CCL14 Predicts Oliguria and Dialysis Requirement in Patients with Moderate to Severe Acute Kidney Injury.

INTRODUCTION: AKI is a frequent complication of critical illness and portends poor outcome. CCL14 is a validated predictor of persistent severe AKI in critically ill patients. We examined the association of CCL14 with urine output within 48 h. METHODS: In pooled data from 2 studies of critically ill patients with KDIGO stage 2-3 AKI, CCL14 was measured by NEPHROCLEAR™ CCL14 Test on the Astute 140® Meter (low, intermediate, and high categories [1.3 and 13 ng/mL]). Average hourly urine output over 48 h, stage 3 AKI per urine output criterion on day 2, and composite of dialysis or death within 7 days were examined using multivariable mixed and logistic regression models. RESULTS: Of the 497 subjects with median age of 65 (56-74) years, 49% (242/497) were on diuretics. CCL14 concentration was low in 219 (44%), intermediate in 217 (44%), and high in 61 (12%) patients. In mixed regression analysis, hourly urine output over time was different within each CCL14 risk category based on diuretic use due to significant three-way interaction (p < 0.001). In logistic regression analysis, CCL14 risk category was independently associated with low urine output on day 2 per KDIGO stage 3 (adjusted for diuretic use and baseline clinical variables), and composite of dialysis or death within 7 days (adjusted for urine output within 48 h of CCL14 measurement). CONCLUSIONS: CCL14 measured in patients with moderate to severe AKI is associated with urine output trajectory within 48 h, oliguria on day 2, and dialysis within 7 days.

Sex bias in prediction and diagnosis of cardiac surgery associated acute kidney injury.

BACKGROUND: Female sex has been recognized as a risk factor for cardiac surgery associated acute kidney injury (CS-AKI). The current study sought to evaluate whether female sex is a risk factor for CS-AKI, or modifies the association of peri-operative change in serum creatinine with CS-AKI. METHODS: Observational study of adult patients undergoing cardiac surgery between 2000 and 2019 in a single U.S. center. The main variable of interest was registered patient sex, identified from electronic medical records. The main outcome was CS-AKI within 2 weeks of surgery. RESULTS: Of 58526 patients, 19353 (33%) were female; 12934 (22%) incurred AKI based on ≥ 0.3 mg/dL or ≥ 50% rise in serum creatinine (any AKI), 3320 (5.7%) had moderate to severe AKI, and 1018 (1.7%) required dialysis within 2 weeks of surgery. Female sex was associated with higher risk for AKI in models that were based on preoperative serum creatinine (OR, 1.35; 95% CI, 1.29-1.42), and lower risk with the use of estimated glomerular filtration, (OR, 0.90; 95% CI, 0.86-0.95). The risk for moderate to severe CS-AKI for a given immediate peri-operative change in serum creatinine was higher in female compared to male patients (p < .0001 and p < .0001 for non-linearity), and the association was modified by pre-operative kidney function (p < .0001 for interaction). CONCLUSIONS: The association of patient sex with CS-AKI and its direction was dependent on the operational definition of pre-operative kidney function, and differential outcome misclassification due to AKI defined by absolute change in serum creatinine.

Rapid implementation of an emergency on-site CKRT dialysate production system during the COVID-19 pandemic.

BACKGROUND: On December 29, 2021, during the delta wave of the Coronavirus Disease 2019 (COVID-19) pandemic, the stock of premanufactured solutions used for continuous kidney replacement therapy (CKRT) at the University of New Mexico Hospital (UNMH) was nearly exhausted with no resupply anticipated due to supply chain disruptions. Within hours, a backup plan, devised and tested 18 months prior, to locally produce CKRT dialysate was implemented. This report describes the emergency implementation and outcomes of this on-site CKRT dialysate production system. METHODS: This is a single-center retrospective case series and narrative report describing and reporting the outcomes of the implementation of an on-site CKRT dialysate production system. All adults treated with locally produced CKRT dialysate in December 2021 and January 2022 at UNMH were included. CKRT dialysate was produced locally using intermittent hemodialysis machines, hemodialysis concentrate, sterile parenteral nutrition bags, and connectors made of 3-D printed biocompatible rigid material. Outcomes analyzed included dialysate testing for composition and microbiologic contamination, CKRT prescription components, patient mortality, sequential organ failure assessment (SOFA) scores, and catheter-associated bloodstream infections (CLABSIs). RESULTS: Over 13 days, 22 patients were treated with 3,645 L of locally produced dialysate with a mean dose of 20.0 mL/kg/h. Fluid sample testing at 48 h revealed appropriate electrolyte composition and endotoxin levels and bacterial colony counts at or below the lower limit of detection. No CLABSIs occurred within 7 days of exposure to locally produced dialysate. In-hospital mortality was 81.8% and 28-day mortality was 68.2%, though illness severity was high, with a mean SOFA score of 14.5. CONCLUSIONS: Though producing CKRT fluid with IHD machines is not novel, this report represents the first description of the rapid and successful implementation of a backup plan for local CKRT dialysate production at a large academic medical center in the U.S. during the COVID-19 pandemic. Though conclusions are limited by the retrospective design and limited sample size of our analysis, our experience could serve as a guide for other centers navigating similar severe supply constraints in the future.

Predictive Accuracy of a Perioperative Laboratory Test-Based Prediction Model for Moderate to Severe Acute Kidney Injury After Cardiac Surgery.

Importance: Effective treatment of acute kidney injury (AKI) is predicated on timely diagnosis; however, the lag in the increase in serum creatinine levels after kidney injury may delay therapy initiation. Objective: To determine the derivation and validation of predictive models for AKI after cardiac surgery. Design, Setting, and Participants: Multivariable prediction models were derived based on a retrospective observational cohort of adult patients undergoing cardiac surgery between January 2000 and December 2019 from a US academic medical center (n = 58 526) and subsequently validated on an external cohort from 3 US community hospitals (n = 4734). The date of final follow-up was January 15, 2020. Exposures: Perioperative change in serum creatinine and postoperative blood urea nitrogen, serum sodium, potassium, bicarbonate, and albumin from the first metabolic panel after cardiac surgery. Main Outcomes and Measures: Area under the receiver-operating characteristic curve (AUC) and calibration measures for moderate to severe AKI, per Kidney Disease: Improving Global Outcomes (KDIGO), and AKI requiring dialysis prediction models within 72 hours and 14 days following surgery. Results: In a derivation cohort of 58 526 patients (median [IQR] age, 66 [56-74] years; 39 173 [67%] men; 51 503 [91%] White participants), the rates of moderate to severe AKI and AKIrequiring dialysis were 2674 (4.6%) and 868 (1.48%) within 72 hours and 3156 (5.4%) and 1018 (1.74%) within 14 days after surgery. The median (IQR) interval to first metabolic panel from conclusion of the surgical procedure was 10 (7-12) hours. In the derivation cohort, the metabolic panel-based models had excellent predictive discrimination for moderate to severe AKI within 72 hours (AUC, 0.876 [95% CI, 0.869-0.883]) and 14 days (AUC, 0.854 [95% CI, 0.850-0.861]) after the surgical procedure and for AKI requiring dialysis within 72 hours (AUC, 0.916 [95% CI, 0.907-0.926]) and 14 days (AUC, 0.900 [95% CI, 0.889-0.909]) after the surgical procedure. In the validation cohort of 4734 patients (median [IQR] age, 67 (60-74) years; 3361 [71%] men; 3977 [87%] White participants), the models for moderate to severe AKI after the surgical procedure showed AUCs of 0.860 (95% CI, 0.838-0.882) within 72 hours and 0.842 (95% CI, 0.820-0.865) within 14 days and the models for AKI requiring dialysis and 14 days had an AUC of 0.879 (95% CI, 0.840-0.918) within 72 hours and 0.873 (95% CI, 0.836-0.910) within 14 days after the surgical procedure. Calibration assessed by Spiegelhalter z test showed P >.05 indicating adequate calibration for both validation and derivation models. Conclusions and Relevance: Among patients undergoing cardiac surgery, a prediction model based on perioperative basic metabolic panel laboratory values demonstrated good predictive accuracy for moderate to severe acute kidney injury within 72 hours and 14 days after the surgical procedure. Further research is needed to determine whether use of the risk prediction tool improves clinical outcomes.

Partial Nephrectomy for Patients with Severe Chronic Kidney Disease-Is It Worthwhile?

PURPOSE: Partial nephrectomy is prioritized over radical nephrectomy in patients with chronic kidney disease whenever feasible. However, we hypothesized that some patients with severe chronic kidney disease might rapidly progress to end stage renal disease, in which case the morbidity that can be associated with partial nephrectomy would not be justified. MATERIALS AND METHODS: A retrospective review of all 62 patients with stage IV chronic kidney disease undergoing partial nephrectomy at our institution (1999-2015) was performed. We analyzed preoperative/intraoperative factors and postoperative outcomes. Survival-analyses evaluated factors associated with time-to-progression to end stage renal disease the primary end point. RESULTS: Median age was 67 years, 71% of patients were male, and 84% Caucasian. Comorbidities included hypertension (94%), cardiovascular disease (53%) and diabetes (32%). Median preoperative estimated glomerular filtration rate was 23 ml/minute/1.73 m2 and 73% had an open approach. Benign pathology was found in 10 (16%) patients; only 23 (37%) and 7 (11%) patients had tumor grade 3/4 or pT3a disease, respectively. Unfavorable outcomes occurred in 15 patients (24%) defined as either 90-day mortality (3%), postoperative complication Clavien IIIb or greater (14%), or positive surgical margin (12%). Median time to progression to end stage renal disease was only 27 months (58 months for preoperative glomerular filtration rate greater than 25 ml/minute/1.73 m2 versus only 14 months when preoperative glomerular filtration rate was less than 20 ml/minute/1.73 m2). On multivariable analysis African American race (HR 2.55 [1.10-5.95]), preoperative estimated glomerular filtration rate 20 to 25 ml/minute/1.73 m2 or less than 20 ml/minute/1.73 m2 (HR 2.59 [1.16-5.84] and 5.03 [2.03-12.4], respectively) and minimally invasive approach (HR 2.05 [1.01-4.19]) were independently associated with progression to end stage renal disease. CONCLUSIONS: Our data suggest that some patients with stage IV chronic kidney disease undergoing partial nephrectomy have substantial comorbidities and nonaggressive pathology, and are at risk for unfavorable perioperative outcomes and rapid-progression to end stage renal disease. Renal mass biopsy should be strongly considered to improve patient-selection. Alternate strategies (active surveillance or radical nephrectomy) may be more appropriate, particularly when partial nephrectomy is high complexity or when the patient is African American, or preoperative glomerular filtration rate is less than 25 ml/minute/1.73 m2.

Renal Cancer Surgery in Patients without Preexisting Chronic Kidney Disease-Is There a Survival Benefit for Partial Nephrectomy?

PURPOSE: Retrospective studies suggest that partial nephrectomy provides improved survival compared to radical nephrectomy even when performed electively. However, selection bias may contribute. We evaluated factors associated with nonrenal cancer related mortality after partial and radical nephrectomy in patients with a preoperative glomerular filtration rate of 60 ml/minute/1.73 m2 or greater. MATERIALS AND METHODS: We retrospectively evaluated the records of 3,133 patients with a preoperative glomerular filtration rate of 60 ml/minute/1.73 m2 or greater who underwent partial or radical nephrectomy. Nonrenal cancer related mortality was analyzed by the Kaplan-Meier test based on procedure and functional parameters, including the new baseline glomerular filtration rate. We used the Cox proportional hazards model to assess factors associated with nonrenal cancer related mortality among patients with a new baseline rate of 45 ml/minute/1.73 m2 or greater. RESULTS: Overall median age was 59 years and the median preoperative glomerular filtration rate was 85 ml/minute/1.73 m2. The new baseline glomerular filtration rate was 80 and 63 ml/minute/1.73 m2 and 10-year nonrenal cancer related mortality was 11.3% and 17.7% after partial and radical nephrectomy, respectively (each p <0.001). Median followup was 9.3 years. Nonrenal cancer related mortality was similar in all patients with a new baseline glomerular filtration rate of 45 ml/minute/1.73 m2 or greater (p = 0.26). However, it increased 50% or more in the 290 patients with a new baseline below this level (p = 0.001). In patients with a new baseline greater than 45 ml/minute/1.73 m2 10-year nonrenal cancer related mortality was still substantially improved after partial nephrectomy (10.6% vs 16.3%, p <0.001). In this population age, gender and partial vs radical nephrectomy were associated with nonrenal cancer related mortality on multivariable analysis (all p ≤0.001). In contrast, the increased new baseline glomerular filtration rate, as seen for partial nephrectomy, was not associated with reduced nonrenal cancer related mortality. CONCLUSIONS: In patients with a glomerular filtration rate of 60 ml/minute/1.73 m2 or greater who undergo partial or radical nephrectomy our data suggest that treatment should achieve a new baseline of 45 ml/minute/1.73 m2 or greater if feasible. Partial nephrectomy should be prioritized if needed to accomplish this. In patients with a new baseline rate of 45 ml/minute/1.73 m2 or greater partial nephrectomy was associated with improved survival. However, the functional dividend, namely the increased new baseline rate, failed to correlate, suggesting that selection bias may also impact outcomes.

Correction to: Clinical predictors of renal non-recovery in acute respiratory distress syndrome.

Following publication of the original article.

Clinical predictors of renal non-recovery in acute respiratory distress syndrome.

BACKGROUND: Acute kidney injury (AKI) is the most common extra-pulmonary organ failure in acute respiratory distress syndrome (ARDS). Renal recovery after AKI is determined by several factors. The objective of this study was to determine the predictors of renal non-recovery in ARDS patients. METHODS: A single center retrospective cohort study of patients with AKI after onset of ARDS. Patients with preexisting chronic kidney disease or intensive care unit stay < 24 h were excluded. AKI staging was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) 2012 guidelines. Renal non-recovery was defined as death, dialysis dependence, serum creatinine ≥1.5 times the baseline, or urine output < 0.5 mL/kg/h more than 6 h. RESULTS: Of the 244 patients that met study criteria, 60 (24.6%) had stage I AKI, 66 (27%) had stage II AKI, and 118 (48.4%) had stage III AKI. Of those, 148 (60.7%) patients had renal non-recovery. On multivariable analysis, factors associated with renal non-recovery were a higher stage of AKI (odds ratio [OR] stage II 5.71, 95% confidence interval [CI] 2.17-14.98; OR stage III 45.85, 95% CI 16.27-129.2), delay in the onset of AKI (OR 1.12, 95% CI 1.03-1.21), history of malignancy (OR 4.02, 95% CI 1.59-10.15), septic shock (OR 3.2, 95% CI 1.52-6.76), and a higher tidal volume on day 1-3 of ARDS (OR 1.41, 95% CI 1.05-1.90). Subgroup analysis of survival at day 28 of ARDS also found that higher severity of AKI (OR stage II 8.17, 95% CI 0.84-79.91; OR stage III 111.67, 95% CI 12.69-982.91), delayed onset of AKI (OR 1.12, 95% CI 1.02-1.23), and active malignancy (OR 6.55, 95% CI 1.34-32.04) were significant predictors of renal non-recovery. CONCLUSIONS: A higher stage of AKI, delayed onset of AKI, a history of malignancy, septic shock, and a higher tidal volume on day 1-3 of ARDS predicted renal non-recovery in ARDS patients. Among survivors, a higher stage of AKI, delayed onset of AKI, and a history of malignancy were associated with renal non-recovery.

Predictors of Long-Term Survival after Renal Cancer Surgery.

PURPOSE: Renal cancer surgery can adversely impact long-term function and survival. We evaluated predictors of chronic kidney disease 5 years and nonrenal cancer mortality 10 years after renal cancer surgery. MATERIALS AND METHODS: We analyzed the records of 4,283 patients who underwent renal cancer surgery from 1997 to 2008. Radical and partial nephrectomy were performed in 46% and 54% of patients, respectively. Cumulative probability ordinal modeling was used to predict chronic kidney disease status 5 years after surgery and multivariable logistic regression was used to predict nonrenal cancer mortality at 10 years. Relevant patient, tumor and functional covariates were incorporated, including the preoperative glomerular filtration rate (A), the new baseline glomerular filtration rate after surgery (B) and the glomerular filtration rate loss related to surgery (C), that is C = A - B. In contrast, partial or radical nephrectomy was not used in the models due to concerns about strong selection bias associated with the choice of procedure. RESULTS: Multivariable modeling established the preoperative glomerular filtration rate and the glomerular filtration rate loss related to surgery as the most important predictors of the development of chronic kidney disease (Spearman ρ = 0.78). Age, gender and race had secondary roles. Significant predictors of 10-year nonrenal cancer mortality were the preoperative glomerular filtration rate, the new baseline glomerular filtration rate, age, diabetes and heart disease (all p <0.05). Multivariable modeling established age and the preoperative glomerular filtration rate as the most important predictors of 10-year nonrenal cancer mortality (c-index 0.71) while the glomerular filtration rate loss related to surgery only changed absolute mortality estimates 1% to 3%. CONCLUSIONS: Glomerular filtration rate loss related to renal cancer surgery, whether due to partial or radical nephrectomy, influences the risk of chronic kidney disease but it may have less impact on survival. In contrast, age and the preoperative glomerular filtration rate, which reflects general health status, are more robust predictors of nonrenal cancer mortality, at least in patients with good preoperative function or mild chronic kidney disease.

Analysis of survival for patients with chronic kidney disease primarily related to renal cancer surgery.

OBJECTIVES: To evaluate predictors of long-term survival for patients with chronic kidney disease primarily due to surgery (CKD-S). Patients with CKD-S have generally good survival that approximates patients who do not have CKD even after renal cancer surgery (RCS), yet there may be heterogeneity within this cohort. PATIENTS AND METHODS: From 1997 to 2008, 4 246 patients underwent RCS at our centre. The median (interquartile range [IQR]) follow-up was 9.4 (7.3-11.0) years. New baseline glomerular filtration rate (GFR) was defined as highest GFR between nadir and 6 weeks after RCS. We retrospectively evaluated three cohorts: no-CKD (new baseline GFR of ≥60 mL/min/1.73 m2 ); CKD-S (new baseline GFR of <60 mL/min/1.73 m2 but preoperative GFR of ≥60 mL/min/1.73 m2 ); and CKD due to medical aetiologies who then require RCS (CKD-M/S, preoperative and new baseline GFR both <60 mL/min/1.73 m2 ). Analysis focused primarily on non-renal cancer-related survival (NRCRS) for the CKD-S cohort. Kaplan-Meier analysis assessed the longitudinal impact of new baseline GFR (45-60 mL/min/1.73 m2 vs <45 mL/min/1.73 m2 ) and Cox regression evaluated relative impact of preoperative GFR, new baseline GFR, and relevant demographics/comorbidities. RESULTS: Of the 4 246 patients who underwent RCS, 931 had CKD-S and 1 113 had CKD-M/S, whilst 2 202 had no-CKD even after RCS. Partial/radical nephrectomy (PN/RN) was performed in 54%/46% of the patients, respectively. For CKD-S, 641 patients had a new baseline GFR of 45-60 mL/min/1.73 m2 and 290 had a new baseline GFR of <45 mL/min/1.73 m2 . Kaplan-Meier analysis showed significantly reduced NRCRS for patients with CKD-S with a GFR of <45 mL/min/1.73 m2 compared to those with no-CKD or CKD-S with a GFR of 45-60 mL/min/1.73 m2 (both P ≤ 0.004), and competing risk analysis confirmed this (P < 0.001). Age, gender, heart disease, and new baseline GFR were all associated independently with NRCRS for patients with CKD-S (all P ≤ 0.02). CONCLUSION: Our data suggest that CKD-S is heterogeneous, and patients with a reduced new baseline GFR have compromised survival, particularly if <45 mL/min/1.73 m2 . Our findings may have implications regarding choice of PN/RN in patients at risk of developing CKD-S.

Cytokine Clearances in Critically Ill Patients on Continuous Renal Replacement Therapy.

BACKGROUND/AIMS: We sought to quantify any differences in cytokine clearance between continuous venovenous hemofiltration (CVVH-convective) compared to continuous venovenous hemodialysis (CVVHD-diffusive). METHODS: We conducted a 20 patient, multicenter, prospective, open-label randomized trial (CVVH or CVVHD) at continuous renal -replacement therapy (CRRT) initiation. Blood, urine, and effluent were collected at 0, 4, 24, and 48 h after initiation of CRRT. Serum electrolytes, cytokines levels, and clearances were measured. Cytokines studies included IL-1ß, IL-1RA, IL-6, IL-10, and TNFα. RESULTS: We randomized 20 patients to receive CRRT. After 4 h of CRRT there was no difference in total cytokine levels or change in cytokine concentrations across the 2 groups. With the exception of IL-1 RA, all cytokines levels decreased across patient groups regardless of modality. There was no significant difference in cytokine concentration across CRRT modality for any time point. CONCLUSION: Within the first 4 h of CRRT initiation, there is no significant difference between cytokine or solute clearance between CVVH and CVVHD.

Proteinuria is a Predictor of Renal Functional Decline in Patients with Kidney Cancer.

PURPOSE: Prior studies have shown that 26% to 34% of patients with suspected renal cancers have a glomerular filtration rate less than 60 ml/minute/1.73 m(2) but limited information exists regarding proteinuria. We investigated the extent of proteinuria in patients with renal tumors to determine the impact on the classification and progression of chronic kidney disease. MATERIALS AND METHODS: Among 1,622 patients evaluated between 1999 and 2014, 1,016 had preoperative creatinine and proteinuria measurements available. Patients were classified according to the risk of chronic kidney disease progression into low, moderately increased, high and very high risk groups according to 2012 KDIGO guidelines. Predictors of risk group and chronic kidney disease progression were analyzed using univariable and multivariate models. RESULTS: Before treatment 32% had a glomerular filtration rate less than 60 ml/minute/1.73 m(2). Preoperative proteinuria was present in 22%. Proteinuria was detected in 30% with a reduced glomerular filtration rate and 18% with a normal glomerular filtration rate. Among the 44% at increased risk for chronic kidney disease progression 24%, 12% and 8% were at moderately increased, high and very high risk, respectively. The presence of proteinuria also reclassified 25% with stage III chronic kidney disease as high or very high risk. KDIGO classification predicted renal functional decline, which occurred in 2.2%, 4.4%, 9.4% and 34.6% at 3 years in low, moderately increased, high and very high risk categories, respectively. Predictors of KDIGO group included age and tumor size (each p <0.001), and the main predictors of renal functional decline were KDIGO group, tumor size and radical nephrectomy (each p <0.0001). CONCLUSIONS: Identification of chronic kidney disease using only glomerular filtration rate left 18% of patients undiagnosed. The assessment of glomerular filtration rate and proteinuria classified patients according to risk of chronic kidney disease progression, identifying 44% to be at increased risk. As proteinuria predicted renal functional decline, we advocate for routine evaluation before treatment.

Decline in renal function after partial nephrectomy: etiology and prevention.

PURPOSE: Partial nephrectomy is the reference standard for the management of small renal tumors and is commonly used for localized kidney cancer. A primary goal of partial nephrectomy is to preserve as much renal function as possible. New baseline glomerular filtration rate after partial nephrectomy can have prognostic significance with respect to long-term outcomes. Recent studies provide an increased understanding of the factors that determine functional outcomes after partial nephrectomy as well as preventive measures to minimize functional decline. We review these advances, highlight ongoing controversies and stimulate further research. MATERIALS AND METHODS: A comprehensive literature review consistent with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria was performed from January 2006 to April 2014 using PubMed®, Cochrane and Ovid Medline. Key words included partial nephrectomy, renal function, warm ischemia, hypothermia, nephron mass, parenchymal volume, surgical approaches to partial nephrectomy, preoperative and intraoperative imaging, enucleation, hemostatic agents and energy based resection. Relevant reviews were also examined as well as their cited references. An additional Google Scholar search was conducted to broaden the scope of the review. Only English language articles were included in the analysis. The primary outcomes of interest were the new baseline level of function after early postoperative recovery, percent decline in function, potential etiologies and preventive measures. RESULTS: Decline in function after partial nephrectomy averages approximately 20% in the operated kidney, and can be due to incomplete recovery from the ischemic insult or loss of nephron mass related to parenchymal excision or collateral damage during reconstruction. Compensatory hypertrophy in the contralateral kidney after partial nephrectomy in adults is marginal and decline in global renal function for patients with 2 kidneys averages about 10%, although there is some variance based on tumor size and location. Irreversible ischemic injury can be minimized by pharmacological intervention or surgical approaches such as hypothermia, limited warm ischemia, or zero or segmental ischemia. Excessive loss of nephron mass can be minimized by improved preoperative or intraoperative imaging, use of a bloodless field, enucleation and vascular microdissection. Hemostatic agents or energy based resection that minimizes the need for parenchymal and capsular suturing can also optimize preservation of the vascularized nephron mass. CONCLUSIONS: Our understanding of the decline in renal function after partial nephrectomy has advanced considerably, including better appreciation of its magnitude and impact in various settings, possible etiologies and potential preventive measures. Many controversies persist and this remains an important area of investigation.

Renal failure requiring dialysis complicating slow continuous ultrafiltration in acute heart failure: importance of systolic perfusion pressure.

BACKGROUND: Recent reports have raised concerns regarding renal outcomes in patients with decompensated acute heart failure (HF) treated with slow continuous ultrafiltration (SCUF). The purpose of this study was to identify risk factors for renal failure (RF) requiring dialysis in patients with acute HF initiated on SCUF. METHODS AND RESULTS: We studied 63 consecutive patients with acute HF who required SCUF because of congestion refractory to hemodynamically guided intensive medical therapy. Median serum creatinine at SCUF initiation was higher in patients who developed RF requiring dialysis [2.5 (interquartile range 1.8-3.3) vs 1.6 (1.2-2.3) mg/dL; P < .001]. Weight loss within 48 hours of SCUF initiation was larger in patients who did not progress to RF [-6 (-10 to -2) vs -4 (-6 to -2) kg; P = .03]. Systolic perfusion pressure had a nonlinear association with RF requiring dialysis, with a threshold effect noted at 90 mm Hg. Twelve-month mortality in patients who were moved to dialysis versus those who were not was 95% versus 35%, respectively (P < .001). CONCLUSIONS: In patients with acute HF initiated on SCUF, onset of RF requiring dialysis is associated with high mortality. Systolic perfusion pressure which incorporates both perfusion and venous congestion parameters may present a modifiable risk factor for worsening RF during SCUF in acute HF patients.

Chronic kidney disease due to surgical removal of nephrons: relative rates of progression and survival.

PURPOSE: Chronic kidney disease is associated with a higher likelihood of progression to end stage renal disease and increased mortality rates. However, the etiology of nephron loss may modify the rate of chronic kidney disease progression and overall survival. MATERIALS AND METHODS: Patients with suspected renal malignancy who had a new baseline glomerular filtration rate of less than 60 ml/minute/1.73 m(2) 6 weeks after surgery were divided into the 2 groups of surgically induced chronic kidney disease (preoperative glomerular filtration rate greater than 60 ml/minute/1.73 m(2)) and preexisting chronic kidney disease due to medical causes followed by surgery. An independent cohort of subjects with chronic kidney disease entirely due to medical causes served as a comparator. RESULTS: Renal cancer surgery yielded cohorts with surgically induced chronic kidney disease (1,097) and chronic kidney disease due to medical causes followed by surgery (1,053), whereas the group with chronic kidney disease due to medical causes consisted of 42,658 subjects. The patients with chronic kidney disease due to medical causes and chronic kidney disease from medical causes followed by surgery were older compared to those with surgically induced chronic kidney disease, had more medical comorbidities and had a lower baseline glomerular filtration rate (all p <0.001). The group with chronic kidney disease due to medical causes followed by surgery had a lower mean (±SD) new baseline glomerular filtration rate (37±10) compared to the surgically induced chronic kidney disease (48±9) and chronic kidney disease due to medical comorbidities (47±10) groups (p <0.001). The probability of progressive decline in renal function (50% decrease in glomerular filtration rate or need for dialysis) at 3 years was lowest for surgically induced chronic kidney disease, intermediate for chronic kidney disease from medical causes followed by surgery and highest for chronic kidney disease from medical causes when age, gender, race, comorbidities and new baseline glomerular filtration rate were considered (p <0.001). Nonrenal cancer related mortality was substantially lower for those with surgically induced chronic kidney disease compared to the other groups (p <0.001). CONCLUSIONS: Our data suggest that surgically induced chronic kidney disease has a lower rate of functional decline and less impact on survival than chronic kidney disease due to medical causes. These data have potential implications with respect to chronic kidney disease classification and patient counseling for surgical management of various renal disorders including renal cancer.

Poorly functioning kidneys recover from ischemia after partial nephrectomy as well as strongly functioning kidneys.

PURPOSE: Poorly functioning kidneys may not recover from ischemia as well as strongly functioning kidneys. This could impact surgical approaches to partial nephrectomy. MATERIALS AND METHODS: We analyzed the records of 155 consecutive patients treated with partial nephrectomy who underwent appropriate studies to facilitate analysis of function and parenchymal mass in the operated kidney, including computerized tomography and glomerular filtration rate measurement within 2 months preoperatively and 4 to 12 months postoperatively. Patients with a contralateral kidney also underwent renal scan in the same time frame to provide split renal function. Computerized tomography was done to measure functional parenchymal volume before and after partial nephrectomy. Recovery from ischemia, defined as percent glomerular filtration rate saved/percent volume saved, was considered 100% if all nephrons recovered from the ischemic insult. RESULTS: The median R.E.N.A.L. nephrotomy score was 8. Cold ischemia was used in 64 patients and limited warm ischemia was used in 91 (median 27 and 20 minutes, respectively). The median percent glomerular filtration rate saved in the operated kidney was 80% and the median parenchymal volume saved was 83%. The overall median rate of recovery from ischemia was 95%, including 100% for cold ischemia and 92% for limited warm ischemia. Recovery from ischemia was approximately 100% and was similar for all strata of preoperative estimated glomerular filtration rates in the operated kidney (p = 0.24), even in the warm ischemia subgroup. CONCLUSIONS: Our results suggest that the quantity of parenchyma preserved is the main determinant of the postoperative glomerular filtration rate after partial nephrectomy as long as limited warm ischemia or hypothermia is used. Even poorly functioning kidneys recover well from the ischemic insult proportionate to the amount of parenchyma preserved.

Predictors of precision of excision and reconstruction in partial nephrectomy.

PURPOSE: The precision of excision and reconstruction to optimize vascularized parenchymal preservation is a major determinant of renal function after partial nephrectomy. We assessed partial nephrectomy surgical precision using volumetric computerized tomography and analyzed predictive factors. MATERIALS AND METHODS: We analyzed the records of 122 patients treated with partial nephrectomy in whom detailed analysis of the precision of excision and reconstruction specific to the operated kidney could be performed. We used volumetric computerized tomography to measure functional parenchymal volume before and after partial nephrectomy in the operated kidney. The glomerular filtration rate in the operated kidney was determined by the MDRD2 (Modification of Diet in Renal Disease 2) equation along with renal scan in patients with a contralateral kidney. Surgical precision was defined as actual postoperative parenchymal volume/predicted postoperative parenchymal volume, presuming loss of a 5 mm rim of normal parenchyma related to excision and reconstruction. RESULTS: Median patient age was 61 years and 64 patients (52%) underwent an open procedure. Cold ischemia was used in 50 patients (median 26 minutes) and limited warm ischemia (median 20 minutes) was used in 72. The R.E.N.A.L. (radius, exophytic/endophytic, nearness of tumor to collecting system or sinus, anterior/posterior and location relative to polar line) nephrometry score indicated low, intermediate and high complexity in 43 (35%), 55 (45%) and 24 patients (20%), respectively. A total of 45 patients (37%) with a solitary kidney were included in analysis. The median precision of excision and reconstruction was 93%. The median preserved glomerular filtration rate was 80% in the operated kidney. A solitary kidney was the only significant predictor of excision and reconstruction precision on univariable and multivariable analysis. CONCLUSIONS: A solitary kidney significantly impacted partial nephrectomy surgical precision. This was likely related to the recognized need to preserve as much renal parenchyma as possible to optimize renal function in the absence of a contralateral kidney.

Compensatory hypertrophy after partial and radical nephrectomy in adults.

PURPOSE: We assessed compensatory hypertrophy in the contralateral kidney after partial and radical nephrectomy in adults. We also examined predictive factors to facilitate more accurate estimation of global renal function after surgery. MATERIALS AND METHODS: We analyzed the records of 172 patients who underwent partial or radical nephrectomy with appropriate studies to determine function and parenchymal mass specifically in the operated and contralateral kidneys. All patients required renal scans to provide split renal function preoperatively and postoperatively. Parenchymal volume was measured by computerized tomography. All studies were done less than 2 months preoperatively and 4 to 12 months postoperatively. RESULTS: A total of 113 and 59 patients underwent partial and radical nephrectomy, and median tumor size was 3.5 and 7.0 cm, respectively (p <0.0001). Of patients treated with partial nephrectomy 19% had high complexity tumor compared to 80% of those treated with radical nephrectomy (p <0.0001). Median ipsilateral parenchymal volume was reduced 18% after partial nephrectomy and the median glomerular filtration rate in this kidney decreased 24.4%. The median contralateral kidney function increase after partial nephrectomy was 2.3% vs 21.1% after radical nephrectomy (p <0.0001). Median global function decreased 9.6% after partial nephrectomy vs 32.2% after radical nephrectomy (p <0.0001). A larger percent parenchymal volume loss (p = 0.0001) and fewer comorbidities (p = 0.0072) significantly correlated with greater compensatory hypertrophy in the contralateral kidney on multivariable analysis. CONCLUSIONS: Compensatory hypertrophy in adults was limited after partial nephrectomy and it correlated significantly with the amount of parenchymal volume excised. Healthier patients also appeared to respond better. These results may allow for more accurate estimation of global renal function after partial and radical nephrectomy.

Is all chronic kidney disease created equal?

PURPOSE OF REVIEW: Chronic kidney disease (CKD) has generally been characterized functionally as a glomerular filtration rate (GFR) less than 60 ml/min/1.73 m², without accounting for cause, signs of structural damage, or relative risk of sequelae. Recently released guidelines define CKD as abnormalities of kidney structure or function, present for more than 3 months. We review the recent literature about CKD and its implications for renal surgery. RECENT FINDINGS: Most estimates of GFR are based on serum creatinine, after adjusting for age, race, sex, and/or body mass. Recent research indicates that many individuals have GFR values less than 60 ml/min/1.73 m² without other manifestations of CKD. Nephron loss due to normal aging or renal surgery (CKD-S) may have lower likelihood of CKD progression, and may infer better survival, compared to individuals with the same degree of CKD due to medical causes. Patients with mild and moderate CKD due to surgical nephron loss may benefit from an alternative measurement method of renal function such as cystatin-C-derived or directly measured GFR. SUMMARY: CKD includes a diverse group of individuals with reduced GFR from a variety of causes. Classification of CKD according to GFR, albuminuria, and cause, may improve the management of patients with reduced GFR, as some causes (e.g., nephrectomy and aging) appear to be associated with a relatively low risk of progression.