Background: An increasing number of patients with severe coronary artery disease (CAD)  are at high operative risk due to advanced age, severe comorbidities, complex coronary anatomy and reduced left ventricular ejection fraction. Consequently, these high-risk patients undergo more often high-risk coronary interventions (HRI). One major complication after percutaneous interventions is acute kidney injury (AKI) due to multimorbidity, nephrotoxicity of contrast agents and potential systemic malperfusion during HRI. Therefore, patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF) are thought to be at higher risk for AKI occurrence, greater severity and initiation of renal replacement therapy (RRT). The aim of this study was to analyze the role of LVEF as a predictor for AKI severity in patients undergoing HRI. 

Methods and results: Between 2016 and 2019 a total of 520 patients underwent HRI. All patients treated with extracorporeal life support were excluded. Out of them, 474 patients (91.2%) were eligible for trial participation. Patients were analyzed for occurrence of AKI and severity of AKI according current KDGIO guidelines. For further investigation patients with AKI were split in three subgroups based on LVEF (LVEF <40%, 40-49%, ≥50%) and reviewed for differences. AKI was observed in 14.8% (n=70; 71.4% male; mean age 72.5 years). AKI was more frequent in patients with severely reduced LVEF (LVEF <40%: 29.2% vs.  LVEF 40-49%: 19% vs. LVEF ≥50%: 8.1%; p<0.001).  Subgroup analyses of AKI patients with severely reduced LVEF showed less AKI stage 1 (LVEF <40%: 67.9% vs. LVEF 40-49%: 85% vs. LVEF ≥50%: 86.4%; p=0.203) but more severe AKI (AKI stage 2: LVEF <40%: 14.3% vs. LVEF 40-49%: 5.0% vs. LVEF ≥50%: 0%, p=0.136; AKI stage 3: LVEF <40%: 17.9% vs. LVEF 40-49%: 10% vs. LVEF ≥50%: 13.6%, p=0.741). The dissemination of baseline chronic kidney disease (CKD) ≥ stage 3 did not differ significantly between the three subgroups. Additionally, the risk of intrahospital death was statistically significant higher for those with AKI and severely reduced LVEF (LVEF <40%: 43.5% vs. LVEF 40-49%: 11.1% vs. LVEF ≥50%: 7.1%; p=0.01).

Conclusion: Patients with severely reduced LVEF appear to be at higher risk for relevant AKI even though baseline CKD was not high. Prospective studies need to be enrolled to verify observations and develop preventive precautions.