Acute Kidney Injury After Coronary Artery Bypass Grafting and Long-Term Risk of End-Stage Renal Disease

Abstract

Background-Acute kidney injury (AKI) is a common complication after coronary artery bypass grafting (CABG) and is associated with adverse outcomes. However, the relationship between AKI after CABG and the long-term risk of endstage renal disease (ESRD) is unknown. Methods and Results-This study included 29 330 patients who underwent primary isolated CABG in Sweden between2000 and 2008. AKI was classified according to the Acute Kidney Injury Network (AKIN) classification: stage 1, >0.3 mg/dL (>26 μmol/L) or 50% to 100% increase; stage 2, 100% to 200% increase; and stage 3, >200% increase from the preoperative to postoperative serum creatinine level. Cox proportional hazards regression analysis was used to calculate hazard ratios with 95% confidence intervals for ESRD in AKIN stage 1 and stage 2 to 3. Postoperative AKI occurred in 13% of patients. During a mean follow-up of 4.3±2.4 years, 123 patients (0.4%) developed ESRD, including 50 (1.6%) in AKIN stage 1, 29 (5.2%) in AKIN stage 2 to 3, and 44 (0.2%) without AKI after CABG. After multivariable adjustment, the hazard ratio for ESRD was 2.92 (95% confidence interval, 1.87-4.55) for AKIN stage 1 and 3.81 (95% confidence interval, 2.14-6.79) for AKIN stage 2 to 3. Conclusions-This nationwide study of patients who underwent CABG found that a small increase in the postoperative serum creatinine level was associated with an almost 3-fold increase in the long-term risk of ESRD after adjustment for a number of confounders, including preoperative renal function. According to Recommended Therapies (SWEDEHEART) registry. 15This registry includes all patients who have undergone coronary angiography, percutaneous coronary intervention, or cardiac surgery in Sweden since 1992, with complete coverage of the whole country. Agreement between information in the registry and the medical records was reported to be between 93% and 97%. 15 The present study included all patients who underwent CABG in Sweden between 2000 and 2008. The exclusion criteria are shown in Figure 1. Patients were excluded if they had undergone prior cardiac surgery, had undergone vascular or valvular surgery concurrently with CABG, had missing preoperative or postoperative s-Cr levels, had undergone surgery within 24 hours of the decision to operate, had a preoperative estimated glomerular filtration rate (eGFR) of <15 mL·min, or were dialysis dependent before surgery. Diabetes mellitus, hypertension, chronic obstructive pulmonary disease, and hyperlipidemia were recorded if patients were receiving ongoing pharmacological treatment for these conditions.Patients were usually reviewed by a cardiologist a few weeks after surgery and then followed up by their family doctor.The study complied with the guidelines of the Declaration of Helsinki and was approved by the regional ethics review board in Stockholm. The postoperative s-Cr level recorded in the SWEDEHEART registry is the highest level measured during the postoperative hospital stay. In a subgroup of 483 patients who underwent CABG at 1 center (Karolinsk...

Acute kidney injury after cardiac surgery: a preventable event?

“…A recently published singlecenter retrospective study conducted in 767 adult critically ill patients, mainly cardiac and postoperative patients, showed that the incidence of AKI was high in this cohort (51.9%) and that the mortality rate increased with progression of the AKI stage [1]. A similar high incidence of AKI and its association with poor outcomes have also been reported in post-CVS patients in several studies [2][3][4][5].…”

Long-Term Risk of Progressive Chronic Kidney Disease in Patients with Severe Acute Kidney Injury Requiring Dialysis after Coronary Artery Bypass Surgery

“…A recent multi-center Swedish study of 29,330 post-CABG patients confirmed that the ESRD risk was greater in patients with more severe AKI. The adjusted hazard ratio (95% confidence interval) for ESRD was 2.92 (1.87, 4.55) for AKIN stage 1 and 3.81 (2.14, 6.79) for AKIN stages 2 and 3 [25]. …”

Janus Face of Coronary Artery Disease and Chronic Kidney Disease

“…James et al observed a graded increase in risk of ESRD, which varied by the severity of AKI, among patients who underwent coronary angiography and developed AKI 10. In a nationwide cohort of patients who underwent coronary artery bypass grafting, even a small postoperative increase in serum creatinine was associated with an increase in the long‐term risk of ESRD 11. In this study, Sabe et al tested this possibility by including a time‐varying covariate for coronary revascularization in the model and did not find any significant impact on CKD progression, but this secondary analysis of TREAT cannot completely exclude the possibility that AKI could have contributed to the risk of ESRD in this population 7…”