Incidence, risk factors and prediction of post-operative acute kidney injury following cardiac surgery for active infective endocarditis: an observational study

Abstract

IntroductionCardiac surgery is frequently needed in patients with infective endocarditis (IE). Acute kidney injury (AKI) often complicates IE and is associated with poor outcomes. The purpose of the study was to determine the risk factors for post-operative AKI in patients operated on for IE.MethodsA retrospective, non-interventional study of prospectively collected data (2000–2010) included patients with IE and cardiac surgery with cardio-pulmonary bypass. The primary outcome was post-operative AKI, defined as the development of AKI or progression of AKI based on the acute kidney injury network (AKIN) definition. We used ensemble machine learning (“Super Learning”) to develop a predictor of AKI based on potential risk factors, and evaluated its performance using V-fold cross validation. We identified clinically important predictors among a set of risk factors using Targeted Maximum Likelihood Estimation.Results202 patients were included, of which 120 (59%) experienced a post-operative AKI. 65 (32.2%) patients presented an AKI before surgery while 91 (45%) presented a progression of AKI in the post-operative period. 20 patients (9.9%) required a renal replacement therapy during the post-operative ICU stay and 30 (14.8%) died during their hospital stay. The following variables were found to be significantly associated with renal function impairment, after adjustment for other risk factors: multiple surgery (OR: 4.16, 95% CI: 2.98-5.80, p<0.001), pre-operative anemia (OR: 1.89, 95% CI: 1.34-2.66, p<0.001), transfusion requirement during surgery (OR: 2.38, 95% CI: 1.55-3.63, p<0.001), and the use of vancomycin (OR: 2.63, 95% CI: 2.07-3.34, p<0.001), aminoglycosides (OR: 1.44, 95% CI: 1.13-1.83, p=0.004) or contrast iodine (OR: 1.70, 95% CI: 1.37-2.12, p<0.001). Post-operative but not pre-operative AKI was associated with hospital mortality.ConclusionsPost-operative AKI following cardiopulmonary bypass for IE results from additive hits to the kidney. We identified several potentially modifiable risk factors such as treatment with vancomycin or aminoglycosides or pre-operative anemia.

Anemia Is a Risk Factor for Acute Kidney Injury and Long-Term Mortality in Critically Ill Patients

“…Because AKI frequently develops in the ischemic conditions, anemia can be one of reasons for the high incidence of AKI in hospital-admitted patients (i.e., 1 in 5 adults and 1 in 3 children patients) (Susantitaphong et al 2013). Previous studies in several clinical settings (Karkouti et al 2009;Legrand et al 2013;Sickeler et al 2014) and our ICU results support the relationship between anemia and AKI. Thus, it is helpful to monitor serum hemoglobin or anemia to prevent worse outcomes of AKI.…”

Minor Postoperative Increases of Creatinine Are Associated With Higher Mortality and Longer Hospital Length of Stay in Surgical Patients

“…17,42,43 The duration of intraoperative CPB has thus been linked to the incidence and severity of postcardiac surgery AKI. 8,15,[44][45][46][47] However, the fact that AKI in noncardiac surgery patients has a more profound impact on mortality and HLOS suggests that "low-grade AKI" caused by CPB is likely an event that the kidneys can recover from in most instances, whereas "low-grade AKI" without the use of CPB indicates a more severe form of intrinsic injury to the kidneys. Indeed, these findings alert to the fact that clinicians should take subclinical increases of creatinine levels in general surgery patients very seriously.…”

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

“…Factors associated with an increased risk of renal injury in patients with IE were investigated [6]. Intraoperative variables included the surgery duration, CPB and aortic cross-clamp times, fluid balance, transfusion requirements, and vasoconstrictor/inotropic medication requirements.…”

“…Surgery with cardiopulmonary bypass (CPB), however, is inevitably accompanied by numerous factors that contribute to acute kidney injury (AKI) [3]. An early, exaggerated inflammatory response with oxidative stress and the preoperative use of nephrotoxic antibiotics further predispose patients with IE to renal impairment [4–6]. Indeed, AKI affects up to 60% of patients with IE undergoing cardiac surgery [6], and the occurrence and severity of AKI have been indisputably associated with mortality and poor outcomes [7].…”