Fibrinogen and Viscosity as Risk Factors for Subsequent Cardiovascular Events in Stroke Survivors

Abstract

▪ Objective: To investigate whether abnormalities in blood viscosity predict a poor prognosis for subsequent cardiovascular events in stroke survivors.

▪ Design: Nested case-control study among a cohort of survivors of a first stroke, followed for an average of 2 years. Patients with a second stroke, myocardial infarction, or cardiovascular death were matched with patients who did not have such events (control patients).

▪ Setting: Buchberg-Klinik, Bad Tölz, Germany, a specialized center for stroke rehabilitation.

▪ Patients: A total of 625 consecutive patients. Twenty-one patients (3.5%) were lost to follow-up. Sixty pairs were matched.

▪ Measurements: Native and hematocrit-standardized blood viscosity at three shear rates, hematocrit, plasma viscosity, fibrinogen, erythrocyte sedimentation rate, total leukocyte count, and the matching variables.

▪ Results: Eighty-five patients had a second stroke, myocardial infarction, or died due to a cardiovascular event. Patients with re-events had higher blood viscosity and fibrinogen levels than the control patients. In the 60 matched pairs, the mean of the paired differences between patients with re-events and control patients was 5.03 mPa · s (95% Cl, 1.262 to 8.941; P = 0.01) for native blood viscosity at shear rate 0.7 s^-1, for plasma viscosity, 0.044 mPa · s (Cl, 0.006 to 0.083; P > 0.02), and for fibrinogen, 0.056 g/L (Cl, 0.010 to 0.101; P > 0.02). Odds ratios were significantly increased only for plasma viscosity (odds ratio, 2.86; Cl, 1.06 to 8.43) and fibrinogen (odds ratio, 3.67; Cl, 1.31 to 11.69).

▪ Conclusions: Hyperfibrinogenemia is an independent risk factor for cardiovascular events in stroke survivors. Intervention trials with fibrinogen lowering measures may be warranted.