Carotid artery blood velocity decreases in patients with coronary slow flow: A manifestation of systemic arteriosclerosis

OBJECTIVES: Coronary slow flow phenomenon (CSFP) could be a manifestation of systemic arteriosclerosis, as coronary and carotid arteries have similar intimal thickening. However, as an initial cause of arteriosclerosis, hemodynamic changes in carotid arteries have rarely been studied. METHODS: Twenty patients with angiography-proven CSFP and 39 patients with normal coronary flow (NCF) were enrolled. TIMI frame counts (CTFC) were investigated. Carotid intima-media thickness (CIMT), peak systolic velocity (PSV), and end-diastolic velocity (EDV) were measured by ultrasonography, and shear rate (SR) and resistance index (RI) were calculated. RESULTS: The results showed that PSV, EDV, SR, and RI were significantly lower in patients with CSFP (p＜0.01), but CIMT was significantly increased (P ＜ 0.01). PSV, EDV, SR, and RI were negatively correlated with CTFC, while CIMT was positively correlated with CTFC. Logistic regression analysis revealed that PSV (OR = 0.95, P < 0.01) could be an independent protective factor against CSFP, but CIMT (OR = 1.10, P ＜ 0.05) and male gender (OR = 9.89, P ＜ 0.01) could be risk factors for CSFP. CONCLUSIONS: The slow flow phenomenon was observed in both coronary and carotid arteries, which could be a characteristic manifestation of systemic arteriosclerosis in CSFP; the lower wall shear stress may be the underlying mechanism. Carotid ultrasound could be applied in the noninvasive diagnosis of CSFP in the future.