Comment on “Use of Pre-operative Haemoglobin A1c to Predict Early Post-operative Renal Failure and Infection Risks in Patients Who are Not Diabetics and Undergoing Elective Off Pump Coronary Artery Bypass Graft Surgery”

Sir, We read with enthusiasm the article by Madhu and Patni published recently in the Annals of Cardiac Anaesthesia. The authors outline plasma HbA1c ≥6% as an independent predictor of postoperative renal failure in a prospective cohort of 200 non-diabetics undergoing elective off-pump coronary artery bypass grafting (CABG). This research group is congratulated for assessing a pertinent postoperative complication in a homogenous surgical cohort, excluding the confounding renal impact of extracorporeal circulation.[1] Nonetheless, there remain other important considerations while interpreting the index findings regarding peculiarly multifactorial acute kidney injury (AKI). Kim et al.[2] highlight that a coronary angiography (CAG) performed ≤ 7 days before off-pump CABG independently accentuates the propensity to postoperative AKI (multivariate-analysis OR: 3.00; 95% CI: 1.12-8.01, P value = 0.029). Thus, the lack of account for the preoperative CAG practices in the Madhu and Patni study, deserves special attention. Moreover, the absence of data on blood transfusion and low cardiac output syndrome in the present study is equally concerning, when literature associates the former with adverse renal outcomes.[3] To that end, the importance of quantifying the hemodynamic support can also not be undermined. Baysal et al.[4] delineate an enhanced predisposition to post-CABG morbid end-organ outcomes in the background of a vasoactive-inotropic score>5.5. Even in the specific context of the renal impact of deranged preoperative investigations, hypoalbuminemia has been described to be a pivotal risk factor for AKI following OPCAB surgery, as underlined by Lee et al.[5] Indeed, deliberation on these aspects in addition to being of general interest to the Journal readership, would more importantly guide future research in the corresponding subject. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.