TCT-515 Myocardial Blood Flow Distribution Derived From CCTA, Myocardium at Risk, and Revascularization Completeness in FASTTRACK CABG

Abstract

Background
There is no objective, quantitative, and universal definition of complete revascularization with invasive or noninvasive angiography.

Methods
Patients in the FASTTRACK CABG trial (n = 114), CABG guided solely by coronary computed tomography angiography (CCTA), and fractional flow reserve derived from CCTA (FFRCT) were included. Left ventricular percentage myocardial blood flow distribution (LV%MYO) was computed in the 16 SYNTAX coronary segments. Given each point of the fixed myocardial weighing factor represents 16.7% (1/6) of blood flow, the myocardial weighing factor of each coronary segment = 6 × LV%MYO. Graft patency and topographic adequacy were assessed at 30-day follow-up CCTA (n = 96). By subtracting the LV%MYO of segments anastomosed to a nonstenotic graft from the pre-CABG global LV%MYO, the post-CABG residual LV%MYO was obtained.

Results
FFRCT and LV%MYO were analyzed in 106 patients, with 53 having at least 1 total occlusion. The fixed myocardial weighing factors differ significantly from the weighing factors derived from LV%MYO. (Figure 1) The pre-CABG global LV%MYO and post-CABG residual LV%MYO were 70.1 ± 18.8% and 14.0 ± 15.3%, respectively. Residual LV%MYO ≤10% was achieved in 42 patients (43.8%). Among the 106 coronary segments not revascularized, the main reason was the operator’s decision not to graft, whereas graft occlusion accounted for 22.6% (24/106).

Conclusions
LV%MYO enables clinicians to objectively quantify the myocardium at risk of each coronary segment and to prospectively predict and retrospectively assess the revascularization completeness.