Elevated coronary whole blood viscosity in acute coronary syndrome patients

OBJECTIVES: As most clinical studies measure whole blood viscosity (WBV) from peripheral samples, potential differences in WBV obtained from the coronary arteries are often ignored. This study investigated differences in WBV measured from coronary artery specimens in patients with and without acute coronary syndrome (ACS). METHODS AND RESULTS: Consecutive patients with chest pain who underwent diagnostic coronary angiography were divided into two groups [non-ACS (n = 16), ACS (n = 22)]. The ACS group consisted of unstable angina (n = 13) and acute myocardial infarction (n = 9) patients. Two blood samples were obtained from each patient at the both coronary artery ostia prior to coronary angiography. Low-shear and high-shear blood viscosities (BVs) were measured at shear rates of 1 and 300 s^-1, respectively, by a scanning capillary tube viscometer (Bio-Visco Inc., SouthKorea). Both low-shear and high-shear BVs obtained from peripheral, left and right coronary arteries were not different in both groups. Mean coronary low-shear WBV values obtained in ACS group were 29.2% higher than those in non-ACS group (295.3 ± 87.2 mP vs. 228.5 ± 69.2 mP, p = 0.016). Mean coronary high-shear WBV values obtained in ACS group were 15.6% higher than those in non-ACS group (42.9 ± 10.0 mP vs. 37.1 ± 4.6 mP, p = 0.036). CONCLUSIONS: Direct measurement of WBV from the coronary artery showed no differences with peripheral samples. Future larger studies are needed to clarify our results.