Preoperative blood morphology and incidence of acute kidney injury after on-pump coronary artery bypass grafting – a single-center preliminary report

Abstract

IntroductionAcute kidney injury (AKI) after coronary artery bypass grafting (CABG) performed in cardiopulmonary bypass (CPB) may complicate the postoperative course and has a negative impact on outcome. In some cases, postoperative AKI develops in spite of normal baseline creatinine concentration and estimated glomerular filtration rate (eGFR).AimTo examine whether there is any association between the preoperative blood morphology and incidence of post-operative AKI.Material and methodsThe study involved 62 consecutive patients with the mean age of 64.0 ±7.4 years who underwent CABG in CPB. Before surgery, blood morphology and biochemistry were analyzed. Patients with eGFR below 60 ml/min/1.73 m2 were excluded. After the operation, parameters of renal function were checked systematically. Acute kidney injury was defined according to the Acute Kidney Injury Network (AKIN) classification.ResultsTwenty-one (33.9%) patients presented AKI (group AKI), although in the majority of them (n = 16) it was temporary and medical management was enough to cure AKI. Only in 1 (1.6%) case was renal replacement therapy necessary. In group AKI, patients’ preoperative hemoglobin concentration (8.46 ±0.72 mM/l), red blood cell count (4.51 ±0.39 × 1012/l) and hematocrit (0.40 ±0.04) were significantly lower (p < 0.05) than in group C (9.07 ±0.57 mM/l; 4.78 ±0.36 × 1012/l; 0.43 ±0.03, respectively). Interestingly, the baseline parameters of renal function were comparable between groups.ConclusionsHemoglobin concentration and red blood cell counts close to the lower limit of the normal range may enable identification of patients at risk of AKI early after CABG in CPB among individuals with normal preoperative biochemical parameters of renal function.

Risk factor analysis and risk prediction model of cardiac surgery-associated acute kidney injury after Da Vinci robotic cardiac surgery

“…CSA-AKI after cardiac surgery is also closely related to surgical factors, and studies have shown that HBG concentration during CPB [40,41], hematocrit [42], and CPB time [43,44] are independent risk factors for CSA-AKI after cardiac surgery. This study also showed that operation time, CPB time, aortic cross-clamp time, and intraoperative blood product intake were associated with CSA-AKI after robotic cardiac surgery, and exclusion of confounding factors showed that operation time ≥ 300 min was an independent risk factor for postoperative CSA-AKI, which was consistent with previous studies.…”

Acute Kidney Injury following Cardiopulmonary Bypass: A Challenging Picture

“…Another tool for predicting the risk of AKI and improving individualized patient care is focused on identifying the genetic risk factors that might be involved [11], a decreased hemoglobin concentration during CPB surgery is an independent risk factor for AKI, with an effect cut-off value of <9 g/dL (<5.6 mmol/L) (OR, 1.16 per 1 g/dL decrease; 95% CI, 1.05-1.31; P = 0:018), which is not altered by systemic arterial oxygen saturation and pressure values. Other studies also support that the low hemoglobin concentration even within the normal range, as well as the nadir hemoglobin level, is associated with increased incidence of CPB-associated AKI [53,54]. Strategies that improve the hemoglobin concentration, such as the conservative use of red blood cell (RBC) transfusion, are recommended, since circulating free iron-mediated nephrotoxicity with hemolysis and free hemoglobin are likely to lead to AKI in patients undergoing cardiac surgery with CPB.…”