The objective for the REQUEST study is to document how often the combination of high-frequency ultrasound imaging (HFUS) and Transit Time Flow Measurement (TTFM) performed with Medistim’s VeriQ C or MiraQ devices will change the surgical procedure. The REQUEST surgical coronary artery bypass grafting (CABG) protocol includes ultrasound scanning of the aorta, conduits, target coronary vessels and anastomoses, as well as TTFM graft assessment.

More than 1 000 CABG patients were included in this prospective, multicenter, registry study between April 2015 and December 2017. Seven leading cardiac surgery centers from Europe, USA and Canada, led by Coordinating Investigator, Professor David Taggart from the University of Oxford, participated. On October 20th, Professor Taggart presented the final results from this study.

The final results showed that 25% of the patient population had one or more surgical changes made to the surgical strategy based on imaging and flow data. Of the sub-populations that went through aorta scanning and coronary target scanning, 10 % and 20 % of the patients had changes in the surgical strategy, respectively. Graft assessment with TTFM was performed in 99 % of the patients, with a result of 3 % anastomotic revision rate in 7 % of the patients. These results may be compared with previously published data showing about 4-5 % anastomotic revision rate in about 10 % of the patients. Furthermore, the in-hospital outcomes showed a remarkably low mortality rate of 0.6 % and stroke/TIArate of 1 %.

“The final results confirmed the findings from the interim analysis presented in May. In the hands of expert cardiac surgeons, and using state-of-the-art surgical procedures, HFUS for surgical guidance and TTFM for graft assessment led to a 3 % revision rate of the anastomosis and very low level of in-hospital mortality and stroke rates”, commented Professor David Taggart.  “One of the striking findings is that without routine assessment in the operating room, most of these aorta and graft problems would have not been detected until after the patient had left the operating room. These results indicate that combining TTFM and HFUS in order to guide surgery, verify graft patency and to avoid or correct surgical problems intraoperatively, may play an important role in our continued endeavors to improve CABG surgery and its outcomes to the benefit of our patients. It should therefore become a standard of care.”

«Medistim’s interest in this study has been to investigate and document the clinical value of the combined use of TTFM and HFUS”, says Medistim President and CEO, Kari E. Krogstad. “With these final results, we believe that the REQUEST study has provided new insights that may positively impact clinical outcomes and change clinical practice going forward. The data will support initiatives for further guideline recommendations as well as reimbursement. We are very much encouraged by these final results, and look forward to further analysis and results to become available from this vast patient material in the future, in order to continue learning and developing this surgical procedure.”