The Relationship between Blood Viscosity and Isolated Coronary Artery Ectasia.

Background: It is unclear whether isolated coronary artery ectasia (iCAE) is associated with whole blood viscosity (WBV). In the present study, we investigated WBV in coronary artery ectasia (CAE) patients.

Methods: Seventy-eight patients with iCAE and 83 controls with normal coronary arteries were selected from 12290 patients who underwent coronary angiography between January 2014 and December 2017. WBV was calculated with a validated equation from hematocrit and total plasma protein levels for a low (LSR) and high (HSR) shear rate.

Results: Baseline demographic characteristics and medical history of the groups were similar. The mean level of C-reactive protein (2.1 ± 0.53 vs. 1.93 ± 0.44; p = 0.042) and total protein (7.2 ± 0.3 vs. 7.0 ± 0.6; p = 0.009) were significantly higher in the iCAE group than in the control subjects. Both HSR (4.57 ± 0.6 vs. 3.9 ± 0.7; p < 0.001) and LSR (33.5 ± 9.6 vs. 25.1 ± 9.2; p < 0.001) levels were significantly higher in the iCAE group than in the control group. In ROC analysis, a cut-off value of 4.19 WBV for HSR had an 80.8% sensitivity and 72.3% specificity [area under the curve (AUC): 0.779, 95% CI 70.6-85.1; p < 0.001] and a cut-off value of 27.5 WBV for LSR had an 80.1% sensitivity and 72.3% specificity for predicting iCAE (AUC: 0.788, 95% CI 71.4-86.2; p < 0.001). In multivariate analysis, both LSR (p < 0.001, OR 1.10, 95% CI 1.05-1.15) and HSR (p < 0.001, OR 4.60, 95% CI 2.33-9.09) were independent predictors for the presence of iCAE.

Conclusions: In the present study, we determined that in WBV, both HSR and LSR were significantly higher in the iCAE group than in the control subjects, and that this may be a possible cause of iCAE.