Abstract 3273: Detection of Significant Coronary Stenosis by 64-Slice Computed Tomography Angiography in Heart Transplant Recipients - A Comparative Study with Conventional Angiography
Cardiac allograft vasculopathy (CAV) still remains the major limiting factor of long-term positive outcome after heart transplantation. The current gold standard for detecting CAV is conventional coronary angiography (CCA). Multislice-Computertomography-Angiography (MSCTA) has recently proven effective in detecting coronary stenosis in non-transplanted patients. Therefore we sought to prove its ability to evaluate luminal obstruction due to CVA as a non-invasive alternative to CCA. 34 consecutive male heart transplant recipients underwent 64-slice-MSCTA (Sensation 64, Siemens Medical Solutions, Forchheim, Germany) within 24 h after annual routine CCA. To obtain a resting heart rate <70 bpm all patients received oral beta-blockers (100mg metoprolol) 1 h before the scan. Significant stenosis was defined as luminal obstruction >50% in quantitative coronary analysis (QCA). 26/34 (76%) patients were included for further analysis (all vessels, AHA 15 segment model). Due to renal insufficiency 4 patients did not undergo MSCTA and 4 studies had to be excluded due to inadequate image quality (motion artifacts, heart rate = 86±7 bpm). Despite high heart rates (82±14 bpm) diagnostic image quality was achieved in the remaining 26/30 (87%) patients and a comparison of 375/390 segments (96%) between MSCT and QCA was possible. Consensus in classifying the degree of stenosis with both methods was achieved in 7/8 angiographically stenotic or totally occluded segments and in 352/367 of disease free segments. 15 segments without evidence of atherosclerosis on QCA were graded stenotic on CT and in two segments the stenosis was overestimated. Sensitivity and specificity for the detection of significant stenosis was 88%, and 96% respectively (negative predictive value = 99%). The diagnostic accuracy was calculated as 96%. On a per patient basis 64-slice MSCT correctly ruled out significant CAV in 20/22 (90%) patients compared to conventional angiography. 64-slice-MSCT therefore is a reliable non-invasive diagnostic tool for detecting significant stenosis of coronary arteries in heart transplantation recipients and may be considered as a noninvasive alternative to CCA. Despite higher heart rates diagnostic image quality could be achieved in most studies.