Effect of pre-operative hemoglobin level on early outcomes in patients undergoing urgent coronary artery bypass grafting

Abstract

Background

Low hemoglobin (Hb) is progressively frequent sign in patients undergoing cardiac surgery. Although, anemia is potentially treatable condition prior to surgery, numerous studies have proven that low hemoglobin level is linked with higher rate of morbidity and mortality. The proportion of pre-operative low hemoglobin level and its significant effectiveness on outcomes of patients subjected to urgent coronary artery bypass is not well investigated.

Aim of the work

this study was conducted to examine the implications of preoperative anemia and adverse outcomes in patients referred for urgent coronary artery bypass grafting (CABG) in a tertiary care, university affiliated center.

Methods

128 consecutive patients undergoing urgent CABG between January 2011 and June 2013 were included. Our cohort was grouped according to pre-operative hemoglobin (HB) concentration and divided into two main groups: Anemic patient's group n = 51 (HB < 13 gm/dl in men and <12 gm/dl in women) and Non-anemic patients' group n = 77 (HB > 13 gm/dl in men and >12 gm/dl in women). Information from those patients was collected on a regular basis. Pre-operative and operative data points (including demographics, diabetes mellitus, hypertension, smoking, myocardial infarction, NYHA class, pre-operative EF, pre-operative ES diameter, pre-operative ED diameter, preoperative creatinine, preoperative PASP, prior PCI, thrombolysis, number of grafts, associated procedures (aortic valve surgery, mitral valve surgery, VSD, and ascending aorta replacement).

Results

Postoperative adverse outcomes in both groups was defined as the presence any of the following complications either alone or in combination such as post-operative mortality, rewiring for infection, AF, stroke, acute kidney injury, need of intra-aortic balloon pump(IABP), ECMO, cerebral hemorrhage, RBCs transfusion, plasma transfusion, ICU and hospital stay. In our population, limited to patients undergoing urgent CABG, 40% of patients were anemic and we demonstrated that anemic patients are at risk of rewiring for infection and this was statistically significant (p-value = 0.02).

Conclusions

Anemic patients had significantly worse outcome in terms rewiring for infection in patients undergoing urgent CABG. Further, comprehensive prospective studies are required to justify the proportional significance of pre-operative low hemoglobin level, other comorbidities and peri-operative blood transfusion in patients going through urgent CABG.