Impact of intraoperative direct coronary scanning using 15MHz high frequency epicardial ultrasound
Tokyo Medical and Dental University, Tokyo, Japan.
OBJECTIVE: There is concern about the increased risk of anastomosis construction errors in Off-pump coronary artery bypass grafting (OPCAB)because the suturing process is technically more demanding than surgery on the arrested heart. Transit time flow measurement (TTFM) is probably most commonlyused in intraoperative evaluation. Unfortunately, flow rate and wave form provided by TTFM are poor indicators of the geometry of anastomosis. Since2010, We introduced 15MHz high frequency epicardial ultrasound (ECUS) and have been investigating the efficacy of ECUS as intraoperative evaluation in OPCAB surgery. We would like to demonstrate the usefulness of 15MHz high frequency ECUS in this video.
METHODS: In OPCAB surgery, we directly scanned the location and the condition of coronary artery before anastomosis. On the basis of these images, we decided optimal anastomosis sites and surgical strategy whether to perform on-lay patch grafting or not. After completion of anastomosis, we evaluated the anastomosis quality using ECUS besides TTFM.
RESULTS: ECUS could provide more detailed information including the depth of coronary artery, and the intraluminal calcified plaque. In case with intra-myocardial coronary artery, we could directly approach the coronary artery avoiding unnecessary dissection or accidental injury of right ventricle. With the precise images of intraluminal calcified plaque, we could make surgical decision whether to perform on-lay patch grafting or skip anastomosis before dissection of coronary artery. ECUS was also useful to assess the anastomosis geometry immediately after anastomosis. In one case, we could detect intimal flap of internal thoracic artery (ITA) at the anastomosis site and restricted flow pattern with color Doppler Flow mapping. We revised the anastomosis with increase in graft flow (10ml/min to 36ml/min).
CONCLUSIONS: Next to TTFM, ECUS can easily be employed as a complementary quality control method to provide information about target anastomosis site, bypass graft function and anastomosis geometry. High frequency ECUS was considered an indispensable modality which can improve the quality of OPCAB surgery.
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