Microalbuminuria is associated with high adverse event rate following cardiac surgery

Urinary albumin creatinine ratio associated with postoperative delirium in elderly patients undergoing elective non-cardiac surgery: A prospective observational study

Introduction

The blood‐brain barrier (BBB) disruption contributes to postoperative delirium, but cost‐effective and non‐invasive assessment of its permeability is not practicable in the clinical settings. Urine albumin to creatinine ratio (UACR), reflecting systemic vascular endothelial dysfunction, may be a prognostic and predictive factor associated with postoperative delirium. The aim was to analyze the relationship between UACR and postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Materials and methods

Through stratified random sampling, a cohort of 408 individuals aged 60 years and older scheduled for elective non‐cardiac surgery were included between February and August 2019 in the single‐center, prospective, observational study. The presence of delirium was assessed using the Confusion Assessment Method (CAM) or Confusion Assessment Method for the ICU (CAM‐ICU) on the day of surgery, at 2 h after the surgery ending time and on the first 3 consecutive days with repeated twice‐daily, with at least 6‐h intervals between assessments. Urine samples were collected on one day before surgery, and 1st day and 3rd day after surgery. The primary outcome was the presence of postoperative delirium, and association of the level of UACR with postoperative delirium was evaluated with unadjusted/adjusted analyses and multivariable logistic regression.

Results

Postoperative delirium was observed in 26.75% (107 of 400) of patients within 3 days post‐surgery. UACR‐Pre (OR, 1.30; 95% CI, 1.14–1.49, p < 0.001), UACR‐POD1 (OR, 1.20; 95% CI, 1.13–1.27, p < 0.001), and UACR‐POD3 (OR, 1.14; 95% CI, 1.08–1.20, p < 0.001) between the delirium and non‐delirium groups show a significant difference, even after adjusting for age, education levels, and other factors.

Conclusion

As the marker of endothelial dysfunction, the high perioperative UACR value may be linked to the postoperative delirium in elderly patients undergoing elective non‐cardiac surgery.

Pre-operative proteinuria, postoperative acute kidney injury and mortality: A systematic review and meta-analysis

OBJECTIVE

To investigate the association of pre-operative proteinuria with postoperative acute kidney injury (AKI) development as well as the requirement for a renal replacement therapy (RRT) and mortality at short-term and long-term follow-up.

BACKGROUND

Postoperative AKI is associated with surgical morbidity and mortality. Pre-operative proteinuria is potentially a risk factor for postoperative AKI and mortality. However, the results in literature are conflicting.

METHODS

We searched PubMed, Embase, Scopus, Web of Science and Cochrane Library from the inception through to 3 June 2020. Observational cohort studies investigating the association of pre-operative proteinuria with postoperative AKI development, requirement for RRT, and all-cause mortality at short-term and long-term follow-up were considered eligible. Using inverse variance method with a random-effects model, the pooled effect estimates and 95% confidence interval (CI) were calculated.

RESULTS

Twenty-eight studies were included. Pre-operative proteinuria was associated with postoperative AKI development [odds ratio (OR) 1.74, 95% CI, 1.45 to 2.09], in-hospital RRT (OR 1.70, 95% CI, 1.25 to 2.32), requirement for RRT at long-term follow-up [hazard ratio (HR) 3.72, 95% CI, 2.03 to 6.82], and long-term all-cause mortality (hazard ratio 1.50, 95% CI, 1.30 to 1.73). In the subgroup analysis, pre-operative proteinuria was associated with increased odds of postoperative AKI in both cardiovascular (OR 1.77, 95% CI, 1.47 to 2.14) and noncardiovascular surgery (OR 1.63, 95% CI, 1.01 to 2.63). Moreover, there is a stepwise increase in OR of postoperative AKI development when the quantity of proteinuria increases from trace to 3+.

CONCLUSION

Pre-operative proteinuria is significantly associated with postoperative AKI and long-term mortality. Pre-operative anaesthetic assessment should take into account the presence of proteinuria to identify high-risk patients.

PROSPERO REGISTRATION

CRD42020190065.

Microalbuminuria assessment after thoracic surgery: Early identification of complication risks

INTRODUCTION

Microalbuminuria (MA) is considered a reflection of systemic capillary leak and an early marker of acute stress reaction to the surgical insult, proportional to the severity of the initiating condition and predictive of the individual response to surgical stress.

OBJECTIVES

We conducted a prospective study to assess for the variation of MA within 4 days after thoracic surgery. We correlated observed MA levels with both their respective PaO₂ /FiO₂ respiratory ratio and the onset of postoperative complications.

METHODS

This single-centre study enrolled 255 consecutive patients having an American Society of Anaesthesiologists (ASA) score ≤ 3. The mean age was 62 years with 67% male. All patients were scheduled for elective pulmonary resection. MA was measured in urine samples as the albumin-to-creatinine ratio (A/C), prior to, at and after extubation up to 96 hours. PaO₂ /FiO₂ was measured at extubation and on the first postoperative day.

RESULTS

Overall, preoperative A/C levels resulted normal, with a significant average increase at extubation which peaked 6 hours later (P < 0.001). Larger postoperative A/C increases were observed in patients who developed postoperative complications, compared to those without these complications (P < 0.019). Moreover, patients undergoing major open pulmonary resections had larger postoperative A/C increases, compared to those undergoing minor video-assisted thoracic surgery resections (P < 0.006). At the time of extubation, A/C was inversely related to the PaO₂ /FiO₂ ratio (r = -0.25; P = 0.038). Peak A/C > 61 mg/g (P = 0.0003) was associated with postoperative cardio-pulmonary complications (OR 3.85; P = 0.003).

CONCLUSION

Within 6 hours after extubation, MA assessment may be a rapid and relatively inexpensive method for better predicting perioperative risk in an ASA score ≤ 3 population.

Preoperative Albuminuria and Intraoperative Chloride Load: Predictors of Acute Kidney Injury Following Major Abdominal Surgery

Background: Postoperative Acute Kidney Injury (AKI) is a common and serious complication associated with significant morbidity and mortality. While several pre- and intra-operative risk factors for AKI have been recognized in cardiac surgery patients, relatively few data are available regarding the incidence and risk factors for perioperative AKI in other surgical operations. The aim of the present study was to determine the risk factors for perioperative AKI in patients undergoing major abdominal surgery. Methods: This was a prospective, observational study of patients undergoing major abdominal surgery in a tertiary care center. Postoperative AKI was diagnosed according to the Acute Kidney Injury Network criteria within 48 h after surgery. Patients with chronic kidney disease stage IV or V were excluded. Logistic regression analysis was used to evaluate the association between perioperative factors and the risk of developing postoperative AKI. Results: Eleven out of 61 patients developed postoperative AKI. Four intra-operative variables were identified as predictors of AKI: intra-operative blood loss (p = 0.002), transfusion of fresh frozen plasma (p = 0.004) and red blood cells (p = 0.038), as well as high chloride load (p = 0.033, cut-off value > 500 mEq). Multivariate analysis demonstrated an independent association between AKI development and preoperative albuminuria, defined as a urinary Albumin to Creatinine ratio ≥ 30 mg·g⁻¹ (OR = 6.88, 95% CI: 1.43–33.04, p = 0.016) as well as perioperative chloride load > 500 mEq (OR = 6.87, 95% CI: 1.46–32.4, p = 0.015). Conclusion: Preoperative albuminuria, as well as a high intraoperative chloride load, were identified as predictors of postoperative AKI in patients undergoing major abdominal surgery.

Association of Pre-Operative Albuminuria with Post-Operative Outcomes after Coronary Artery Bypass Grafting

The effect on post-operative outcomes after coronary artery bypass graft(CABG) surgery is not clear. Among 17,812 patients who underwent CABG during October 1,2006-September 28,2012 in any Department of US Veterans Affairs(VA) hospital, we identified 5,968 with available preoperative urine albumin-creatinine ratio(UACR) measurements. We examined the association of UACR<30, 30–299 and >=300 mg/g with 30/90/180/365-day and overall all-cause mortality, and hospitalization length >10 days, and with acute kidney injury(AKI). Mean ± SD baseline age and eGFR were 66 ± 8 years and 77 ± 19 ml/min/1.73 m², respectively. 788 patients(13.2%) died during a median follow-up of 3.2 years, and 26.8% patients developed AKI(23.1%-Stage 1; 2.9%-Stage 2; 0.8%-Stage 3) within 30 days of CABG. The median lengths of stay were 8 days(IQR: 6–13 days), 10 days(IQR: 7–14 days) and 12 days(IQR: 8–19 days) for groups with UACR < 30 mg/g, 30–299 mg/g and ≥300 mg/g, respectively. Higher UACR conferred 72 to 85% higher 90-, 180-, and 365-day mortality compared to UACR<30 mg/g (odds ratio and 95% confidence interval for UACR≥300 vs. <30 mg/g: 1.72(1.01–2.95); 1.85(1.14–3.01); 1.74(1.15–2.61), respectively). Higher UACR was also associated with significantly longer hospitalizations and higher incidence of all stages of AKI. Higher UACR is associated with significantly higher odds of mortality, longer post-CABG hospitalization, and higher AKI incidence.

Post-operative acute kidney injury and five-year risk of death, myocardial infarction, and stroke among elective cardiac surgical patients: a cohort study

INTRODUCTION

The prognostic impact of acute kidney injury (AKI) on long-term clinical outcomes remains controversial. We examined the five-year risk of death, myocardial infarction, and stroke after elective cardiac surgery complicated by AKI.

METHODS

We conducted a cohort study among adult elective cardiac surgical patients without severe chronic kidney disease and/or previous heart or renal transplant surgery using data from population-based registries. AKI was defined by the Acute Kidney Injury Network (AKIN) criteria as a 50% increase in serum creatinine from baseline level, acute creatinine rise of ≥26.5 μmol/L (0.3 mg/dL) within 48 hours, and/or initiation of renal replacement therapy within five days after surgery. We followed patients from the fifth post-operative day until myocardial infarction, stroke or death within five years. Five-year risk was computed by the cumulative incidence method and compared with hazards ratios (HR) from a Cox proportional hazards regression model adjusting for propensity score.

RESULTS

A total of 287 (27.9%) of 1,030 patients developed AKI. Five-year risk of death was 26.5% (95% CI: 21.2 to 32.0) among patients with AKI and 12.1% (95% CI: 10.0 to 14.7) among patients without AKI. The corresponding adjusted HR of death was 1.6 (95% CI: 1.1 to 2.2). Five-year risk of myocardial infarction was 5.0% (95% CI: 2.9 to 8.1) among patients with AKI and 3.3% (95% CI: 2.1 to 4.8) among patients without AKI. Five-year risk of stroke was 5.0% (95% CI: 2.8 to 7.9) among patients with AKI and 4.2% (95% CI: 2.9 to 5.8) among patients without AKI. Adjusted HRs were 1.5 (95% CI: 0.7 to 3.2) of myocardial infarction and 0.9 (95% CI: 0.5 to 1.8) of stroke.

CONCLUSIONS

AKI, within five days after elective cardiac surgery, was associated with increased five-year mortality and a statistically insignificant increased risk of myocardial infarction. No association was seen with the risk of stroke.