CARDIAC SURGERY RESIDENTS’ LEARNING CURVE OF TRANSIT TIME FLOWMETRY AND HIGH FREQUENCY EPICARDIAL ULTRASOUND IN CORONARY SURGERY: THE LEARNERS STUDY

Background and Aim: Transit-time flowmetry (TTFM) and high frequency epicardial ultrasound (HFUS) allow intraoperative quality control in coronary surgery. Although excellent performance has been reported, their use is still limited due to a perceived complexity of the learning curve. Methods: The learning curve of cardiac surgery residents without previous experience was evaluated. A scoring system based on specific items was developed and an expert senior surgeon was used as benchmark. Upon reaching a pre-specified threshold score, residents were considered autonomous in the procedures and left the study. Results: The study is still ongoing. To date, 34 anastomoses in 14 patients (15 arterial grafts, 19 venous grafts) have been studied by 8 residents (4.3 anastomoses/resident). The pre-specified combined TTFM+HFUS cutoff score was reached by 3 out of 8 residents after a mean number of 2 cases (5.3 anastomoses/resident). The remaining 5 trainees who have not yet reached the primary end-point have studied 8 patients for a total number of 18 anastomoses (3.6 anastomoses/trainee). When analyzed separately, the secondary end-point TTFM cutoff score was reached more frequently (5/8 trainees, 2.6 anastomoses/trainee) than that of HFUS (3/8 trainees, 4.3 anastomoses/trainee). Conclusions: Preliminary data suggest that the TTFM and HFUS learning curve is not as steep as expected. Epicardial ultrasound could be less manageable than flowmetry but, with adequate pre-surgical training, residents can manage quickly. If the data were confirmed, the perceived complexity of TTFM and HFUS should no longer be claimed as a cause of a lack of use of these intraoperative procedures.