Computerized Axial Tomographic (CAT) Diagnosis Of Vascular Thrombosis And Patency Of Aorto-Coronary Bypass Graft

During the past decade, aorto-coronary bypass surgery (ACBS) has been widely prescribed as treatment of angina pectoris. Dysfunction or closure of an aortocoronary bypass graft (ACBG) is generally suggested by a number of vague subjective complaints and few, if any, objective signs derived by history, physical examination, resting and stress E.K.G., and lately by Thallium201 regional myocardial perfusion studies. Definitive confirmation of graft closure or stenosis has traditionally required post operative selective catheterization and angiography of the grafts in question. We have utilized CAT to determine patency of an ACBG with encouraging results. Biological motion has been the principle deterrent to the use of CAT in evaluating the coronary arteries and cardiac chambers. Third and fourth generation scanners have been employed to explore the feasibility and potential use of CAT in imaging cardiac structures. Surprisingly, excellent quality images are currently being obtained with exposure times of one to five seconds, even though some of these images are reconstructed from repetitive data obtained during one or more cardiac cycles partially degrading the image. CAT demonstration of the cross-sectional anatomy combined with simultaneous contrast media enhancement represents the basic ingredients utilized to demonstrate the patency of ACBG. Sixty-five patients have undergone this procedure after single or multiple revascularization procedures. Eighteen of these patients, with a total of thirty-three grafts, had correlative selective angiography of the individual venous grafts. Twenty-two grafts proved to be patent with both techniques while ten of eleven thrombosed grafts were properly predicted by CAT. The benefits of this relatively non-invasice, safe, repeatable, and accurate method for detectinq ACBG is presented.