Cross-clamp time is an independent predictor of mortality and morbidity in low- and high-risk cardiac patients

Abstract

Objectives: We sought to assess the effects of aortic cross-clamp time (XCL) on outcome following cardiac surgery in low- and high-risk patients. Methods: This is a retrospective review of prospectively collected departmental data of all patients who underwent cardiac surgery over 8-year period. Our cohort consisted of 3799 consecutive patients subdivided into low-risk (Euro SCORE < 6, n = 2691, 71%) and high-risk (Euro SCORE ≥ 6, n = 1108, 29%). Each class was further stratified into three groups based on their corresponding XCL time. Group 1 (XCL ≤ 60 min), group 2 (XCL > 60 but ≤ 90 min) and group 3 (XCL >90 min). Postoperative morbidity and in-hospital mortality were analysed. Results: Univariate analysis showed the following to be significantly associated with increased XCL time in both low- and high-risk patients: low cardiac output, prolonged ventilation time, renal complications, prolonged hospital stay, blood transfusion and increased mortality (p < 0.05). By using multiple logistic regression, aortic XCL time >60 min was independent risk factor for low cardiac output, prolonged ventilation, renal complication, blood transfusion, mortality and prolonged hospital stay in both groups. By using XCL time as a continuous variable, an incremental increase of 1 min interval in XCL time was associated with a 2% increase in mortality in both groups. Conclusion: Prolonged cross-clamp time significantly correlates with major post-operative morbidity and mortality in both low- and high-risk patients. This effect increases with increasing XCL time. Prior knowledge on this effect can help in preventing some of these complications.