Analysis of mortality in low-risk patients undergoing coronary artery bypass grafting

AIM The aims of this study were to determine the early mortality rate in low-risk coronary artery bypass graft (CABG) patients and examine the causes of death, to identify problems that could be avoided in future surgeries. METHODS All low-risk patients (EuroSCORE ≤ 2) who died after CABG were included. Their peri-operative information was meticulously studied by internal and independent external reviewers to identify causes of death, which were classified as: cardiac or non-cardiac; and a further division as: (1) non-preventable, (2) preventable (technical error), and (3) preventable (system error). RESULTS Early mortality was 0.93% (24/2570). Eleven patients (45.8%) were classified as preventable deaths. In six of them the main problem was identified as graft thrombosis, which was secondary to a technical error of either the harvesting or anastomosis of the left internal mammarian artery. There were also five system errors identified as delays in the treatment of an identified and potentially reversible problem. CONCLUSION Correction of technical and system errors, such as harvesting of the left internal mammarian artery, haemostasis during surgery, and establishing standard protocols for the transfer of patients from ward to intensive care units will eventually lead to improvement in both the quality of care and patient outcomes, even in low-risk groups.