Assessment of whole BLOOD viscosity in predicting stent restenosis in patients with coronary artery disease

Background: Coronary artery disease (CAD) is one of the leading causes of death in the world. There have been many developments in the diagnosis and treatment of CAD in recent years. Percutaneous coronary intervention (PCI) is a commonly used revascularization method in the treatment of CAD. With the increasing use of PCI, in-stent restenosis (ISR) has become a more important and common problem. Whole blood viscosity (WBV) plays a role as an important predictor of cardiovascular diseases. In this study, we planned to investigate the role of WBV in the development of ISR, considering the relationship between endothelial inflammation and WBV. Method: Patients who underwent coronary angiography (CAG) with a prediagnosis of chronic coronary syndrome at Ankara City Hospital between March 2019 and June 2022 were included in the study. 342 patients with ISR who suitable for the including criteria were included in the restenosis group (cases), and 460 patients who did not suitable these criteria were included in the control group. Demographic data of the patients included in the study, angiography images of the first implanted stent were scanned retrospectively using patient files, medical records, and e-nabiz system. WBV was calculated with HCT (%) and plasma protein concentration (g/L) with the validated formulas of Simone et al for both LSR (low shear rate 0.5 s-1) and HSR (high shear rate 208 s-1). ROC curve analysis was performed to predict ISR and to determine predictive values of HSR and LSR levels. Additionally, the cumulative risk ratios were calculated by the Kaplan-Meier method and groups with low and high WBV were compared for both HSR and LSR using the log-rank test. Also, multivariate Cox regression analyzes were performed in two separate models to evaluate whether HSR and LSR were independent predictors of restenosis. Results: The mean age of the study population was 63±10 years and 75% (n=599) of the patients were male. Diabetes was detected in 339 (42%), hypertension in 567 (72%), and dyslipidemia in 231 (29%) of the patients. HSR (16.8±1.0 vs. 15.6±0.9 cP, p<0.001) and LSR (83.1±8.4 vs. 80.8±8.0 cP, p<0.001) levels were higher in the group with ISR compared to the group without restenosis. In ROC analysis, the cut-off value for LSR was 40.04 cP with 80% sensitivity and 76% specificity (AUC 0.84; 95% CI, 0.81-0.87; p < 0.001), cut-off value for HSR 16.21 cP with 78% sensitivity and 75% specificity. (AUC 0.82; 95% CI, 0.79-0.85; p < 0.001) predicts ISR. In Kaplan-Meier analysis; high WBV calculated by HSR and LSR had a higher cumulative risk for ISR than for low WBV (Log-rank test, P <0.001). In multivariate Cox regression models; HSR (HR: 1.48, 95% CI: 1.33-1.65, p<0.001) and LSR (HR: 1.02, 95% CI: 1.01-1.03, p<0.001) were determined as independent predictors of ISR. In addition, smoking, type of first stent implanted, stent length and diameter were found to be independent predictors for ISR in Cox regression analysis. Conclusion: In our study, we found that WBV calculated with both LSR and HSR was an independent predictor of the development of ISR. In addition, increased WBV may play a role in the development of neointimal hyperplasia and ISR as a result of the endothelial inflammation it causes. This situation may inspire new studies on the pathogenesis of ISR. While this may inspire new studies on the pathogenesis of ISR, WBV measurement can be applied in routine practice as a parameter to predict the occurrence of ISR before CAG. Keywords: Chronic coronary syndrome, whole blood viscosity, in-stent restenosis