Lack of correlation between coronary blood flow and carotid intima media thickness

Background: The phenomenon of slow coronary flow (SCF) in the presence of normal coronary arteries may indicate endothelial dysfunction, which is characteristic of an early stage in the development of atherosclerosis. Measurement of the Carotid Intima-Media Thickness (CIMT) allows identification of early stages of atherosclerosis. CIMT might offer a non-invasive method of diagnosing SCF patients. Previous studies demonstrated conflicting results regarding the relationship between these two phenomena. In the present study, we examined the association between coronary flow velocity and the degree of CIMT in patients with angiographically normal coronary arteries.

Methods: Coronary arterial blood flow velocity was measured using two methods - Corrected Thrombolysis in Myocardial Infarction (TIMI) Frame Count (CTFC) and Coronary Clearance Frame Count (CCFC). In addition, we measured the level of the CIMT using a special automated computerized software.

Results: Seventy Five consecutive patients were prospectively recruited. No correlation was found between CIMT and mean CTFC (r = -0.08, p = NS) or mean CCFC (r = -0.07, p = NS). In addition, CIMT values did not differ between the SCF and the Normal coronary flow (NCF) groups (0.796 mm vs. 0.805 mm, respectively, p = 0.733). Patients with SCF had higher levels of hematocrit (39.9% vs. 36.1%, p < 0.001), LDL cholesterol (101.1 mg/dl vs. 85.8 mg/dl, p = 0.01) and higher rate of current smokers (28.9% vs. 10.8%, p = 0.05).

Conclusions: Patients with angiographically normal coronary arteries and SCF do not have increased CIMT values. However, current smoking, higher LDL cholesterol and hematocrit levels are all related to slower coronary blood flow.