Vascular Function is Preserved in the Paretic Limb Following a Stroke

Abstract

It is well accepted that physical activity improves peripheral vascular function. Thus, vascular dysfunction may occur in the paralyzed or partially paralyzed limb following a stroke due to chronic limb specific physical inactivity. Currently there is a dearth of information that describes the consequence of chronic motor deficits on vascular function following a stroke. PURPOSE: The purpose of this investigation was to determine if paralysis of a limb following a stroke resulted in vascular dysfunction within that limb. METHODS: Eight relatively healthy individuals (3 females, 5 males, 54±9 years of age) with stroke induced paralysis in one arm (>1 year) were recruited for this investigation. Limb specific physical activity was monitored with Actigraph accelerometers worn on each wrist for 3 days. Pulse wave velocity (PWV) and flow mediated dilation (FMD) were also determined for both the control and paralyzed arm. RESULTS: As expected physical activity of the paretic arm (530±290 average counts per minute) was drastically reduced compared to control arm (2176±578 average counts per minute)(P0.57). During the first 20 seconds following the cuff release from the 5 minute occlusion the hyperemic response was at least 30% smaller in the paretic arm compared to the control arm (P<0.03). CONCLUSION: This data indicates that limb specific physical inactivity following a stroke does not result in limb specific vascular dysfunction. In general, the variation within these variables was much greater in the paretic limb compared to control limb. Blood flow response following a 5 minute occlusion was much greater in the control arm. This may be due to variation in limb size, metabolic differences, capillary density differences and/or arterial size. It is possible that this may be due to the variation in rigor/flaccidity in the paretic arm. Additional investigations will allow for the partitioning of those with spastic or flaccid paralysis.