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Microcirculatory dysfunction plays a crucial role in renal ischemia/reperfusion (IR)-induced injury. Dexmedetomidine was reported to ameliorate IR-induced acute kidney injury. This study investigated the effects of dexmedetomidine on renal microcirculation after IR-induced acute kidney injury in rats. In total, 50 rats were randomly allocated to the following five groups (10 in each group): Sham, Control‒IR, Dex (dexmedetomidine) ‒Sham, Dex‒IR, and IR‒Dex group. The microcirculation parameters included total small vessel density, perfused small vessel density (PSVD), proportion of perfused small vessels, microvascular flow index, and tissue oxygen saturation (StO 2 ) were recorded. The repeated measures analysis showed that PSVD on renal surface was higher in the Dex‒IR group than in the Control‒IR group (3.5 mm/mm 2 , 95% confidence interval [CI] 0.6 to 6.4 mm/mm 2 , P = 0.01). At 240 min, StO 2 on renal surface was lower in the Control‒IR group than in the Sham group (- 7%, 95% CI - 13 to - 1%, P = 0.021), but StO 2 did not differ significantly among the Sham, Dex‒IR, and IR‒Dex groups. Our results showed that pretreatment with dexmedetomidine improved renal microcirculation in rats with IR-induced acute kidney injury. However, the adverse effects of low mean arterial pressure and heart rate might offset the protective effect of dexmedetomidine on organ injury.

Objectives: Acute kidney disease (AKD), the transition of acute kidney injury to chronic kidney disease, has major clinical significance. Whether mineralocorticoid receptor antagonist will afford target organ protection during this critical stage remains ill-defined., Methods: Using a population-based cohort database from January 1999 to July 2011, we identified 7252 AKD patients with hypertension, of whom 2255 were treated with mineralocorticoid receptor antagonist (user) and 4997 were treated by other antihypertensive medication (nonuser). Outcomes were all-cause mortality, major adverse cardiovascular events (MACE), and long-term dialysis dependence., Results: With median 13.37 months of follow-up (IQR 30.53 months), users had a lower incidence of dialysis dependence than nonusers (138.3/1000 person-years vs. 267.2/1000 person-years). After matching users and nonusers (1 : 1) with mortality as a competing risk, Cox proportional hazards analyses showed that mineralocorticoid receptor antagonist therapy was associated with lower risk of dialysis dependence [subhazard ratio (sHR) = 0.83, 95% confidence interval (CI) 0.74-0.93, P = 0.001] but higher risk of hyperkalemia (sHR 1.15, 95% CI, 1.04-1.26, P = 0.005) compared with nonusers. Nonetheless, the risks for all-cause mortality [adjusted hazard ratio (aHR) 1.07, 95% CI 0.98-1.17, P = 0.109] and MACE (sHR 1.08, 95% CI 0.95-1.23, P = 0.210) were similar., Conclusion: Although carrying the risk of hyperkalemia, mineralocorticoid receptor antagonist therapy is associated with similar risk for incident MACE and death; however, with lower risk of long-term dialysis dependence. Our findings have the potential to provide target-organ protection insights in AKD patients with hypertension.

Introduction: The adverse consequences of a non-dialysis-requiring acute kidney injury (AKI) are unclear. This study aimed to assess the long-term prognoses for critically ill patients experiencing a non-dialysis-requiring AKI., Methods: This retrospective observational cohort study investigated non-dialysis-requiring AKI survivors in surgical intensive care units between January 2002 and June 2010. All longitudinal post-discharge serum creatinine measurements and information regarding end-stage renal disease (ESRD) and death were collected. We assessed the long-term outcomes of chronic kidney disease (CKD), ESRD and all-cause mortality beyond discharge., Results: Of the 922 identified critically ill patients with a non-dialysis-requiring AKI, 634 (68.8%) patients who survived to discharge were enrolled. A total of 207 patients died after a median follow-up of 700.5 days. The median intervals between the onset of the AKI and the composite endpoints "stage 3 CKD or death", "stage 4 CKD or death", "stage 5 CKD or death", and "ESRD or death" were 685, 1319, 1743, and 2048 days, respectively. This finding shows a steady long-term decline in kidney function after discharge. Using the multivariate Cox proportional hazard model, we found that every 1 mL/min/1.73 m2 decrease from baseline estimated glomerular filtration rate (eGFR) of individuals who progressed to stage 3, 4, and 5 CKD increased the risks of long-term mortality by 0.7%, 2.3%, and 4.1%, respectively (all p < 0.05). This result indicates that the mortality risk increased significantly in a graded manner as kidney function declined from the baseline eGFR to advanced stages of CKD during the follow-up period., Conclusions: In critically ill patients who survive a non-dialysis-requiring AKI, there is a need for continuous monitoring and kidney function protection beyond discharge.

Whether preoperative proteinuria associates with adverse renal outcomes after cardiac surgery is unknown. Here, we performed a secondary analysis of a prospectively enrolled cohort of adult patients undergoing coronary artery bypass grafting (CABG) at a medical center and its two affiliate hospitals between 2003 and 2007. We excluded patients with stage 5 CKD or those who received dialysis previously. We defined proteinuria, measured with a dipstick, as mild (trace to 1+) or heavy (2+ to 4+). Among a total of 1052 patients, cardiac surgery-associated acute kidney injury (CSA-AKI) developed in 183 (17.4%) patients and required renal replacement therapy (RRT) in 50 (4.8%) patients. In a multiple logistic regression model, mild and heavy proteinuria each associated with an increased odds of CSA-AKI, independent of CKD stage and the presence of diabetes mellitus (mild: OR 1.66, 95% CI 1.09 to 2.52; heavy: OR 2.30, 95% CI 1.35 to 3.90). Heavy proteinuria also associated with increased odds of postoperative RRT (OR 7.29, 95% CI 3.00 to 17.73). In summary, these data suggest that preoperative proteinuria is a predictor of CSA-AKI among patients undergoing CABG.

Summary: Background: Septic acute kidney injury (AKI) is a common complication in intensive care units (ICU), it and portends a higher risk of morbidity and death than nonseptic AKI. However, its outcome and prognostic factors among elderly postoperative patients remain unknown. We aimed to determine the risk factors and predictors of mortality among postoperative elderly patients (≥ 65 years) with septic AKI requiring acute dialysis. Methods: The study protocol was based on that of a clinical cohort study of renal failure patients in the database of the National Taiwan University Surgical ICU Acute Renal Failure (NSARF) Study Group. From January 2002 to July 2009, patients (aged > 18 years) with postoperative AKI requiring renal replacement therapy (RRT) were recruited for this study. Each case of septic AKI before operation was identified and patients with end-stage renal disease were excluded. Results: A total of 292 postoperative patients with septic AKI requiring dialysis were identified during the study period. The mean (SD) age was 65.9 (11.9) years and 68.2% were men. Abdominal surgery was the most common type of surgery (42.8%), followed by cardiovascular (28.8%) and chest surgery (15.4%). The most common indications for RRT in this study cohort were azotemia in 223 patients (76.4%) and fluid overload in 62 patients (21.2%); 92 (31.5%) patients had one indication, 170 (58.2%) had two indications, and 30 (10.3%) had more than three indications. The elderly patients (those ≥ 65 years) had anemia, underwent abdominal surgery, and received dialysis for fluid overload more frequently than the young adults. By contrast, the young adults were more likely to present with shock requiring vasopressor use and have abnormal liver functions. In the elderly subgroup, the outcome was found to be associated with mechanical ventilator use, but not with disease severity, comorbidities, types of surgery and the indication for dialysis. Conclusions: The hospital mortality of postoperative elderly patients with septic AKI was more than 60% and was not affected by age. Mechanical ventilator use was the major risk factor and prognostic factor for elderly patients in this clinical setting. [Copyright &y& Elsevier]

(1) Background: Norepinephrine (NE) is the first-line vasoactive agent used in septic shock patients; however, the effect of norepinephrine on dialysis-required septic acute kidney injury (AKI-D) patients is uncertain. (2) Methods: To evaluate the impact of NE on 90-day mortality and renal recovery in septic AKI-D patients, we enrolled patients in intensive care units from 30 hospitals in Taiwan. (3) Results: 372 patients were enrolled and were divided into norepinephrine users and non-users. After adjustment by Inverse probability of treatment weighted (IPTW), there was no significant difference of baseline comorbidities between the two groups. NE users had significantly higher 90-day mortality rate and using NE is a strong predictor of 90-day mortality in the multivariate Cox regression (HR = 1.497, p = 0.027) after adjustment. The generalized additive model disclosed norepinephrine alone exerted a dose–dependent effect on 90-day mortality, while other vasoactive agents were not. (4) Conclusion: Using norepinephrine in septic AKI-D patients is associated with higher 90-day mortality and the effect is dose-dependent. Further study to explore the potential mechanism is needed. [ABSTRACT FROM AUTHOR]