Objective To explore the correlation between low-density lipoprotein (LDL) level and erythrocyte rigidity index in patients with acute ischemic stroke (AIS) and its clinical significance.

Methods The clinical and biochemical data of 513 patients with AIS in the Department of Neurology, Renji Hospital Baoshan Branch Affiliated to Shanghai Jiao Tong University from January 2018 to June 2019 were retrospectively analyzed. Patients were divided into normal LDL level group and high LDL level group according to the blood LDL levels determined on admission. The clinical and biochemical characteristics between the two groups were compared. The correlation between LDL level and erythrocyte rigidity index was analyzed.

Results There was no significant difference in gender, age, previous medical history (hypertension, diabetes, coronary heart disease, atrial fibrillation), high-density lipoprotein, free fatty acid, erythrocyte aggregation index, erythrocyte deformation index, red cell distribution width, antiplatelet, hypoglycemic, and antihypertensive drugs between the normal LDL group and high LDL group. There were significant differences in erythrocyte rigidity index, RBC hematocrit, mean corpuscular volume (MCV), total cholesterol, triglyceride, LDL, apolipoprotein A1, apolipoprotein B, apolipoprotein E, expanded disability status scale (EDSS) score and lipid-lowering drugs between the two groups (P < 0.05). There was a positive correlation between LDL level and erythrocyte rigidity index in patients with AIS (r=0.121, 95% confidence interval 0.035-0.206, P=0.006).

Conclusions Increased LDL level is associated with increased erythrocyte stiffness in patients with AIS, which indicates that AIS might be caused by LDL through affecting erythrocyte deformability.