Clinical and laboratory correlates of whole blood viscosity in patients with ischemic heart disease - a large-scale, single-center cohort study

Abstract Background Whole blood viscosity (WBV) is the dynamic resistance toward the vessel under varying shear rates, may serve as a hemorheologic biomarker in patients at risk of vascular thrombosis. Although WBV is known to be associated with hematocrit, its relationship with other clinical and laboratory variables in ischemic heart disease (IHD) remains underexplored. This study aimed to investigate WBV and its correlates in a large, single-center IHD cohort. Methods The Kangnam Sacred Heart Hospital–Whole Blood Viscosity (KSH-WBV) registry is a prospective, all-comer, single-center cohort designed to evaluate the role of WBV in various cardiovascular conditions. For this analysis, we included only patients with IHD, further classified as acute myocardial infarction (AMI), unstable angina (UA), stable angina (SA), and variant angina (VA). WBV was measured using the Rheovis-200 plasma viscometer (Biorheologics, Korea) via a fully automated scanning capillary method, at both low (1/s, diastolic WBV) and high (300/s, systolic WBV) shear rates. Baseline clinical and laboratory characteristics were analyzed across the subgroups. Results From July 1, 2023, to April 31, 2025, a total of 683 IHD patients (AMI: 184; UA: 32; SA: 445; VA: 22) with WBV data at initial presentation were enrolled. Mean age was 64.6 ± 11.5 years; 66.6% were male. The prevalence of current smoking was highest in AMI (26.6%), followed by UA (12.5%), SA (12.6%), and VA (9.1%) (p < 0.05). Rates of hypertension, diabetes, and dyslipidemia were similar among groups. Laboratory profiles were generally comparable, though AMI patients had higher CRP and AST levels. Ticagrelor use was significantly more common in AMI (23.8%) versus UA (9.4%), SA (0.7%), and VA (0%) (p < 0.001). Both systolic and diastolic WBV values were significantly higher in the AMI and UA groups compared with SA and VA (Figures 1A and 1B). Diastolic WBV was notably elevated in males, current smokers, and patients without chronic kidney disease (CKD) (29.90 ± 8.16 vs. 24.42 ± 6.87, p < 0.001; 32.47 ± 9.24 vs. 30.11 ± 8.43 vs. 27.05 ± 7.58, p < 0.001; and 28.38 ± 8.10 vs. 23.84 ± 8.42, p = 0.002, respectively). Diastolic WBV positively correlated with age, weight, hematocrit, BUN, total cholesterol, triglycerides, LDL cholesterol, and fasting glucose (Figure 2). Conclusion WBV significantly varied among different types of ischemic heart disease and was associated with multiple clinical and laboratory parameters. These findings support the potential role of WBV as a novel biomarker in IHD. Further studies are warranted to evaluate its prognostic implications.For image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.