Background and Purpose— External counterpulsation (ECP) is a novel noninvasive method used to improve the perfusion of vital organs, which may benefit ischemic stroke patients. We hypothesized that ECP may augment cerebral blood flow of ischemic stroke patients via induced hypertension. Methods— We recruited ischemic stroke patients with cerebral intracranial large artery occlusive disease and healthy elderly controls into this study. Bilateral middle cerebral arteries of subjects were monitored using transcranial Doppler. Flow velocity changes before, during, and after ECP were, respectively, recorded for 3 minutes while continuous beat-to-beat blood pressure data were recorded. Cerebral augmentation index was the increase in percentage of middle cerebral artery mean flow velocity during ECP compared with baseline. Transcranial Doppler data were analyzed based on ipsilateral or contralateral to the infarct side. Results— ECP significantly increased mean blood pressure of stroke patients and controls. During ECP, middle cerebral artery mean flow velocities of stroke patients increased on both ipsilateral and contralateral sides when compared with baseline (ipsilateral cerebral augmentation index, 9.64%; contralateral cerebral augmentation index, 9%; both P <0.001), but there was no increase in difference between the 2 sides when compared with each other. Mean flow velocities of controls did not change under ECP. After ECP, blood pressure and flow velocity of stroke patients returned to baseline level. Conclusion— ECP provides a new method of cerebral blood flow augmentation in ischemic stroke by elevation of blood pressure. Flow augmentation induced by ECP suggests the improvement of cerebral perfusion and collateral supply from infarct ipsilateral and contralateral sides.

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White matter lesions (WMLs) in normal elderly are related to chronic ischemia, and progression of WML occurs mostly in moderate to severe disease. However, the mechanism is uncertain. Thus, we enrolled fifty-six normal elderly patients without large artery disease. The severity of WML on MRI was graded as grade 0, I, II and III using the modified Fazekas scale. Cerebral blood flow (CBF) was measured by Xenon-CT. We found that CBF (mL/100 g/min) within periventricular lesions and in the right and left centrum semiovales were 20.33, 21.27 and 21.03, respectively, in group I; 16.33, 15.55 and 15.91, respectively, in group II; and 14.05, 14.46 and 14.23, respectively, in group III. CBF of normal-appearing white matter (NAWM) around periventricular areas and in the right and left centrum semiovales were 20.79, 22.26 and 22.15, respectively, in group 0; 21.12, 22.17 and 22.25, respectively, in group I; 18.02, 19.45 and 19.62, respectively, in group II; and 16.38, 18.18 and 16.74, respectively, in group III. Significant reductions in CBF were observed not only within lesions but also in NAWM surrounding the lesions. In addition, CBF was reduced significantly within lesions compared to NAWM of the same grade. Furthermore, CBF was reduced significantly in NAWM in grades II and III when compared to grades 0 and I. Our finding indicates that ischemia may play a role in the pathogenesis of WML. Additionally, our finding provides an alternative explanation for finding that the progression of WML occurred more commonly in patients with moderate to severe WML.

Background and PurposeExternal counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown.MethodsWe enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04–0.15 Hz), and high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated.ResultsWe found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035).ConclusionsECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies.

Blood pressure elevation persists throughout ECP treatment, which consists of 35 sessions. However, cerebral blood flow augmentation may last at least 3 weeks and then appears to return to baseline 1 month after acute stroke onset.

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ObjectivesExternal counterpulsation (ECP) is a non-invasive method being investigated for ischaemic stroke. We aimed to explore predictors of good functional outcome for ECP-treated ischaemic stroke patients who completed a minimum of 10 sessions.MethodsWe analysed our ECP registry of ischaemic stroke patients with cerebral large artery stenosis who underwent ECP therapy at the Prince of Wales Hospital from 2004 to 2010. We included 155 patients who completed at least 10 sessions of ECP and had 3-month follow-up data as well as 52 medical controls. Functional outcomes were dichotomised into good outcome (modified Rankin Scale (mRS) 0–2) and bad outcome (mRS 3–6). We compared the differences in two groups in terms of demographics, medical history and parameters of ECP treatment.ResultsAt 3 months after stroke, 70.5% of patients who finished the whole course of ECP had a good outcome (only 46.5% in the unfinished group and 38.5% in the medical group). Among all 207 recruited cases, 119 (57.5%) patients had a good outcome at 3 months after stroke. Compared with the bad outcome group, patients in the good outcome group were younger and had a lower baseline National Institutes of Health Stroke Scale (NIHSS) and longer ECP therapy duration. Multivariate logistic regression showed that ECP duration (OR 1.032), baseline NIHSS (OR 0.734) and age (OR 0.961) were independent predictors for a favourable outcome.ConclusionsDuration of ECP therapy is first found to be an important predictor for good outcome of ECP-treated ischaemic stroke patients, in addition to the well-known prognostic factors such as age and NIHSS.

ObjectiveExternal counterpulsation (ECP) is a non-invasive method used to augment cerebral blood flow of patients with ischaemic stroke via induced hypertension. We aimed to explore the correlation between the cerebral blood flow augmentation effects induced by ECP and clinical outcome after acute ischaemic stroke.MethodsWe retrospectively analysed our ECP registry of patients with ischaemic stroke who were enrolled within 7 days after stroke onset. Bilateral middle cerebral arteries of patients were monitored using transcranial Doppler (TCD). Flow velocity changes before, during and after ECP were, respectively, recorded for 3 min. The cerebral augmentation index (CAI) was the increase in percentage of the middle cerebral artery mean flow velocity during ECP compared with baseline. TCD data were analysed based on the side ipsilateral or contralateral to the infarct. The modified Rankin Scale (mRS) (good outcome: mRS 0∼2; poor outcome: mRS 3∼6) was evaluated 6 months after the index stroke.Results72 patients were included (mean age, 63.8±10.7 years; 87.5% males). At month 6 after stroke onset, univariate analysis showed that the National Institutes of Health Stroke Scale at recruitment was significantly higher and ECP therapy duration was longer in the poor outcome group, while the ipsilateral CAI was significantly lower in the good outcome group than that in the poor outcome group (3.71±4.94 vs 7.73±7.66, p=0.044). Multivariate logistic regression showed that ipsilateral CAI was independently correlated with an unfavourable functional outcome after adjusting for confounding factors.ConclusionsThe higher degree of cerebral blood flow velocity augmentation on the side ipsilateral to the infarct induced by ECP is independently correlated with an unfavourable functional outcome after acute ischaemic stroke.