Death in low-risk cardiac surgery revisited

Background: A systematic review of low-risk death has been shown successful in identifying system weaknesses. The aim was to analyse early mortality in low-risk patients undergoing cardiac surgery and to determine the cause of death, classify if they were unavoidable or potentially preventable as a result of technical or system errors. Methods: We included all low-risk patients who underwent cardiac surgery at our institution from 1 September 2009 to 31 August 2019. In patients operated between 2009 and 2011, we defined low risk as an additive European System for Cardiac Operative Risk Evaluation (EuroSCORE) I less than or equal to 3, and from 2012 and onwards as a EuroSCORE II less than or equal to 1.5. The medical records for the patients who died within 30 days of surgery were thoroughly examined and the cause of death was classified as cardiac or non-cardiac. Furthermore, deaths were categorised as not preventable, preventable (technical error) or preventable (system error). Results: During the study period 3103 low-risk patients underwent surgery, and 11 patients died within 30 days of the operation (0.35%). Six of these (55%) were classified as preventable and five non-preventable. Four of the preventable deaths were classified as technical errors and two were due to system errors. Conclusions: A repeated systematic review of deaths in patients with a low preoperative risk showed that a majority of deaths were preventable, and therefore potentially avoidable. Similar to the previous assessment at our unit, mortality was very low and failure to communicate remains a modifiable factor that should be addressed.