Left ventricular ejection fraction impact on contrast opacification of coronary artery bypass grafts in 64-slice multidetector computed tomography angiography

The objective of the study was to find whether changes in left ventricular ejection fraction (LVEF) have an impact on contrast opacification of coronary artery bypass grafts (CABGs) in coronary computed tomography angiography (CTA).

One hundred two CABG patients were assessed using 64-slice CTA. Concurrently, their LVEF was measured using computed tomography. Density of grafts were measured, and their correlation with parameters including LVEF determined.

A total of 253 grafts including 89 left internal mammary artery (LIMA) grafts, 41 saphenous vein grafts (SVGs) to diagonal artery, 66 SVGs to obtuse marginal (OM) artery, and 57 SVGs to posterior descending artery (PDA) were patent and assessed. Mean measured LVEF was 49% (SD, 7%). Mean attenuation value of the LIMA grafts was 302.39 (SD, 91.16) Hounsfield units (HU), and those of SVGs to diagonal artery, SVGs to OM artery, and SVGs to PDA were 348.73 (SD, 100.38) HU, 326.95 (SD, 101.41) HU, and 339.50 (SD, 111.67) HU, respectively. A significant negative correlation was found between LVEF and mean attenuation values of LIMA graft (P < 0.001; r = -0.80), SVG to diagonal artery (P < 0.001; r = -0.66), SVG to OM artery (P < 0.001; r = -0.75), and SVG to PDA (P < 0.001; r = -0.76).

A negative correlation was found between density of grafts and LVEF of CABG patients, which is usually echocardiographically assessed before CTA.