The Association between Whole Blood Viscosity and Coronary Collateral Circulation in Patients with Chronic Total Occlusion

BACKGROUND AND OBJECTIVES: Coronary collateral circulation (CCC) has been attributed as inborn bypass mechanisms supporting ischemic myocardium. Various factors have been postulated in CCC. Whole blood viscosity (WBV) has been an underappreciated entity despite close relationships between multiple cardiovascular diseases. WBV can be calculated with a validated equation from hematocrit and total plasma protein levels for a low and high shear rate. On the grounds, we aimed to evaluate the association between WBV and CCC in patients with chronic total occlusion. SUBJECTS AND METHODS: A total of 371 patients diagnosed as having at least one major, chronic total occluded coronary artery were included. 197 patients with good CCC (Rentrop 2 and 3) composed the patient group. The poor collateral group consisted of 174 patients (Rentrop grade 0 and 1). RESULTS: Patients with poor CCC had higher WBV values for a low-shear rate (LSR) (69.5±8.7 vs. 60.1±9.8, p<0.001) and high-shear rate (HSR) (17.0±2.0 vs. 16.4±1.8, p<0.001) than the good collateral group. Correlation analysis demonstrated a significant negative correlation between the grade of CCC and WBV for LSR (β=0.597, p<0.001) and HSR (β=0.494, p<0.001). WBV for LSR (β=0.476, p<0.001) and HSR (β=0.407, p<0.001) had a significant correlation with the synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) score. A multivariate analysis showed that the WBV for both shear rates were independent risk factors of poor CCC (WBV at LSR, OR: 1.362 CI 95%: 1.095-1.741 p<0.001 and WBV at HSR, 1.251 CI 95%: 1.180-1.347 p<0.001). CONCLUSION: WBV has been demonstrated as the overlooked predictor of poor coronary collateralization. WBV seemed to be associated with microvascular perfusion and angiogenesis process impairing CCC development.

forgotten variable of shear stress in mitral annular calcification: whole blood viscosity

The aim of this research was to assess the relationship between mitral annular calcification [MAC] and whole blood viscosity [WBV]. A total of 184 patients with MAC and 133 patients without MAC were enrolled in the study. The WBV was calculated with a confirmed formulation using the hematocrit and total plasma protein at a low shear rate [LSR] and high shear rate [HSR]. Early diastolic mitral annular velocity [Ea] and late diastolic mitral annular velocity [Aa] were measured using pulse Doppler tissue echocardiography. Pearson's correlation analysis was performed to assess the relationship between WBV and mitral annular motion velocities. The effects of different variables on the occurrence of MAC were assessed in univar-iate and multivariate logistic regression analysis. In patients with MAC, WBV values were significantly higher at HSR [18.04 +/- 0.84 vs. 17.25 +/- 0.96 208 s[-1], p < 0.001] and at LSR [78.0 +/- 14.2 vs. 61.9 +/- 17.1 0.5 s[-1], p < 0.001]. The WBV atHSR and LSR were significantly correlated with Ea[r = -0.477, p < 0.001; r = -0.385, p < 0.001, respectively] and Aa[r = -0.544, p < 0.001; r = -0.323, p < 0.001, respectively]. Multivariate analysis showed that WBV of both shear rates was an independent predictor of MAC. Using the ROC curve, a cut-off value of 70.1 for WBV at LSR had a sensitivity of 83.7% and a specificity of 73.7% [AUC 0.785, p < 0.001] and a WBV cut-off value of 17.5 at HSR had a sensitivity of 79.6% and a specificity of 71.4% [AUC 0.761, p < 0.001] for the prediction of MAC Patients with MAC had significantly higher WBV, which independently predicted the presence of MAC. WBV had an inverse correlation with mitral annular motion velocities, indicating that a higher WBV may lead to greater limitation in annular motion and, thus, more calcification