The detection of pulmonary embolisms after a coronary artery bypass graft surgery by the use of 64-slice multidetector CT

The purpose of this study was to examine the incidence of pulmonary embolism (PE) after a coronary artery bypass graft (CABG) using 64-slice multidetector CT (MDCT), and to determine the correlations between the occurrence of a PE and the clinical or surgical parameters. Three hundred and twenty-six consecutive patients, who underwent coronary CT angiography using 64-slice MDCT to assess the graft patency after CABG, were enrolled in this study. Additional axial CT images, which were reconstructed by adopting a large field of view and thinner image slices, were reviewed for the presence of PE. The relationship between the occurrence of a PE and the type of surgery (off-pump CABG versus conventional CABG), number of target vessels, use of a saphenous vein graft, and length of stay in the intensive care unit (ICU) were evaluated. PE was detected on the CT images of 33 patients (10.1%), which involved the lobar or more proximal arteries in seven patients and the segmental or subsegmental arteries in 26. PE occurred more frequently after off-pump CABG (16.5%, 14/85) than after conventional CABG (7.9%, 19/241) (P = 0.024). Patients with PE were older (67 years vs. 62.7 years) and had longer stays in the ICU (5.6 days vs. 3.8 days) than those without (P = 0.013 and P = 0.007, respectively). No significant difference was observed in the number of target vessels and use of a saphenous vein graft between patients with and without an embolism. In a multi-variable analysis, the age of the patient, surgical methods, and ICU stay were independent predictors for the occurrence of PE (P = 0.013, P = 0.017, and P = 0.005, respectively). MDCT helps detect PE in patients after CABG. It is encountered more frequently after off-pump CABG than after conventional CABG and in older patients with longer ICU stays.