SYNTAX Score in Patients with High Computed Tomography Coronary Calcium Score

To study the conventional coronary angiogram ( CA) findings in patients with high coronary calcium on multidetector computed tomogram.

Fifty patients with coronary calcium high enough in its extent and location to interfere with the interpretation of a contrast-filled coronary artery for a significant lesion were studied with conventional CA. Framingham risk score (FRS), computed tomography (CT) coronary calcium score (CCS), and SYNTAX score (SS) from the CA were calculated by separate investigators who were blinded to other scores. Effectively, 250 coronary arteries (left main, left anterior descending, left circumflex, and right coronary artery and posterior descending artery in each subject) with calcium scores were studied for lesions on CA.

Thirty-five subjects had high FRS, 10 had intermediate FRS, and 5 had low FRS. Eight subjects of 25 (32%) with CCS between 350 and 1000 had no significant coronary artery disease (CAD). Overall, the CCS and the SS had a strong agreement with each other (r = 0.68, P < 0.01) that persisted in those with very high scores >1000 (r = 0.55, P < 0.01, n = 30), but only a nonsignificant weak correlation with scores between 350 and 1000 (r = 0.1, P = 0.62, n = 20). Individual vessel calcium scores correlated strongly for the presence of any lesion (r = 0.52, P < 0.01) in the same artery but only weakly for a significant lesion (r = 0.29, P = 0.05).

High CT CCS in this cohort of intermediate to high (Framingham score) risk patients correlated strongly with the subject's global burden of the CAD as derived by the SS, more so for subjects with very high scores. Similarly, CCS correlated strongly with the presence of any lesion but only weakly for a significant stenosis; also, about one-third of patients with CCS between 350 and 1000 may not have significant disease on conventional CA.