University of Twente Student Theses


Performance development of off-pump coronary artery bypass surgeons

Olbrich, S.L. (2021) Performance development of off-pump coronary artery bypass surgeons.

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Abstract:Off-pump coronary artery bypass grafting (OPCAB) is a highly complex cardiac surgery procedure and requires considerable skill of the surgeon. To adequately evaluate performance (improvement) and create trainings, various outcome variables, their predictors and learning of OPCAB were investigated. This project is a single-institutional retrospective analysis of all surgeon, patient and procedural data of OPCAB cases between May 2015 and December 2019. Various outcome variables were visually and theoretically explored in their usefulness, three of which were chosen to represent accuracy and efficiency of the surgeon, and patient outcomes. The three chosen outcome variables were used to build Bayesian generalized linear mixed effects models, testing a total of 50 possible predictors. The development of performance over time was visually inspected, including CUSUM curves, and compared to the development of patient risk factors. Lowest systolic blood pressure (LSBP) was chosen as accuracy measure, operation duration for efficiency and a complication score built from all recorded complications for patient outcomes. Variance in LSBP could be explained for more than 70% by the built model, 9% of operation duration could be predicted by the final model, and no predictors could be found for the complication score. Surgeon specialisation, patient characteristics and the number of venous grafts and anastomoses were the factors influencing LSBP and operation duration the most. All outcome variables should be evaluated in the context of the surgical team and patient characteristics. The surgeon is never solely responsible for the outcomes. Hypotension is a useful measure for surgeon accuracy, as many covariates are commonly registered prediction was good. Operation duration appeared almost independent of most predictors and should be used with care. An unweighted score for patient complications should be avoided as in this case none of the 50 available predictors were able to predict its variance. OPCAB training should preferably take place in a safe environment for both patients and surgeons and should include as many differences in patients and scenarios as possible to adequately prepare the trainee for real cases. Venous grafts should be avoided due to intraoperative hypotension, longer operation duration and worse outcomes. Surgeons who decide to learn OPCAB should focus on that and perform most CABGs off-pump.
Item Type:Essay (Master)
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:77 psychology
Programme:Psychology MSc (66604)
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