iFR-guided vs angiography-guided coronary artery bypass grafting: 36 months follow up

Abstract

AIMS:

to evaluate prospectively graft patency, major adverse cardiovascular and cerebrovascular events and clinical outcomes at 36-months follow-up comparing instantaneous wave–free ratio (iFR) guided to angiography guided coronary artery bypass grafting (CABG).

METHODS AND RESULTS:

iFR-guided versus angiography-guided CABG - is a prospective, single blinded, randomized controlled trial. 110 patients, referred for the CABG because of multivessel disease, were enrolled into a study. iFR was performed to every vessel diagnosed with intermediate stenosis (50-75%). Randomisation 1:1 divided patients into two groups: either angiography (51), either iFR values based CABG (59) with exception to left anterior descending artery – all grafted despite iFR value. 26 out of 59 (44 %) iFR-CABG group patients were diagnosed with one or two vessels disease instead of multivessel. After iFR was unblinded in iFR-CABG group, 9 out of 59 (15.3 %) patients/cardiac surgeons refused to perform CABG as a choice of treatment. Coronary computed tomography angiography (CT) was performed at 36 months follow-up. The primary endpoint of this part of the study was to determine the rate of graft occlusion or hypoperfusion at 36 months follow-up. Secondary endpoint was - major adverse cardiac and cerebrovascular event (MACCE) rate. At 36-months follow-up CT scan was performed in 78 patients (78%). Screening revealed, that 90,0% patent left internal mammary artery - left anterior descending artery grafts were diagnosed when iFR was < 0,85 and just 29,4% when iFR was >0,9 (p<0,001). When iFR in left anterior descending artery was < 0,85, compared to iFR > 0,85, graft patency was 90.0% vs 41.9% respectively, (p<0,005). Combining all greater saphenous vein grafts (attached to diagonal, marginal and right coronary arteries) in one group, patent graft rate in iFR-guided group comparing to angiography-guided one was 90,2% vs 70,3%, respectively, (p=0,046). There were no statistically significant difference (p=0,48) between two groups in terms of major adverse cardiovascular and cerebrovascular events: 14 events were determined in iFR-CABG group and 10 in angiography-CABG group, (p=0,48). Ethics approval number BE-2-89 (10.12.2018).

CONCLUSION:

performing iFR in multivessel coronary artery disease patients may identify fewer significant stenoses, reducing the need for CABG. The number of patent grafts was statistically bigger in iFR-CABG group during 36-months follow up comparing to angiography-based CABG group. During the 36-month follow-up (evaluated 100pts. cases), no significant differences were found between the two groups in terms of clinical outcomes or major adverse cardiovascular and cerebrovascular events.