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Reduced blood flow is the principle pathophysiologic event in acute ischernic stroke.Hence,flow augmentation is the most important goal in stroke management.Improvement of cerebral blood flow can be accomplished by proximal arterial recanalization or by other systemic approaches.Diastolic counterpulsation is a non-invasive method to improve the perfusion of heart,kidneys and brain.This review summarizes the history,possible mechanism and the role of external counterpulsation in ischemic stroke.
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Objective To investigate short-term hemodynamic changes in selected patients with middle cerebral artery(MCA) stenting by transcranial Doppler sonography(TCD).Methods Stenting was given to 29 cases (31 MCAs) of patients with moderate and severe MCA stenosis if they had recurred symptoms during the standard antiplatelet therapy.TCD was applied to assess the hemodynamic changes in the stenosis segment and stenotic distal segment before stenting, 1 h and 3 d after stenting. Results Angiography showed that the rate of post-procedure residual stenoses of MCA were less than 20%.Compared with the pre-stentinng peak systolic velocity [PSV, (273±77)cm/s], the post-stenting PSV significantly decreased,which was (162±38) cm/s (P＜0.01) at 1 hour and (168±45)cm/s ( P＜0.01)at 3 days, respectively.Three cases (3 MCA) experienced recurrent stenosis-like spectra at stenosis segments 3 d after stenting and brain CT showed that 2 out of 3 cases suffered intracranial hemorrhage,which was potentially induced by hyperperfusion; PSV doubled in the stenotic distal segment in at least 28.6% patients.There was no statistic difference between pre- and post-stenting in the contralateral MCA (P＞0.05).Conclusions Stenting can dramatically improve the hemodynamic compromise of stenosis segments and their distal segments in selected patients with symptomatic MCA stenosis, however, potential hyperperfusion risk might he taken into consideration after MCA stenting.
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Objective To evaluate the best cutoff points of flow velocity for diagnosing and grading middle cerebral artery (MCA) stenosis as compared with magnetic resonance angiography (MRA) in a large group of asymptomatic patients. Methods We diagnosed 148 MCA stenostic patients with conventional method using EME-TC2000 transcranial Doppler (TCD) by a single reseach technician. All patients were given a MRA within 1 week after TCD examination. The severity of MCA stenosis was categorized as normal-mild (75% and void of flow signal) on the basis of the amount of signal loss and the lumen reduction of MCA in MRA . According to the different systolic velocities as following ≥130 cm/s, ≥140 cm/s , ≥150 cm/s, ≥160 cm/s, ≥ 170 cm/s, we drown different ROC(receiver operator characteristic) curves and determined which cutoff point was the best for diagnosing and grading the MCA stenosis.Results The numbers of vessel with normal, moderate and severe stenosis were 75, 112,109 respectively in MRA, their mean MCA velocities are (121?22) cm/s, (155?21) cm/s, (199?43) cm/s respectively in TCD, there was a obvious difference of systolic velocity among these three groups. Through calculating the bigest areas under ROC, we concluded that the optimal cutoff points for diagnosing MCA stenosis was 140 cm/s (areas under ROC was 0.87, P