Acute kidney injury in septua- and octogenarians after cardiac surgery

Coronary artery bypass grafting in octogenarians: an Australian experience

BACKGROUND

The aims of this study were to describe early and mid-term morbidity and mortality in octogenarian patients undergoing CABG, to determine if outcomes are comparable to younger patients undergoing the same procedure.

METHODS

We conducted a retrospective analysis of the first 901 patients who underwent cardiac surgery at a large newly established tertiary hospital in Western Australia from February 2015 to September 2019. Inclusion criteria involved all patients undergoing coronary artery bypass grafting. Exclusion criteria included patients who underwent concomitant valve or aortic procedure.

RESULTS

From a cohort of 901 patients, 37 octogenarian patients underwent CABG. Octogenarian patients had a higher rate of post-operative transfusion 35.1% versus 21.4% (P = 0.048), a higher rate of post-op acute kidney injury 40.5% versus 17.2% (P < 0.0001), a higher rate of post-operative atrial arrythmia requiring treatment 40.5% versus 22.5% (P = 0.011) and higher rate of return to theatre (13.5% versus 4.7%, P = 0.018), with bleeding/tamponade being the most likely reason (10.8% versus 2.7%). Octogenarian patients had a longer post-operative length of stay (LOS) with a median LOS of 10 versus 7 days (P < 0.0001). There was no increase in hospital readmission rate, in-hospital mortality or 1 year mortality in octogenarian patients. 24-month and 36-month survivals were 95.2% and 89.6% in octogenarians and 95.3% and 91.5% in the younger group.

CONCLUSIONS

Despite an increase in post-operative morbidity and LOS, there was no difference in hospital readmission, in-hospital mortality or 1 year mortality in octogenarian patients who underwent CABG. CABG is safe and remains an important management option for these patients.

Free Hemoglobin Ratio as a Novel Biomarker of Acute Kidney Injury After On-Pump Cardiac Surgery: Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a high risk of postoperative acute kidney injury (AKI). Due to limitations of current diagnostic strategies, we sought to determine whether free hemoglobin (fHb) ratio (ie, levels of fHb at the end of CPB divided by baseline fHb) could predict AKI after on-pump cardiac surgery.

METHODS

This is a secondary analysis of a randomized controlled trial comparing the effect of nitric oxide (intervention) versus nitrogen (control) on AKI after cardiac surgery (NCT01802619). A total of 110 adult patients in the control arm were included. First, we determined whether fHb ratio was associated with AKI via multivariable analysis. Second, we verified whether fHb ratio could predict AKI and incorporation of fHb ratio could improve predictive performance at an early stage, compared with prediction using urinary biomarkers alone. We conducted restricted cubic spline in logistic regression for model development. We determined the predictive performance, including area under the receiver-operating-characteristics curve (AUC) and calibration (calibration plot and accuracy, ie, number of correct predictions divided by total number of predictions). We also used AUC test, likelihood ratio test, and net reclassification index (NRI) to compare the predictive performance between competing models (ie, fHb ratio versus neutrophil gelatinase-associated lipocalin [NGAL], N-acetyl-β-d-glucosaminidase [NAG], and kidney injury molecule-1 [KIM-1], respectively, and incorporation of fHb ratio with NGAL, NAG, and KIM-1 versus urinary biomarkers alone), if applicable.

RESULTS

Data stratified by median fHb ratio showed that subjects with an fHb ratio >2.23 presented higher incidence of AKI (80.0% vs 49.1%; P = .001), more need of renal replacement therapy (10.9% vs 0%; P = .036), and higher in-hospital mortality (10.9% vs 0%; P = .036) than subjects with an fHb ratio ≤2.23. fHb ratio was associated with AKI after adjustment for preestablished factors. fHb ratio outperformed urinary biomarkers with the highest AUC of 0.704 (95% confidence interval [CI], 0.592-0.804) and accuracy of 0.714 (95% CI, 0.579-0.804). Incorporation of fHb ratio achieved better discrimination (AUC test, P = .012), calibration (likelihood ratio test, P < .001; accuracy, 0.740 [95% CI, 0.617-0.832] vs 0.632 [95% CI, 0.477-0.748]), and significant prediction increment (NRI, 0.638; 95% CI, 0.269-1.008; P < .001) at an early stage, compared with prediction using urinary biomarkers alone.

CONCLUSIONS

Results from this exploratory, hypothesis-generating retrospective, observational study shows that fHb ratio at the end of CPB might be used as a novel, widely applicable biomarker for AKI. The use of fHb ratio might help for an early detection of AKI, compared with prediction based only on urinary biomarkers.

Risk Factors and Outcome of Acute Kidney Injury after Isolated CABG Surgery: a Prospective Cohort Study

BACKGROUND

Acute kidney injury (AKI) is a frequent event after cardiac surgery with increased mortality and morbidity. We explored frequency, risk factors, and associated morbidity and mortality of AKI after isolated coronary artery bypass grafting (CABG) surgery at a single institution.

METHODS

All consecutive adults undergoing CABG surgery from March 2013 to October 2016 were assessed for development and severity of AKI based on Acute Kidney Injury Network (AKIN) criteria. The patients were also investigated regarding their need for renal replacement therapy (RRT), predictive risk factors, and associated outcomes, including duration of mechanical ventilation, mortality, intensive care unit (ICU) and hospital length of stay.

RESULTS

Of 1737 patients in the study, 275 (15.8%) developed AKI. Twenty-five (12.8%) cases required RRT. Patients with AKI had longer ventilation time, ICU and hospital length of stay (P<0.001). Mortality rates were 28 (10.2%) and 22 (1.5%) in patients with and without AKI, respectively (P<0.001). There was a strong association between advanced age (aOR=1.016, 95% CI=1.002-1.030, P=0.028), diabetes (aOR=1.36, 95% CI=1.022-1.809, P=0.035), on-pump surgery (aOR=2.63, 95% CI=1.543-4.483, P<0.001), transfusion of more than 1 unit of red blood cells (aOR=2.154, 95% CI=1.237-3.753, P=0.007), and prolonged mechanical ventilation and development of AKI (aOR=2.697, 95% CI=1.02407.071, P<0.001). AKI was seen less frequently in those with opium abuse (aOR=0.613, 95% CI=0.409-0.921, P=0.018).

CONCLUSION

We demonstrated that advanced age, diabetes, on-pump surgery, red blood cell transfusion, and prolonged mechanical ventilation were independent positive risk factors for the development of AKI after isolated CABG while opium abuse was a protective factor.

The Relationship Between Age and Chronic Kidney Disease in Patients Undergoing Pancreatic Resection

BACKGROUND

Severe chronic kidney disease (CKD) predicts adverse outcomes in patients undergoing pancreatectomy, but the impact of milder CKD is unknown. Additionally, some authors have suggested that, due to physiologic changes of aging, CKD is over-diagnosed in patients above age 65.

METHODS

Patients undergoing pancreatectomy for malignancy from 2005 to 2014 were identified from the National Surgical Quality Improvement Program. Primary outcomes were all-cause mortality and major complication, defined as myocardial infarction, cardiac arrest, stroke, venous thromboembolism, respiratory failure, deep surgical site infection, pneumonia, acute kidney injury, coma > 24 h, or re-operation occurring within 30 days of surgery.

RESULTS

The mean age of 16,173 participants was 66 (range 18-90). Median preoperative creatinine was 0.80 mg/dL (0.10-11.0), and median preoperative eGFR was 86.36 mL/min/1.73m² (2.98-182.2). Mortality and major complication occurred in 3 and 23% of patients, respectively. In adjusted analyses, CKD stages 2 (adjusted odds ratio (aOR) 1.24, 95% confidence interval (CI) 1.10-1.40), 3a (aOR 1.50, 95% CI 1.24-1.82), 3b (aOR 1.56, 95% CI 1.19-2.06), and 4 (aOR 2.17, 95% CI 1.25-3.76) were associated with increased major complication, and CKD stage 4 was associated with increased mortality (aOR 2.68, 95% CI 1.10-6.56). Age did not influence the relationship between CKD and either outcome.

CONCLUSION

CKD of any stage was associated with an increased risk of postoperative major complication, and severe CKD was associated with increased mortality among patients undergoing pancreatectomy for malignancy. These associations were not diminished in elderly patients. Our findings could inform preoperative counseling and decision-making.

Incidence and outcomes of acute kidney injury in octogenarians in Jordan

Objective

Improvements in the health care system, resulted in a greater number of geriatric patients diagnosed with acute kidney injury (AKI). We evaluated the incidence and outcome of AKI in octogenarians, as studies in the Middle-East region are few; moreover, treatment approaches, in addition to medical decisions, may require special consideration for advanced age to improve the outcomes.

Results

At King Abdullah II teaching and referral hospital, we recruited patients aged 80–90 years who were admitted to the medical floor between January 2010 and December 2013. Patients were followed-up for at least 1 year after discharge.850 patients were admitted during the study period. Of these, 135 were excluded from our analysis. The most common admission diagnoses were uncontrolled diabetes mellitus and acute coronary syndrome. AKI occurred in 216 patients (30.2%). Using the acute kidney injury network classification; stage 1, stage 2, and stage 3 disease were present in 59, 17.5, and 23.5% of patients, respectively. Of the 115 patients who died before discharge (16.1%), 87 (75.6%) had developed AKI. Hypertension, the use of angiotensin receptor blockers and non-steroidal anti-inflammatory drugs, heart failure, and exposure to radiologic contrast media were significant risk factors for AKI.

Persistent kidney injury at hospital discharge after cardiac surgery with cardiopulmonary bypass in patients with normal preoperative serum creatinine and normal estimated glomerular filtration rate

OBJECTIVE

Acute kidney injury is a serious complication after cardiac surgery. Although it resolves in most cases, a significant portion of patients persistently have raised creatinine values at hospital discharge. These patients are at greater risk for developing chronic kidney disease and mortality. Therefore, the present study aimed to ascertain risk factors of persistent acute kidney injury after cardiac surgery in patients with normal preoperative renal function.

DESIGN

Prospective cohort study.

SETTING

Tertiary heart centers.

PARTICIPANTS

2,181 adult cardiac surgical patients, predominantly Asian.

INTERVENTIONS

Cardiac surgery between August 2008 and July 2012.

MEASUREMENTS AND MAIN RESULTS

The incidence of acute kidney injury, as defined by the Acute Kidney Injury Network stage 1 criteria, was 21.7%. At discharge, 10.5% of these patients had persistent kidney injury, which was defined as a ≥ 26.4 μmol/L (≥ 0.3 mg/dL) difference between preoperative and discharge creatinine levels and/or a 50% rise in serum creatinine. These patients were more likely to be aged ≥ 70 years (relative risk = 2.232, 95% confidence interval = 1.326-3.757, p = 0.003), have a higher peak postoperative creatinine value within 48 hours (relative risk = 1.007, 95% confidence interval = 1.004-1.010, p<0.001), and have lower hemoglobin on intensive care unit arrival (relative risk = 0.759, 95% confidence interval = 0.577-0.998, p = 0.048).

CONCLUSIONS

Age ≥ 70 years, higher peak postoperative creatinine within 48 hours, and lower hemoglobin on intensive care unit arrival are associated with persistent acute kidney injury. Strategies to improve hemoglobin on intensive care unit arrival potentially can reduce persistent acute kidney injury. The authors recommend that patients aged ≥ 70 years undergo further renal evaluation for better risk stratification.

Predictors of acute kidney injury in geriatric patients undergoing total knee replacement surgery

BACKGROUND

Few studies have focused on patients' characteristics that affects acute kidney injury (AKI) after total knee replacement surgery (TKR).

OBJECTIVES

The primary objective of this retrospective study was to identify patients' characteristics associated with AKI after TKR.

PATIENTS AND METHODS

Between January 2008 and December 2009, 659 patients with a mean age of 67.1 years (range, 39-99) underwent TKA at Regional Hospital Knee and Hip Institute. Retrospective chart review was done to identify patients' characteristics that were associated with AKI after TKR. Logistic regression was used to evaluate AKI.

RESULTS

AKI occurred in 21.9% of patients. AKI risk decreased between 2008 and 2009 (odds ratio, 0.55; 95% CI, -0.37 to 0.82) but increased with age (P < 0.001), diabetes mellitus (DM), and angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) use (OR, -1.6; 95% CI, -1.0 to 2.5; and OR, -1.5, 95% CI, -1.0 to 2.3, respectively). However, the effects of DM and ACEI/ARB use were not independent; when both were included in the regression model, neither was statistically significant, and both ORs were smaller than combined OR.

CONCLUSIONS

When examined separately, both DM and preoperative ACEI/ARB use increased the risk of AKI; however these factors were correlated and were not independent predictors of significantly increased risk. Patients with DM have higher tendency to develop AKI and hence, preoperative renal risk stratification should be done in all patients with DM.

Perioperative intravascular volume replacement and kidney insufficiency

Perioperative acute kidney injury (AKI) occurrence is probably increased in recent years due to the increased level of complexity of surgical procedures and severity of illness of surgical patients. Perioperative AKI has a multifactorial aetiology (preoperative co-morbidities such as diabetes, heart failure and chronic kidney disease, emergent surgery, exposure to nephrotoxic drugs, haemodynamic instability, hypothermia, inflammatory response to surgery, hospital-acquired infections and abdominal compartment syndrome). However, fluid choice for perioperative volume replacement might have a major role in perioperative AKI, as administration of crystalloid solutions, colloids or haemoderivates has the potential for kidney injury. This review focusses on the issue of fluid replacement quality and quantity and their association with renal dysfunction.

Advanced age affects the outcome-predictive power of RIFLE classification in geriatric patients with acute kidney injury

The RIFLE (risk, injury, failure, loss, and end-stage) classification is widely used to gauge the severity of acute kidney injury, but its efficacy has not been formally tested in geriatric patients. To correct this we conducted a prospective observational study in a multicenter cohort of 3931 elderly patients (65 years of age or older) who developed acute kidney injury in accordance with the RIFLE creatinine criteria after major surgery. We studied the predictive power of the RIFLE classification for in-hospital mortality and investigated the potential interaction between age and RIFLE classification. In general, the survivors were significantly younger than the nonsurvivors and more likely to have hypertension. In patients 76 years of age and younger, RIFLE-R, -I, or -F classifications were significantly associated with increased hospital mortality in a stepwise manner. There was no significant difference, however, in hospital mortality in those over 76 years of age between patients with RIFLE-R and RIFLE-I, although RIFLE-F patients had significantly higher mortality than both groups. Thus, the less severe categorizations of acute kidney injury per RIFLE classification may not truly reflect the adverse impact on elderly patients.