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Relationship between fractional flow reserve and graft patency after coronary artery bypass grafting
Michiko Ishida1, Hiroshi Ishikawa2, Yoshiyuki Takami2
1Department of Cardiovascular Surgery, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan. m-ishida@fujita-hu.ac.jp.
Insights
Fractional flow reserve (FFR) helps predict graft failure in coronary artery bypass grafting (CABG). Gray-zone FFR values (0.75-0.80) in bypassed arteries may indicate graft issues, especially when no pre-operative ischemia is present.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Vascular Physiology
Background:
- Coronary artery bypass grafting (CABG) is susceptible to graft failure, including the string phenomenon and occlusion, particularly in moderately stenosed arteries.
- Fractional flow reserve (FFR) is a physiological measure used to assess the functional significance of coronary artery stenosis.
Purpose of the Study:
- To investigate the impact of FFR on the efficacy of CABG in preventing graft failure.
- To determine if FFR values correlate with graft patency and the occurrence of the string phenomenon or occlusion.
Main Methods:
- A cohort of 48 patients undergoing CABG between 2013 and 2017 had FFR measured pre-operatively.
- Graft patency, graft flow, and myocardial ischemia were evaluated post-procedure for 25 grafts in 23 patients.
- Stenosis severity, FFR, and graft outcomes were analyzed in relation to pre- and post-procedure ischemia.
Main Results:
- Three internal thoracic artery grafts exhibited the string sign, and two saphenous vein grafts were occluded, all associated with moderate stenosis (50-75%).
- Grafts with the string sign were linked to target coronary arteries with gray-zone FFR values (0.75-0.80).
- No significant difference in graft flow was found between failed and successful grafts; patients with graft failure showed no postoperative ischemia.
Conclusions:
- Internal thoracic artery grafts to coronary arteries with gray-zone FFR values may be prone to the string phenomenon.
- Graft failure might be attributed to the absence of pre-operative ischemia in the target coronary artery territory.
- FFR is a valuable tool for pre-operative ischemic evaluation, aiding in graft selection and influencing revascularization success.
Background:
Bypass for moderately stenosed coronary arteries may cause graft failure (string phenomenon or occlusion). We examined the effects of fractional flow reserve (FFR) on the efficacy of coronary artery bypass grafting (CABG) in preventing graft failure.
Methods:
Between January 2013 and December 2017, 48 patients underwent CABG after FFR was measured. Twenty-five grafts in 23 patients were evaluated for graft patency after the procedure. We studied stenosis of native coronary arteries, FFR, graft flow, graft patency, and the presence of pre-procedure and post-procedure myocardial ischemia.
Results:
Three internal thoracic arteries showed the string sign, and two saphenous vein grafts showed occlusion. All target coronary arteries for these grafts had moderate (50-75%) stenosis. Of the 25 grafts, five failed, and 20 were successful. All grafts with the string sign had been bypassed for target coronary arteries with the gray-zone FFR value (0.75-0.80). No difference in graft flow was observed between the failed and successful grafts. Patients with graft failure had no postoperative myocardial ischemia in target areas despite graft condition.
Conclusion:
Internal thoracic artery graft for coronary arteries with the gray-zone FFR value may exhibit the string phenomenon. We believe that graft failure occurred because the target area had no ischemia before CABG. FFR is useful in pre-operative ischemic evaluation including scintigraphy and will influence the success of revascularization, including the selection of grafts.
