Postoperative Increase In Serum Creatinine Research Articles

Early Creatinine Changes After Aortic Valve Replacement and Late Survival, Heart Failure, and Chronic Kidney Disease in a National Registry

BackgroundThe impact of small increases in serum creatinine after surgical aortic valve replacement (SAVR) that fail to meet the acute kidney injury stage 1 criteria is unknown. The aim of this study was to investigate prognosis after primary SAVR in patients with small increases in postoperative serum creatinine. MethodsThis observational cohort study included all adult patients who underwent primary SAVR in Sweden from 2009 to 2022. The primary outcome was all-cause mortality. Secondary outcomes were chronic kidney disease and heart failure. Regression standardization addressed confounding. ResultsIn 16,766 patients, 4074 (24.2%) had no change in postoperative serum creatinine, 5764 (34.3%) had a small increase in postoperative serum creatinine (0.06 mg/dL ≤ Δserum creatinine <0.3 mg/dL), and 2753 (16.4%) fulfilled the Kidney Disease Improving Global Outcomes acute kidney injury stage 1 criteria. The mean age was 67 years, and 31% of patients were female. No significant difference in long-term all-cause mortality was observed in the no change group at 13 years compared with the small increase group (absolute survival difference, 2.3% [95% CI, 0%-4.6%]). A stepwise increase in the risk of 30-day mortality was observed with increasing changes in serum creatinine. At 13 years of follow-up, there was a significant difference in the risk of chronic kidney disease (absolute difference, 2.8% [95% CI, 1.0%-4.5%]) and heart failure (absolute difference, 3.5% [95% CI, 1.3%-5.7%]) between the no change and small increase groups. ConclusionsA small increase in postoperative serum creatinine after SAVR was associated with an increased risk of adverse outcomes. The acute kidney injury definition may benefit from including more reliable and specific biomarkers together with small creatinine increases to detect kidney injury.

Perioperative Acute Renal Injury: Revisiting Pathophysiology.

Acute renal dysfunction and subsequent acute renal failure after cardiac surgery are associated with high mortality and morbidity. Early therapeutic or preventive intervention is hampered by the lack of an early biomarker for acute renal injury. Recent studies showed that urinary neutrophil gelatinase-associated lipocalin (NGAL or lipocalin 2) is upregulated early (within 1 to 3 h) after murine renal injury and in pediatric acute renal dysfunction after cardiac surgery. The authors hypothesized that postoperative urinary NGAL concentrations are increased in adult patients developing acute renal dysfunction after cardiac surgery compared with patients without acute renal dysfunction. After institutional review board approval, 81 cardiac surgical patients were prospectively studied. Urine samples were collected immediately before incision and at various time intervals after surgery for NGAL analysis by quantitative immunoblotting. Acute renal dysfunction was defined as peak postoperative serum creatinine increase by 50% or greater compared with preoperative serum creatinine. Sixteen of 81 patients (20%) developed postoperative acute renal dysfunction, and the mean urinary NGAL concentrations in patients who developed acute renal dysfunction were significantly higher early after surgery (after 1 h, mean ± SD, 4,195±6,520 vs. 1,068±2,129ng/ml; P < 0.01) compared with patients who did not develop acute renal dysfunction. Mean urinary NGAL concentrations continued to increase and remained significantly higher at 3 and 18 h after cardiac surgery in patients with acute renal dysfunction. In contrast, urinary NGAL in patients without acute renal dysfunction decreased rapidly after cardiac surgery. Patients developing postoperative acute renal dysfunction had significantly higher urinary NGAL concentrations early after cardiac surgery. Urinary NGAL may therefore be a useful early biomarker of acute renal dysfunction after cardiac surgery. These findings may facilitate the early detection of acute renal injury and potentially prevent progression to acute renal failure.

Comparison between the Effects of Loxoprofen and Acetaminophen on Postoperative Pain Following Radical Prostatectomy: A Propensity Score Matching Analysis

Non-steroidal anti-inflammatory medications are associated with renal impairment. However, there is little information on whether these medications affect postoperative renal function compared with acetaminophen. The objective of this study was to compare the effects of acetaminophen and loxoprofen, used as postoperative analgesic, effect on postoperative analgesia using propensity score matching analysis. We retrospectively enrolled 328 patients treated with loxoprofen or acetaminophen after open radical prostatectomy between October 2017 and February 2020. We analyzed postoperative pain intensity, the incidence rate of acute kidney injury, drug-induced liver injury, and rate of elevation in serum creatinine after open radical prostatectomy. Eighty-one matched pairs of patients treated with loxoprofen or acetaminophen were selected using propensity score matching analysis. The postoperative numerical rating scale was significantly higher in the acetaminophen group than in the loxoprofen group on postoperative day 5. The use of patient-controlled anesthesia and rescue analgesics was significantly higher in the acetaminophen group than in the loxoprofen group. The loxoprofen group had a significantly higher postoperative increase in serum creatinine than the acetaminophen group on postoperative days 5 and 8. The incidence of acute kidney injury was 4.9% in the loxoprofen group and 0% in the acetaminophen group, while the incidence of drug-induced liver injury was 0% in both groups. Acetaminophen appears to be safer than loxoprofen in terms of effects on renal function. Nevertheless, the number of acetaminophen doses and the dose per dose may need to be increased for patients with significant postoperative pain.

Acute kidney injury after liver surgery: does postoperative urine output correlate with postoperative serum creatinine?

BackgroundAcute kidney injury (AKI) after hepatectomy occurs in around 10% of cases. AKI is often defined based only on postoperative serum creatinine increase. This study aimed to assess if postoperative urine output (UO) correlated with serum creatinine after hepatectomy. MethodsAll consecutive hepatectomy patients (2010–2016) were assessed. AKI was defined according to KDIGO criteria: serum creatinine increase ≥26.5 μmol/l, creatinine increase ≥1.5x baseline creatinine, or postoperative oliguria. Oliguria was defined as daily mean UO <0.5 mL/kg/h. AKI was subdivided into creatinine-based or oliguria-based AKI according to the defining criterion. ResultsOut of 285 patients, AKI was observed in 79 cases (28%). Creatinine-based AKI occurred in 25 patients (9%) and oliguria-based only AKI in 54 patients (19%). Ten patients fulfilled both criteria (4%). Postoperative UO correlated poorly with postoperative serum creatinine level in both whole cohort (rho = −0.34, p <0.001) and AKI subgroup (rho = −0.189, p = 0.124). No association was found between postoperative oliguria and postoperative serum creatinine increase (HR = 0.5, 95%CI: 0.2–1.9, p = 0.341). On multivariable analysis, operation duration >360 minutes was the only predictor of creatinine increase (HR = 3.6, 95%CI: 1.1–11.4, p = 0.032). ConclusionPostoperative UO showed poor correlation with postoperative serum creatinine both in all patients and AKI patients. Surgery duration >360 minutes appeared as the only independent predictor of postoperative serum creatinine increase.

Safety of a Restrictive versus Liberal Approach to Red Blood Cell Transfusion on the Outcome of AKI in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

Safely reducing red blood cell transfusions can prevent transfusion-related adverse effects, conserve the blood supply, and reduce health care costs. Both anemia and red blood cell transfusion are independently associated with AKI, but observational data are insufficient to determine whether a restrictive approach to transfusion can be used without increasing AKI risk. In a prespecified kidney substudy of a randomized noninferiority trial, we compared a restrictive threshold for red blood cell transfusion (transfuse if hemoglobin<7.5 g/dl, intraoperatively and postoperatively) with a liberal threshold (transfuse if hemoglobin<9.5 g/dl in the operating room or intensive care unit, or if hemoglobin<8.5 g/dl on the nonintensive care ward). We studied 4531 patients undergoing cardiac surgery with cardiopulmonary bypass who had a moderate-to-high risk of perioperative death. The substudy's primary outcome was AKI, defined as a postoperative increase in serum creatinine of ≥0.3 mg/dl within 48 hours of surgery, or ≥50% within 7 days of surgery. Patients in the restrictive-threshold group received significantly fewer transfusions than patients in the liberal-threshold group (1.8 versus 2.9 on average, or 38% fewer transfusions in the restricted-threshold group compared with the liberal-threshold group; P<0.001). AKI occurred in 27.7% of patients in the restrictive-threshold group (624 of 2251) and in 27.9% of patients in the liberal-threshold group (636 of 2280). Similarly, among patients with preoperative CKD, AKI occurred in 33.6% of patients in the restrictive-threshold group (258 of 767) and in 32.5% of patients in the liberal-threshold group (252 of 775). Among patients undergoing cardiac surgery, a restrictive transfusion approach resulted in fewer red blood cell transfusions without increasing the risk of AKI.

Acute Kidney Injury Classification Underestimates Long-Term Mortality After Cardiac Valve Operations

Perioperative acute kidney injury (AKI) is an important predictor of long-term all-cause mortality after coronary artery bypass (CABG). However, the effect of AKI on long-term mortality after cardiac valve operations is hitherto undocumented. Perioperative renal injury and long-term all-cause mortality after valve operations were studied in a prospective cohort of patients undergoing solitary valve operations (n= 2,806) or valve operations combined with CABG (n= 1,260) with up to 18 years of follow-up. Postoperative serum creatinine increase was classified according to AKI staging 0 to 3. Patients undergoing solitary CABG (n= 4,938) with cardiopulmonary bypass served as reference. In both valve and valve+CABG operations, postoperative renal injury of AKI stage 1 or higher was progressively associated with an increase in long-term mortality (hazard ratio [HR], 2.27, p < 0.05 for valve; HR, 1.65, p < 0.05 for valve+CABG; HR, 1.56, p < 0.05 for CABG). Notably, the mortality risk increased already substantially at serum creatinine increases of 10% to 25%-that is, far below the threshold for AKI stage 1 after valve operations (HR, 1.39, p < 0.05), but not after valve operations combined with CABG or CABG only. An increase in serum creatinine by more than 10% during the first week after valve operation is associated with an increased risk for long-term mortality after cardiac valve operation. Thus, AKI classification clearly underestimates long-term mortality risk in patients undergoing valve operations.

Differences and similarities in risk factors for postoperative acute kidney injury between younger and older adults undergoing cardiac surgery

ObjectivesAcute kidney injury is a frequent complication after cardiac surgery. The purpose of this study was to assess the risk factors for acute kidney injury in patients ≤60 years of age undergoing cardiac surgery and to compare these risk factors with those identified in patients ≥65 years of age. MethodsFrom 2010 to 2012, 1253 patients ≤60 years (mean age 52 ± 9 years) and 2488 patients ≥65 years (mean age 74 ± 6 years) underwent cardiac surgery. Linear regression models using least absolute shrinkage and selection operator methods and mixed effects linear regression models were used to assess factors associated with maximum postoperative increase in serum creatinine in these two cohorts. ResultsIn both age groups, the following variables were associated independently with greater degrees of postoperative increase in serum creatinine on multivariable analysis: greater body mass index, peripheral vascular disease, preoperative use of diuretics, lower preoperative hemoglobin, preoperative intra-aortic balloon pump, urgent or emergent status, long cardiopulmonary bypass time, and hemofiltration. In younger patients, a greater increase in serum creatinine was associated with diabetes, and previous cardiac surgery, whereas female sex was associated with a lower degree of increase in serum creatinine. In older patients, a greater increase in serum creatinine was associated with age, hypertension, smoking, and lower left ventricular left ejection fraction. Operation type and coronary artery disease had a different impact on postoperative creatinine increase between younger and older patients. ConclusionsThis study identified both common and distinct risk factors associated with postoperative increase in serum creatinine between patients ≤60 years and those ≥65 years undergoing cardiac surgery. Importantly, all potentially modifiable risk factors were present in both groups.

Effect of perioperative sodium bicarbonate administration on renal function following cardiac surgery for infective endocarditis: a randomized, placebo-controlled trial

BackgroundPatients with infective endocarditis (IE) have an elevated risk of renal dysfunction because of extensive systemic inflammation and use of nephrotoxic antibiotics. In this randomized, placebo-controlled trial, we investigated whether perioperative sodium bicarbonate administration could attenuate postoperative renal dysfunction in patients with IE undergoing cardiac surgery.MethodsSeventy patients randomly received sodium chloride (n = 35) or sodium bicarbonate (n = 35). Sodium bicarbonate was administered as a 0.5 mmol/kg loading dose for 1 h commencing with anesthetic induction, followed by a 0.15 mmol/kg/h infusion for 23 h. The primary outcome was peak serum creatinine (SCr) level during the first 48 h postoperatively. The incidence of acute kidney injury, SCr level, estimated glomerular filtration rate, and major morbidity endpoints were assessed postoperatively.ResultsThe peak SCr during the first 48 h postoperatively (bicarbonate vs. control: 1.01 (0.74, 1.37) mg/dl vs. 0.88 (0.76, 1.27) mg/dl, P = 0.474) and the incidence of acute kidney injury (bicarbonate vs. control: 29% vs. 23%, P = 0.584) were similar in both groups. The postoperative increase in SCr above baseline was greater in the bicarbonate group than in the control group on postoperative day 2 (0.21 (0.07, 0.33) mg/dl vs. 0.06 (0.00, 0.23) mg/dl, P = 0.028) and postoperative day 5 (0.23 (0.08, 0.36) mg/dl vs. 0.06 (0.00, 0.23) mg/dl, P = 0.017).ConclusionsPerioperative sodium bicarbonate administration had no favorable impact on postoperative renal function and outcomes in patients with IE undergoing cardiac surgery. Instead, it was associated with possibly harmful renal effects, illustrated by a greater increase in SCr postoperatively, compared to control.Trial registrationClinicalTrials.gov, NCT01920126. Registered on 31 July 2013.

Increased risk of mortality after lower extremity bypass in individuals with acute kidney injury in the Vascular Quality Initiative

ObjectiveThe development of acute kidney injury (AKI) and its effect on prognosis after lower extremity bypass (LEB) surgery have not been well described. We determined risk factors associated with AKI in patients undergoing infrainguinal LEB surgery and whether individuals with AKI are at increased risk for cardiovascular events and mortality. MethodsData for 12,907 operations entered in the Vascular Quality Initiative (VQI) registry from January 2012 through April 2015 were retrospectively reviewed. Procedures performed on patients not on dialysis before the surgery with perioperative assessments of renal function were eligible for the study. AKI was defined as a postoperative increase in serum creatinine ≥0.5 mg/dL or new dialysis requirement. Logistic regression was performed to determine the effect of AKI on the risk of in-hospital cardiovascular events, including myocardial infarction, stroke, congestive heart failure, or arrhythmias, and mortality. Cox proportional hazards regression was performed to determine the risk of long-term mortality (median follow-up of 11.5 months). ResultsAKI developed after 507 (4%) of the 12,907 operations performed in 11,859 patients. After adjustment for demographic, clinical, and perioperative variables, AKI was associated with an increased risk of in-hospital cardiovascular events (odds ratio, 2.50; 95% confidence interval [CI], 1.91-3.28) and in-hospital mortality (odds ratio, 6.96; 95% CI, 3.94-12.31). Risk of mortality persisted over the course of follow-up (hazard ratio, 1.98; 95% CI, 1.58-2.47). ConclusionsAKI after LEB is associated with an increased risk of cardiovascular events and all-cause mortality. Further study should evaluate whether preoperative interventions before LEB can be effectively applied for at-risk patients to reduce the incidence of AKI and its associated morbidity and mortality.

Is there a risk of permanent renal dysfunction after primary total hip and knee joint replacements?

BackgroundPermanent renal dysfunction is considered as being a serious complication which may occur after major surgery and which furthermore may lead to increased morbidity and mortality. The objective of this study was to analyze the incidence of long-term postoperative renal dysfunction after primary total hip and knee joint replacements.MethodsLong-term postoperative renal dysfunction was analyzed in a retrospective study of 1301 consecutive primary total hip and knee joint replacements performed between January 2009 and December 2013. According to the RIFLE criteria, increased serum creatinine was an indicative of postoperative renal injury. The highest serum creatinine during the first postoperative week was chosen as a sign for maximum acute renal injury and was compared to the highest serum creatinine during the following 4–12 months.ResultsOne hundred and forty two patients with an increase in postoperative serum creatinine were included in the follow-up study. Six patients (4.2 %) died due to non-renal causes during the follow-up period. One patient died of severe renal injury, which was relatively very early postoperatively, and another patient had a rise in serum creatinine to 316 μmol/l during the follow-up period. All the remaining 132 patients (94 %) had full recovery with serum creatinine which returned to preoperative levels.ConclusionsThis study did not confirm that patients who underwent primary total hip and knee joint replacement surgery were at risk of developing permanent renal dysfunction up to 1 year after the index surgery.

Latent AKI is… still AKI: the quantification of the burden of renal dysfunction.

The association between pediatric cardiac surgery, acute kidney injury (AKI), and clinical outcomes has been studied several times in the recent literature. In this issue of Critical Care an interesting and original study analyzed the path from causal AKI entities to clinical AKI consequences through the application of structural equation modeling. The authors described the complex connections linking duration of cardiopulmonary bypass, cross clamp-time, and descriptors of low cardiac output syndrome to AKI modeled as a complex variable composed of post-operative serum creatinine increase of 50 % over baseline, urine output <0.5 ml/kg/h, and urine creatinine-normalized neutrophil gelatinase lipocalin within 12 h of surgery. Similarly, the causal relationships between AKI and hard outcomes in the analyzed population were verified and quantified. The authors, for the first time, produce a repeatable coefficient (0.741) that may become a useful quality benchmark and could be applied to test future interventions aiming to reduce the burden of AKI on children’s clinical course.

Fluid Retention is Alleviated by Crystalloid but Not by Colloid Fluid after Induction of General Anesthesia: An Open-Labeled Clinical Trial

Background: Renal fluid conservation, which is possible to quantify by urine analysis, is often caused by dehydration. The present study aimed to determine whether such fluid retention could be reversed by crystalloid and/or colloid fluid during surgery. Methods: Urine colour, specific weight, osmolality and creatinine concentration were used to calculate a “fluid retention index” (FRI) in 108 patients undergoing major abdominal surgery. Urine was collected at baseline and after flow-guided fluid volume optimisation with hydroxyethyl starch 130/0.4 (n=86) or Ringer's lactate (n=22). The third sample was taken after one hour of surgery. Results: The mean preoperative FRI was 3.4 (SD 1.1) and did not change during the volume optimization. The FRI was unchanged from starch during the first hour of surgery, whereas it decreased from 3.6 to 2.9 in response to Ringer´s lactate (P<0.01). The urine became more concentrated when the urinary excretion was below 100 ml/hour. Preoperative fluid retention (FRI ≥ 4.0), which is cut-off for renal fluid conservation consistent with a body fluid deficit amounting to 3% of the body weight, was present in 32% of the patients. Such retention increased the risk of a minor postoperative increase in serum creatinine (n=15, odds ratio 6.4) despite a higher creatinine clearance during the surgery (155 versus 80 ml/min; P<0.02). Conclusions: Ringer´s lactate, but not hydroxyethyl starch, decreased the urinary markers of fluid retention in the perioperative setting. Fluid retention increased the risk of a postoperative increase in serum creatinine.

Risk factors for renal dysfunction after total hip joint replacement; a retrospective cohort study.

Background and purpose of the studyRenal injury and dysfunction are serious complications after major surgery, which may lead to increased morbidity and mortality. The objective of our study was to identify the possible risk factors for renal dysfunction after total hip joint replacement surgery.MethodsA retrospective study was conducted among 599 consecutive primary hip joint replacements performed between January 2011 and December 2013. According to the RIFLE criteria, increased postoperative serum creatinine was considered indicative of postoperative renal injury. The Welch two-sample test, chi-square test, and Fisher exact test were used for statistical analysis.ResultsEighty-one patients (13.8 %) had significant moderate or severe postoperative renal dysfunction in which 10 patients (1.7 %) acquired severe and permanent renal impairment.ConclusionWe identified advanced age, hypertension, general anesthesia, high ASA scores, low intra-operative systolic BP, and prophylactic dicloxacillin as significant risk factors. Low baseline systolic BP, low baseline diastolic blood pressure, and hip fracture diagnosis were independent risk factors for postoperative increase in serum creatinine. Smoking, diabetes mellitus, high BMI, gender, and duration of surgery were not identified as significant risk factors.

Angiopoietin/Tie2 Dysbalance Is Associated with Acute Kidney Injury after Cardiac Surgery Assisted by Cardiopulmonary Bypass.

IntroductionThe pathophysiology of acute kidney injury (AKI) after cardiac surgery is not completely understood. Recent evidence suggests a pivotal role for the endothelium in AKI. In experimental models of AKI, the endothelial specific receptor Tie2 with its ligands Angiopoietin (Ang) 1 and Ang2 are deranged. This study investigates their status after cardiac surgery, and a possible relation between angiopoietins and AKI.MethodsFrom a cohort of 541 patients that underwent cardiac surgery, blood and urine was collected at 5 predefined time points. From this cohort we identified 21 patients who had at least 50% post-operative serum creatinine increase (AKI). We constructed a control group (n = 21) using propensity matching. Systemic levels of Ang1, Ang2, and sTie2 were measured in plasma and the AKI markers albumin, kidney injury molecule-1 (KIM-1) and N-acetyl-beta-D-glucosaminidase (NAG) were measured in the urine.ResultsAng2 plasma levels increased over time in AKI (from 4.2 to 11.6 ng/ml) and control patients (from 3.0 to 6.7 ng/ml). Ang2 levels increased 1.7-fold more in patients who developed AKI after cardiac surgery compared to matched control patients. Plasma levels of sTie2 decreased 1.6-fold and Ang1 decreased 3-fold over time in both groups, but were not different between AKI and controls (Ang1 P = 0.583 and sTie2 P = 0.679). Moreover, we found a positive correlation between plasma levels of Ang2 and urinary levels of NAG.ConclusionsThe endothelial Ang/Tie2 system is in dysbalance in patients that develop AKI after cardiac surgery compared to matched control patients.

Post-operative acute kidney injury in non-suprainguinal vascular surgery patients with a pre-operative history of hypertension.

Hypertension is an independent predictor of acute kidney injury (AKI) in non-cardiac surgery patients. There are a few published studies which report AKI following non-suprainguinal vascular procedures, but these studies have not investigated predictors of AKI, including anti-hypertensive medications and other comorbidities, in the hypertensive population alone. We sought to identify independent predictors of post-operative AKI in non-suprainguinal vascular surgery patients with a pre-operative history of hypertension. We performed univariate (chi-squared, or Fisher's exact testing) and multivariate (binary logistic regression) statistical analysis of prospectively collected data from 243 adult hypertensive patients who underwent non-suprainguinal vascular surgery (lower limb amputation or peripheral artery bypass surgery) at a tertiary hospital between 2008 and 2011 in an attempt to identify possible associations between comorbidity, acute pre-operative antihypertensive medication administration, and post-operative AKI (a post-operative increase in serum creatinine of ≥ 25 % above the pre-operative measurement) in these patients. The incidence of post-operative AKI in this study was 5.3 % (95 % Confidence Interval: 3.2-8.9 %). Acute pre-operative β-blocker administration was independently associated with post-operative AKI in non-suprainguinal vascular surgery patients with a pre-operative history of hypertension (Odds Ratio: 3.24; 95 % Confidence Interval: 1.03-10.25). The acute pre-operative administration of β-blockers should be carefully considered in non-suprainguinal vascular surgery patients with a pre-operative history of hypertension, in lieu of an increased risk of potentially poor post-operative renal outcomes.

Steroids In caRdiac Surgery (SIRS) trial: acute kidney injury substudy protocol of an international randomised controlled trial

IntroductionSteroids In caRdiac Surgery trial (SIRS) is a large international randomised controlled trial of methylprednisolone or placebo in patients undergoing cardiac surgery with the use of a cardiopulmonary bypass pump....

Acute kidney injury after coronary artery bypass grafting and long-term risk of myocardial infarction and death

BackgroundAcute kidney injury (AKI) after coronary artery bypass grafting (CABG) is associated with early mortality. Its impact on the risk of myocardial infarction (MI) over time and long-term mortality has not been well described. MethodsWe performed a nationwide population-based cohort study in 27,929 patients who underwent a first isolated CABG between 2000 and 2008 in Sweden. Acute kidney injury was divided into three categories based on the absolute increase in postoperative serum creatinine (sCr) concentration compared with the preoperative baseline: stage 1, sCr increase of 0.3 to 0.5mg/dL; stage 2, sCr increase of >0.5 to 1.0mg/dL and stage 3, sCr increase of ≥1.0mg/dL. ResultsThe overall incidence of postoperative AKI was 13%, 6.3% met the criterion for stage 1, 4.3% for stage 2 and 2.3% for stage 3. During a mean follow-up of 5.0years, there were 2119 (7.6%) MIs and 4679 (17%) deaths.Multivariable adjusted hazard ratios with 95% confidence intervals for MI were 1.35 (1.15 to 1.57), 1.80 (1.53 to 2.13) and 1.63 (1.29 to 2.07), in AKI stages 1, 2 and 3, respectively. The corresponding hazard ratios for all-cause mortality were 1.30 (1.17 to 1.44), 1.65 (1.48 to 1.83) and 2.68 (2.37 to 3.03), respectively. ConclusionsOur results show that AKI after CABG is associated with an increased long-term risk of MI and death.

Acute Kidney Injury after Valvular Heart Surgery and Early Changes in Cardiac Function and Structure

Background: Acute kidney injury (AKI) following heart surgery is associated with long-term risk of heart failure. It is not known if AKI following valvular heart surgery is associated with early changes in cardiac function or structure. Methods: A cohort study was conducted on 201 patients with AKI and 201 patients without AKI after valvular heart surgery, who were matched for age, sex, left ventricular function, and estimated glomerular filtration rate. AKI was defined as an increase in postoperative serum creatinine of ≥26 Vmol/l (≥0.3 mg/dl) or a relative increase of ≥50%. The two primary outcomes were changes in post- compared with preoperative left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD) assessed by echocardiography. Results: The mean age was 72 years, and 33% were female. Aortic valve surgery was the most frequent procedure. The mean time from surgery to the postoperative echocardiographic examination was 4.9 days (SD 3.7). There was no significant change in postoperative mean LVEF (-3.6 vs. -4.3%; p = 0.58) or mean LVEDD (-4.7 vs. -3.9 mm; p = 0.31) in patients with AKI compared to those without AKI. Conclusion: We found no acute changes in cardiac function or structure assessed by echocardiography in patients with AKI compared to those without AKI after valvular heart surgery. i 2014 S. Karger AG, Basel

Robot‐assisted partial nephrectomy vs laparoscopic cryoablation for the small renal mass: redefining the minimally invasive ‘gold standard’

To identify differences between the ablative and extirpative minimally invasive techniques of laparoscopic cryoablation (LC) and robot-assisted laparoscopic partial nephrectomy (RPN), respectively, in treating small renal tumours in terms of safety, peri-operative morbidity and early oncological outcomes. Between June 2008 and April 2012 56 patients underwent LC and from October 2010 to April 2012, 47 patients underwent RPN using the Da Vinci robotic platform (Intuitive Surgical, Sunnyvale, CA, USA). Data on intra-operative, postoperative and oncological outcomes were collected prospectively, and were analysed and compared for both groups. The median patient ages were 69 and 60 for the LC and RPN groups, respectively (P < 0.05). There was no significant difference in disease stage, but there was a significant difference in tumour size, with patients in the RPN group having larger tumours. The mean operating times were 146 and 159 min for the LC and RPN groups, respectively (P = 0.094) and the mean blood loss was 47 and 94 mL for the LC and the RPN groups, respectively (P = 0.251). The median length of hospital stay (1 day) was the same for both groups and the mean warm ischaemia time was 23 min in the RPN group. The marginal change in preoperative and 6-week postoperative renal function was recorded: the mean postoperative increase in serum creatinine was 5.4 mmol/L in the LC group and 9.2 mmol/L in the RPN group. Of the 47 patients in the RPN group, two (4.3%) were converted to laparoscopic radical nephrectomy because of difficulty in controlling bleeding during hilar dissection. Only two patients (3.6%) had recurrence in the LC group, both of whom were treated with re-cryoablation. A total of 5.4% of patients in the LC and 4.3% in the RPN group had Clavien grade I postoperative complications, one patient in the LC group had a Clavien grade II complication, while 1.8 and 4.3% of patients had Clavien IIIb in the LC and RPN groups, respectively. Our data confirm that LC is a successful, minimally invasive and safe treatment option for the management of small renal tumours, but the apparently similar characteristics of RPN suggest that an increasing proportion of patients, whatever their age or medical comorbidities, may be reasonably offered a robot-assisted extirpative procedure with the likely benefit of lower risk of local recurrence and need for retreatment.

Survival in patients with acute kidney injury requiring dialysis after coronary artery bypass grafting

The aim was a nationwide analysis of need for dialysis and survival in all patients who had coronary artery bypass grafting (CABG) in Sweden during 2002 up to 2008. Primary isolated CABG was performed in 28 220 patients without preoperative need for dialysis. Survival was analysed in patients suffering postoperative acute kidney injury requiring dialysis. Postoperative dialysis was needed in 162 patients (0.6%). Old age, female gender, reduced glomerular filtration rate (GFR), diabetes mellitus, peripheral vascular disease, chronic obstructive pulmonary disease, prior myocardial infarction, prior stroke and reduced left ventricular function were associated with need for dialysis. Only 0.3% of the patients with GFR>60 ml/min/1.73 m2 needed postoperative dialysis compared with 9.5% if GFR was <30 ml/min/1.73 m2. Sixteen of 54 patients (27%) with GFR<30 l/min/1.73 m2 and a ≥50% increase in postoperative serum creatinine needed dialysis. There were 42 deaths (26%) within 30 days in patients who needed dialysis and 1% if dialysis was not required. Early mortality was markedly higher in patients who required dialysis than in those without dialysis after multivariable adjustment for age, sex, diabetes mellitus, left ventricular function and GFR (odds ratio 19, 95% confidence interval 13-29). The corresponding risk of late death was 2-fold higher in patients who survived for 90 days and had required dialysis compared with those who did not (hazard ratio 2.4, 95% confidence interval 1.7-3.3). Five-year survival was 43 and 89%, respectively. The risk of death increased with age. Five-year survival after dialysis was 66% in patients younger than 65 years, but 32% in those aged over 70 years. Fifty-one per cent (14 of 27) of patients 80 years of age or older who required dialysis died early compared with 3% (68 of 2426) of those who did not (P<0.001). Nine survivors who needed dialysis developed end-stage renal disease. Need for dialysis after non-emergency was an uncommon serious complication associated with high early mortality and an increased risk of late death. Old age and impaired preoperative renal function were strong predictors of need for dialysis after CABG. Postoperative dialysis after CABG was a marker of poor outcome but could, in some patients, be life-saving.