Long-term kidney outcomes of acute kidney injury in myocardial infarction with cardiogenic shock and elective coronary surgery

Abstract Background Acute kidney injury (AKI) is a common and serious complication of acute myocardial infarction with cardiogenic shock (AMI-CS), substantially increasing both short- and long-term mortality (1–3). However, it remains uncertain whether long-term kidney dysfunction results from intrinsic kidney injury or whether AKI merely reflects the severity of haemodynamic compromise during the acute event. Purpose To determine whether AKI affects long-term kidney function independent of acute illness severity by comparing the 10-year incidence of chronic kidney disease (CKD) and mortality after AKI in patients with AMI-CS versus those with chronic ischemic heart disease undergoing elective coronary artery bypass grafting (CABG). Methods This retrospective cohort study included AMI-CS patients (2010–2017) and CABG patients (2000–2024) from two tertiary cardiac centres. To assess long-term effects, only patients surviving at least 100 days were included in the analyses. AKI was classified using KDIGO criteria. In AMI-CS, severe AKI was defined as AKI requiring continuous kidney replacement therapy (CKRT); incident CKD was ascertained through the National Patient Registry (ICD-10). In CABG, severe AKI was defined by KDIGO stage 3; incident CKD by sustained eGFR 60 mL/min/1.73 m² on two measurements ≥90 days apart using regional laboratory data. Patients with pre-existing CKD at hospital admission were excluded from CKD analysis. Primary outcome was 10-year incident CKD, analysed using competing risk regression with death as a competing event. Secondary outcome was all-cause mortality. Models were adjusted for age, sex, body mass index, diabetes, hypertension, and previous myocardial infarction. Results The study included 1,473 AMI-CS patients (mean age 66 years, 76% male; 44% developed AKI, 26% severe AKI) and 9,547 CABG patients (median age 67 years, 79% male; 22% developed AKI, 0.8% severe AKI). Among 100-day survivors (AMI-CS: n=741; CABG: n=8,466), 10-year mortality was higher in patients with severe AKI than in those without AKI (AMI-CS: 53% vs. 39%; CABG: 52% vs. 21%). When analysing competing risk for incident CKD, severe AKI yielded aHR 3.97 (95% CI 2.97–6.74) in AMI-CS patients and aHR 3.43 (95% CI 2.45–4.80) in CABG patients compared to no AKI. In CABG patients, even mild–moderate AKI (stage 1–2) was associated with increased CKD risk, but not in AMI-CS patients. The relationship between AKI severity and cumulative CKD incidence is shown in Figure 1. Conclusions Among 100-day survivors, severe AKI is associated with a significantly increased risk of developing CKD in both AMI-CS and CABG patients, together with substantially higher long-term mortality compared with patients without AKI. These findings suggest that intrinsic kidney injury may independently drive long-term kidney dysfunction. Enhanced CKD surveillance is warranted for all high-risk cardiac patients experiencing AKI, regardless of clinical context.