Nap, Alexander

Abstract Background Coronary computed tomography angiography (CCTA) and myocardial perfusion imaging (MPI) are guideline-recommended to assist in clinical decision-making in patients with prior coronary artery bypass grafting (CABG). However, the value of combining CCTA and MPI for guiding revascularization decision-making in post-CABG patients with recurrent ischemic symptoms remains unexplored. In this study, we compared Heart Team strategies for revascularization based on CCTA and MPI as standalone and hybrid CCTA/MPI imaging, to strategies guided by invasive coronary angiography (ICA). Methods We included symptomatic patients with prior CABG who underwent CCTA and MPI (single-photon emission computed tomography, positron emission tomography or stress perfusion cardiac magnetic resonance imaging) preceding ICA. Simulated Heart Teams, blinded to other Heart teams and outcomes, performed revascularization decision-making based on conventional CCTA, MPI and a hybrid CCTA/MPI strategy (non-invasive Heart Team) or based on ICA (invasive Heart Team). The primary outcome was the Cohen’s kappa agreement (κ) between non-invasive and invasive Heart Teams. Results A total of 115 patients (mean age 73±7 years; 99 [86%] male) were included. Revascularization was recommended in 96 patients (83.5%) by CCTA, 92 patients (80.0%) by MPI, 80 patients (69.6%) by hybrid CCTA/MPI and 76 patients (66.1%) by ICA. The agreements were significant but low for CCTA (κ: 0.25 [95% confidence interval (CI): 0.07-0.42], P=0.003) and MPI (κ: 0.27 [95% CI: 0.09-0.48], P=0.002) compared to ICA, with only a modest increase when using the hybrid non-invasive imaging strategy (κ: 0.32 [95% CI: 0.14-0.51], P<0.001). Conclusions In patients with recurrent ischemic symptoms after CABG, Heart Team assessment of conventional CCTA and MPI yielded similarly poor agreements with revascularization strategies based on ICA, with only a modest improvement observed when using a hybrid CCTA/MPI approach. Overall, non-invasive imaging alone appears insufficient to accurately guide treatment strategies in patients with prior CABG, and their use as gatekeeping for ICA in these patients should be questioned.

ABSTRACT Background The relationship between height differences related to graft anatomy and physiological pressure indices in coronary bypass grafts has not been studied. We sought to study the impact of hydrostatic pressure on fractional flow reserve (FFR) in saphenous vein grafts (SVGs). Methods Included were 66 symptomatic patients (76 SVGs) with prior coronary artery bypass grafting who underwent coronary computed tomography angiography (CCTA) preceding invasive coronary angiography with FFR interrogation of ≥ 1 SVGs. The graft course and height excursion were reconstructed based on CCTA images. The impact of hydrostatic pressure on FFR (corrected FFR) was calculated by adding or subtracting 0.077 mmHg to the distal coronary pressure for every millimeter height difference in a supine position between the SVG ostium and the pressure wire tip position. Results The height difference (mm) between the SVG ostium and pressure wire tip position was largest for single SVGs to the circumflex artery (Cx; −55.1 ± 17.0), followed by sequential SVGs to the Cx (−51.8 ± 17.3) and the right coronary artery (RCA; −36.7 ± 21.6). The correlation between height difference and uncorrected FFR was −0.59 ( p < 0.001). Corrected FFR was lower as compared to uncorrected FFR in the overall cohort (0.86 ± 0.17 vs. 0.88 ± 0.18), in single SVGs to Cx (0.85 ± 0.17 vs. 0.90 ± 0.18), and in sequential SVGs to Cx (0.92 ± 0.14 vs. 0.96 ± 0.15) and RCA (0.82 ± 0.17 vs. 0.85 ± 0.21) ( p < 0.001 for all). Conclusions Hydrostatic pressure related to height differences along the course anatomy of SVGs can impact FFR measurements, with corrected FFR being significantly lower in SVGs to the Cx and sequential SVGs to the RCA.