duration has not been well-established. METHODS: We studied the association between predialysis bioimpedance spectroscopy-derived volume estimates and self-reported sleep quality and duration in 638 patients in the United States Renal Data System ACTIVE/ADIPOSE study receiving hemodialysis from 2009 to 2011. We used questionnaires to assess self-reported sleep duration and quality. We used relative hydration status (fluid overload/extracellular water; FO/ECW) as the primary predictor and examined associations with hours of sleep duration using linear regression. We used multivariable ordinal logistic regression to determine the association between categories of relative hydration status (normal hydration [FO/ECW < 6.8%], mild overhydration [FO/ECW 6.8%-15%], and hyperhydration [FO/ECW > 15%]) and four levels of difficulty with falling asleep, waking, and returning to sleep. FINDINGS: Higher relative hydration status was associated with fewer hours of sleep (-0.31 hours per 10%, 95% confidence interval (CI) -0.49 to -0.13). Compared to the normal hydration group, there was a statistically significant association between higher relative hydration status category and more frequent nighttime waking (OR: mild overhydration 1.92 [95% CI 1.23-2.99], hyperhydration 1.87 [95% CI 1.16-2.99]), a trend toward more difficulty returning to sleep (OR: mild overhydration 1.46 [95% CI 0.94-2.27], hyperhydration 1.52 [95% CI 0.95-2.43]), and no association between relative hydration category and difficulty falling asleep. DISCUSSION: Hydration status was associated with self-reported sleep duration in patients on dialysis. Future studies should prospectively examine the effects of optimizing fluid status on sleep duration and quality.

Estimated pulmonary artery systolic pressure and self-reported physical function in patients on hemodialysis.

BACKGROUND/AIMS: Patients on chronic hemodialysis have a high prevalence of heart disease and poor self-reported physical function. The association between structural heart disease and self-reported physical function in patients on hemodialysis is unknown. METHODS: We studied the association between elevated pulmonary artery systolic pressure (PASP) and self-reported physical function in ESRD in 253 patients in the USRDS ACTIVE/ADIPOSE study between 2009 and 2011. We used multivariate linear regression with PASP obtained from clinical echocardiogram reports as the primary predictor and the Physical Function (PF) subscale of the SF-36 as the primary outcome. To determine whether associations between PASP and PF were driven by fluid overload or left ventricular hypertrophy, we assessed whether PASP was associated with bioimpedance spectroscopy (BIS)-derived extracellular water (ECW) and with left ventricular posterior wall thickness. RESULTS: In a multivariable model, each 10 mm Hg higher PASP was associated with a 3.32-point lower PF score (95% CI -5.95, -0.68). In a multivariable model that included BIS estimates, both left ventricular posterior wall thickness (LVPW, per 5 mm) and ECW were associated with a higher PASP (LVPW 4.21 mm Hg, 95% 0.38-8.04; ECW 1.12 mm Hg per liter, 95% CI 0.07-2.18). Higher LVPW and ECW were independently associated with a lower PF score. CONCLUSION: Left ventricular hypertrophy and elevated pulmonary pressure are associated with worse self-reported physical function in patients on hemodialysis. The role of chronic volume overload on PASP and PF score should be evaluated in a prospective manner.

Association of bioimpedance spectroscopy-based volume estimation with postdialysis hypotension in patients receiving hemodialysis.

Clinical examination to determine the dry weight of patients on hemodialysis (HD) has been problematic, with studies showing discordance between physician assessment and objective measures of volume status.We studied the association between predialysis bioimpedance spectroscopy (BIS)-based estimates of fluid overload and postdialysis hypotension in 635 patients in the United States Renal Data System ACTIVE/ADIPOSE (A Cohort study To Investigate the Value of Exercise/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESRD) study receiving HD in 2009-2011. We recorded predialysis and postdialysis weight and blood pressures over 3 consecutive HD sessions and performed BIS before a single session. Using a previously reported method of estimating normohydration weight, we estimated postdialysis fluid overload (FOpost ) in liters. We used logistic regression with extracellular water/total body water (ECW/TBW) or estimated FOpost as the primary predictor and 1 or more postdialysis systolic blood pressures less than 110 mmHg as the dependent variable. Models were adjusted for age, sex, race, ultrafiltration rate per kilogram of body weight, end-stage renal disease vintage, diabetes mellitus, heart failure, and albumin. Higher ECW/TBW was associated with lower odds of postdialysis hypotension (odds ratio [OR] 0.35, 95% confidence interval [CI] 0.15-0.84 per 0.1, P = 0.02). Every liter of FOpost was associated with lower adjusted odds of postdialysis hypotension (OR 0.86, 95% CI 0.79-0.95, P = 0.003). Prospective studies are needed to determine whether this application of BIS could improve current clinical efforts to minimize episodes of postdialysis hypotension without leading to volume overload.

Association of physical function with predialysis blood pressure in patients on hemodialysis.

BACKGROUND: New information from various clinical settings suggests that tight blood pressure control may not reduce mortality and may be associated with more side effects. METHODS: We performed cross-sectional multivariable ordered logistic regression to examine the association between predialysis blood pressure and the short physical performance battery (SPPB) in a cohort of 749 prevalent hemodialysis patients in the San Francisco and Atlanta areas recruited from July 2009 to August 2011 to study the relationship between systolic blood pressure and objective measures of physical function. Mean blood pressure for three hemodialysis sessions was analyzed in the following categories: <110 mmHg, 110-129 mmHg (reference), 130-159 mmHg, and ≥160 mmHg. SPPB includes three components: timed repeated chair stands, timed 15-ft walk, and balance tests. SPPB was categorized into ordinal groups (≤6, 7-9, 10-12) based on prior literature. RESULTS: Patients with blood pressure 130-159 mmHg had lower odds (OR 0.57, 95% CI 0.35-0.93) of scoring in a lower SPPB category than those whose blood pressure was between 110 and 129 mmHg, while those with blood pressure≥160 mmHg had 0.56 times odds (95% CI 0.33-0.94) of scoring in a lower category when compared with blood pressure 110-129 mmHg. When individual components were examined, blood pressure was significantly associated with chair stand (130-159 mmHg: OR 0.59, 95% CI 0.38-0.92) and gait speed (≥160 mmHg: OR 0.59, 95% CI 0.35-0.98). Blood pressure≥160 mmHg was not associated with substantially higher SPPB score compared with 130-159 mmHg. CONCLUSIONS: Patients with systolic blood pressure at or above 130 mmHg had better physical performance than patients with lower blood pressure in the normotensive range. The risk-benefit tradeoff of aggressive blood pressure control, particularly in low-functioning patients, should be reexamined.

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.