Dynamic Cerebral Autoregulation Is Heterogeneous in Different Subtypes of Acute Ischemic Stroke

Zhen-Ni Guo,Yi Yang,Hang Jin,Yingqi Xing,Cunling Lv,Shuo Yan,Jia Liu,Mathias Gelderblom

doi:10.1371/journal.pone.0093213

Abstract

Background and PurposeStroke of large-artery atherosclerosis and small-artery occlusion are two main subtypes of stroke according to TOAST classification. The underlying mechanisms of how these two subtypes affect dynamic cerebral autoregulation (dCA) might be heterogeneous, resulting in varied clinical conditions and outcomes. We therefore studied the pattern of dCA in these two subtypes.MethodsForty-one patients with acute unilateral middle cerebral artery (MCA) territory stroke (15 with ipsilateral large-artery atherosclerosis and 26 with small-artery occlusion) and 20 healthy volunteers were enrolled. Non-invasive continuous cerebral blood flow velocity and arterial blood pressure were recorded simultaneously from each subject in supine position using transcranial Doppler on MCA bilaterally and servo-controlled plethysmograph on the middle finger, respectively. Transfer function analysis was applied to derive autoregulatory parameters, gain, phase difference (PD), and slope of step response.ResultsIn the large-artery atherosclerosis group, PD in affected hemisphere was 42.9±18.5 degree, which is significantly lower than the unaffected hemisphere (72.4±29.9 degree, P<0.01), and the healthy group (P<0.01). However, PD is similar in the unaffected hemisphere and healthy group (P>0.1). In the small-artery occlusion group, PD in the affected hemisphere was similar to that in the contralateral hemisphere (33.8±17.9 vs. 32.6±21.1 degree, P>0.1), both sides were significantly lower than the healthy group (all P<0.001).The results of the slope of step response agree with the findings in PD.ConclusionsDCA in different subtypes of acute ischemic stroke is heterogeneous, which might be attributed to the varied pathologic changes of cerebral blood vessels.

Highlights

Dynamic cerebral autoregulation is likely affected in acute ischemic stroke[1,2,3]
In large-artery stenosis, previous studies suggested that hemodynamics in ipsilateral side is altered due to the reduction of the effectiveness of vasodilation as the related vessels may have already dilated in compromise of hypoperfusion[5,6]
Stenosis $50% of the middle cerebral artery (MCA) was determined by a mean velocity. 100 cm/s; stenosis $70% of the MCA was determined by a mean velocity .120 cm/s in TCD[9], the results of magnetic resonance angiography (MRA) was used as a reference

Summary

Introduction

Dynamic cerebral autoregulation (dCA) is likely affected in acute ischemic stroke[1,2,3]. Large-artery atherosclerosis and small-artery occlusion (lacune) are considered as the most common subtypes of acute ischemic stroke[4]. The underlying mechanisms of how these cerebrovascular diseases affect cerebral hemodynamics might be heterogeneous, resulting in varied clinical conditions and outcomes. In small-artery occlusion, the changes of hemodynamics are more diffuse as the causes of cerebral small vessel diseases, such as hypertension, diabetes, and etc[7,8], are normally chronic, which might affect dCA bilaterally. Stroke of large-artery atherosclerosis and small-artery occlusion are two main subtypes of stroke according to TOAST classification. The underlying mechanisms of how these two subtypes affect dynamic cerebral autoregulation (dCA) might be heterogeneous, resulting in varied clinical conditions and outcomes. We studied the pattern of dCA in these two subtypes

Methods

Results

Conclusion