Diagnostic accuracy of Doppler ultrasonography for assessment of internal thoracic artery graft patency

Abstract

The main purpose of this study was to assess the patency of left internal thoracic artery (LITA) graft by using color Doppler ultrasonography (CDUSG) and furthermore to determine the sensitivity and specificity of CDUSG for patency by using coronary angiography as the reference standard. This study is an observational cohort study on diagnostic accuracy that was held between August 2008 and October 2009. CDUSG was performed in 138 consecutive patients who had angina symptom or positive ischemic findings following coronary artery bypass surgery. LITA blood flow velocity at peak-systole (PSV), diastole (PDV) and end-diastole (EDV) was recorded. All patients were also assessed by coronary angiography for LITA graft patency. Statistical analysis was performed by using independent samples t-test, Mann-Whitney U test, chi-square test and receiver operating curve analyses (ROC). Seventy-eight of all patients had functional LITA grafts and 59 patients had dysfunctional LITA grafts according to CDUSG-derived parameters, whereas we cannot conclude about one patient's LITA graft functionality. The LITA grafts were visualized angiographically in all cases. Of all 138 patients, 60 patients had dysfunctional LITA grafts after angiographic evaluation. The ROC analyses showed that PDV (AUC=0.899, 95% CI 0.844 to 0.953; p<0.001) and EDV (AUC=0.900; 95% CI 0.847 to 0.953; p<0.001) values were also strongly associated with graft functionality. We found out that CDUSG predicts LITA graft functionality with a sensitivity and specificity of 100% and 98.4% respectively. The accuracy of the CDUSG was calculated as 99.3%. CDUSG is a reliable non-invasive method for assessment of LITA graft patency.