It is now accepted that carotid artery stenosis should be treated as a part of systemic atherothrombosis. However, little is known about the association in atherosclerosis between the carotid and coronary arteries. We retrospectively investigated the association between carotid plaque vulnerability diagnosed on carotid magnetic resonance imaging (MRI) and coexisting coronary artery stenosis in patients scheduled for carotid endarterectomy (CEA) or carotid artery stenting (CAS).
Eighty-nine consecutive cases that underwent carotid reconstruction for carotid artery stenosis at Kyoto University Hospital between 2010 and 2015 were enrolled in this study. Ten cases that received neither coronary angiography (CAG) nor coronary computed tomography angiography (CCTA) as preoperative examinations, 6 cases with restenosis after CEA or CAS, and 2 cases that did not undergo carotid MRI were excluded. We evaluated relative overall signal intensity (roSI) of the carotid plaque on T1-weighted imaging and coronary artery stenosis detected on CAG or CCTA in the remaining 71 cases. Carotid plaques with roSI >1.5 were defined as MRI-detected vulnerable plaques.
Thirty-one cases had a history of previous coronary intervention (stenting or bypass surgery), of which 26 (84%) showed carotid vulnerable plaques. In the cases with no history of coronary intervention, coronary artery stenosis was newly detected in 21 cases, and was not demonstrated in the other 19 cases. Fifteen of the 21 cases with coronary artery stenosis (71%) also showed carotid vulnerable plaques. On the other hand, only 4 of the 19 cases without coronary artery stenosis (21%) had carotid vulnerable plaques, representing a significant difference (P<0.05).
Among the cases with no history of coronary intervention, prevalence of coronary artery stenosis in cases with carotid vulnerable plaques was 79%, significantly higher than that in cases without carotid vulnerable plaques (29%).
In conclusion, this study demonstrated that patients with carotid vulnerable plaques are more likely to have advanced coronary artery stenosis. Plaque characterization by carotid MRI is useful not only for treatment of carotid artery stenosis, but also for predicting coronary artery stenosis.