Objective: This study aims to find the relationship between whole blood viscosity (WBV) and amputation events occurring within 1 year of patients with lower extremity peripheral arterial (LEPAD) disease who cannot be revascularized by surgical or percutaneous methods.

Materials and Methods: The study retrospectively examined the data of 261 LEPAD patients with critical limb ischemia. WBV values of the patients were found with a formulation obtained from the total protein and hematocrit values in the blood samples (Simone’s formula).

Results: Amputation developed in 51 (19.6%) patients. Hemoglobin, hematocrit, white blood cell count, neutrophil, platelet, WBV at high shear rate (HSR) (16.58±2.13 vs. 15.74±1.47, p<0.001) and WBV at low shear rate (LSR) of patients with amputation (100.15±14.97 vs. 92.84±13.39, p=0.002) value was found to be higher. As a result of multivariate regression analysis, WBV at HSR (OR: 1.096 95%CI (1.067-1.182), p=0.002) and WBV at LSR (OR: 6.481 95%CI (4.102-9.486), p<0.001) were found to be independent risk factors indicating the development of amputation. As a result of the receiver operating characteristics curve analysis, the cut-off value showing amputation for WBV at HSR is 16.34 (69% sensitivity, 68.6% specificity, and area under the curve (AUC): 0.728(0.532-0.823), p=0.005), a cut-off value indicating amputation for WBV at LSR is 97.48 (71.5%) sensitivity, specificity of 70.2% and AUC: 0.736(0.551-0.842), p=0.003).

Conclusions: According to the shear rate, both WBV values were found predictive of amputation in patients with critical limb ischemia who could not be revascularized.