Pre-CABG assessment of coronary stenosis with FFR-CT predicts future graft failure

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): National Institute of Cardiology grant. Objectives To evaluate, whether a pre-CABG coronary computed tomography based FFR (FFR-CT) result at the site of a future anastomosis would predict the graft failure in patients undergoing CABG. Background Functional guidance of surgical coronary revascularization remains debatable. Recently FFR-CT is recognized as suitable for the diagnosis of vessel-specific ischemia. Methods In 43 patients (mean age 65.14y (± 9.91), 15 women) who had CCTA performed less than 6 months prior to the isolated CABG, follow-up CCTA were acquired >12 months post CABG procedure (at median of 903[IQR:468–1669] days). Based on the pre-CABG CCTA, FFR-CT values were simulated. On the basis of follow-up CCTA the anastomosis sites and the graft patency were determined. The graft failure was defined as either its stenosis >50% or occlusion. Results 98 (44 saphenous, 54 LIMA/RIMA) grafts were assessed. 18 graft from 16 patients were dysfunctional on follow-up CCTA. FFR-CT values measured at the location of the future anastomosis were significantly higher in the dysfunctional than normal grafts (0.77[0.71–0.81] vs 0.60[0.56–0.66] respectively, p = 0.0007). According to multivariable Cox regression model pre-CABG FFR-CT (HR=1.1;95%CI:1.0–1.1, p = 0.0230), and bypass graft to RCA (HR=3.7; 95%CI:1.4–9.3 vs. LAD) were independent predictors of graft dysfunction during follow-up. The optimal threshold of FFR-CT to predict graft failure was >0.68 (sensitivity 88.9% (95%CI:65.3–98.6), specificity 63.7% (95%CI:52.2–74.2), PPV 35.6% (95%CI:28.3%-43.5%), NPV 96.2% (95%CI:87.2%-99.0%). Conclusions Pre-CABG functional FFR-CT predicts future coronary bypass graft failure. This shows utility of FFR-CT for guiding coronary revascularization and also suggests significance of physiological assessment prior to CABG.