Alterations of Venous Flow in Hemiparetic Patients

Abstract

Unilateral extremity edema and an increased incidence of venous thrombo sis are known to occur in association with hemiparesis. This phenomenon has been ascribed to either loss of muscle pump function, resulting in venous flow stasis, or to alterations in vasomotor tone secondary to the central cerebral le sion. Thirty-five patients with hemiparesis due to stroke were studied with duplex scanning to determine the nature of changes in venous flow. Patients with pre- existing arterial or venous disease were excluded. Femoral and popliteal vein size and peak venous flow velocity were quantitated in the paretic and the unaffect ed limb. Muscle strength and recovery (Brunnstrom staging) were independent ly assessed and compared with venous measurements. The relative change in vein size was found to be significantly increased at both locations in the femoral (p = .007) and popliteal (p = .019) locations in the paretic as compared to the normal limb. Concurrently, the peak flow velocity was significantly reduced in the popliteal vein (p < 0.05), while only mildly reduced in femoral vein. A mild inverse relationship was apparent between muscle strength and femoral venous size, but otherwise, there appeared to be no significant as sociation between muscle strength and measured venous parameters. These results indicate a reduction in flow velocity and an increase in venous size occurring with hemiparesis. Because these changes do not significantly correlate with muscle strength, it is felt that they are most likely due to alterations of vasomotor func tion rather than of the muscle pump mechanism. Changes of this nature can lead to venous thrombosis.