Autonomic dysfunction in different subtypes of post-acute ischemic stroke

Abstract

Objectives: Central autonomic impairment is frequent in ischemic stroke at acute or chronic stages. The mechanism by which these symptoms occur in patients with ischemic stroke has not been elucidated. This study sought to investigate cardiovascular autonomic function in patients with different subtypes of post-acute ischemic stroke.

Methods: 77 ischemic stroke patients [50 patients with large-artery atherosclerosis (LAA) and 27 patients with small-vessel occlusion (SVO), average 6 months after stroke onset] and 37 elderly controls were recruited. All performed Ewing's battery autonomic function tests and power spectral analysis of heart rate variability (HRV).

Results: Stroke patients with both LAA and SVO had significantly lower low frequency power spectral density than controls. The prevalence of autonomic dysfunction in both groups (82.0% patients with LAA and 63.0% with SVO) was higher than that in controls (21.6%). Patients with LAA showed impairment of all parasympathetic tests (all P<0.05) and one of the sympathetic tests (mean fall in systolic blood pressure on standing: P = 0.058) and those with SVO only showed impairment in two parasympathetic tests (heart rate response to deep breathing: P = 0.010; heart rate response to standing: P = 0.004) in comparison with controls. Patients with LAA had significantly more impairment than those with SVO in some autonomic parameters (Valsalva ratio: P = 0.039; mean fall in systolic blood pressure on standing: P = 0.015).

Conclusions: Irrespective of the subtype of the ischemia, post-acute stroke patients showed a parasympathetic cardiac deficit. Additionally, parasympathetic and sympathetic cardiovascular modulations were more severely impaired in patients with LAA.

Keywords: Autonomic dysfunction; Infarction; Ischemic stroke; Large-artery atherosclerosis; Small-vessel occlusion; Stroke subtypes.