Detection of vein graft disease using 4-row computed tomography. Evaluation of coronary bypass graft patency and correlation with the Ca-score.
BACKGROUND
Multi-row computed tomography (MDCT) is a promising non-invasive technique and capable of rapid imaging of cardiac structures, including coronary arteries and bypass grafts during a single held breath. In this study, we evaluated coronary artery bypass graft (CABG) patency by comparing 4-slice computed tomography with conventional contrast angiography. One disadvantage of MDCT is the limited diagnostic accuracy with + increased calcification of the grafts. Therefore, the correlation between Ca-grading and diagnostic accuracy was examined.


METHODS
We examined 30 patients with 104 bypass grafts with a 4-row MDCT scanner. On the basis of the Ca-score, patients were divided into 3 groups.


RESULTS
It was possible to assess the exact degree of stenosis in 25 of 32 > 50% stenoses with 4-row MDCT, 7 stenoses were underestimated. All occlusions in 21 patients were identified correctly, 33 graft segments were underestimated in MDCT, of which 28 were in the group with a Ca-score of > 800.


CONCLUSIONS
MDCT allows non-invasive angiographic evaluation of coronary bypass grafts with a high diagnostic accuracy. However, the method strongly depends on the degree of vascular calcification and underrates the degree of stenosis subject to the Ca-score. This is a distinct limitation in distal vascular segments of small calibre which cannot be validly displayed. In patients with low or moderate Ca-score values, MDCT coronary angiography is promising new technique with a high diagnostic accuracy for the detection of graft stenosis or occlusions.
Department of Thoracic and Cardiovascular Surgery, University Hospital, Frankfurt/Main, Germany. thomaswittlinger@t-online.de
T
T
Wittlinger
I
I
Martinovic
F
F
Bakhtiary
F
F
Oezaslan
A
A
Moritz
K
K
Ehrhard
D000368:Aged; D002114:Calcinosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods*; D023903:Coronary Restenosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011475:Prosthesis Failure; D012501:Saphenous Vein / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000637:transplantation; D014057:Tomography, X-Ray Computed; D014654:Vascular Patency / Q000502:physiology*