Moyamoya syndrome: Impaired hemodynamics on ECD SPECT after EEG controlled hyperventilation

Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease

The present study examined whether preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease. Among 65 adult patients with ischemic moyamoya disease, 19 had misery perfusion in the precentral region on preoperative ¹⁵O positron emission tomography and underwent arterial bypass surgery for that region. Brain technetium-99 m-labeled ethyl cysteinate dimer single-photon emission computed tomography (SPECT) was preoperatively performed with and without hyperventilation challenge and relative cerebrovascular contractile reactivity to hypocapnia (RCVCR_hypocap) (%/mmHg) was calculated in the precentral region. Development of cerebral hyperperfusion syndrome was determined using perioperative changes of symptoms and brain N-isopropyl-p-[¹²³I]-iodoamphetamine SPECT performed after surgery. RCVCR_hypocap was significantly lower in the 6 patients with cerebral hyperperfusion syndrome (-2.85 ± 1.10%/mmHg) than in the 13 patients without cerebral hyperperfusion syndrome (0.18 ± 1.97%/mmHg; p = 0.0050). Multivariate analysis demonstrated low RCVCR_hypocap as an independent predictor of cerebral hyperperfusion syndrome (95% confidence interval, 0.04-0.96; p = 0.0433). Preoperatively reduced cerebrovascular contractile reactivity to hypocapnia by hyperventilation is associated with development of cerebral hyperperfusion syndrome after arterial bypass surgery for adult patients with cerebral misery perfusion due to ischemic moyamoya disease.

Rapid resolution of brain ischemic hypoxia after cerebral revascularization in moyamoya disease

BACKGROUND

In moyamoya disease (MMD), cerebral revascularization is recommended in patients with recurrent or progressive ischemic events and associated reduced cerebral perfusion reserve. Low-flow bypass with or without indirect revascularization is generally the standard surgical treatment. Intraoperative monitoring of cerebral partial pressure of oxygen (PtiO2) with polarographic Clark-type probes in cerebral artery bypass surgery for MMD-induced chronic cerebral ischemia has not yet been described.

OBJECTIVE

To describe basal brain tissue oxygenation in MMD patients before revascularization as well as the immediate changes produced by the surgical procedure using intraoperative PtiO2 monitoring.

METHODS

Between October 2011 and January 2013, all patients with a diagnosis of MMD were intraoperatively monitored. Cerebral oxygenation status was analyzed based on the Ptio2/PaO2 ratio. Reference thresholds of PtiO2/PaO2 had been previously defined as below 0.1 for the lower reference threshold (hypoxia) and above 0.35 for the upper reference threshold (hyperoxia).

RESULTS

Before STA-MCA bypass, all patients presented a situation of severe tissue hypoxia confirmed by a PtiO2/PaO2 ratio <0.1. After bypass, all patients showed a rapid and sustained increase in PtiO2, which reached normal values (PtiO2/PaO2 ratio between 0.1 and 0.35). One patient showed an initial PtiO2 improvement followed by a decrease due to bypass occlusion. After repeat anastomosis, the patient's PtiO2 increased again and stabilized.

CONCLUSION

Direct anastomosis quickly improves cerebral oxygenation, immediately reducing the risk of ischemic stroke in both pediatric and adult patients. Intraoperative PtiO2 monitoring is a very reliable tool to verify the effectiveness of this revascularization procedure.

Moyamoya disease: current concepts and future perspectives

Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

Clinical and videoEEG findings in a girl with juvenile moyamoya disease

Moyamoya disease is present throughout the course of development, including juvenile development. Very careful EEG analysis may be a diagnostic method in such cases where clinical symptoms are not sufficient for diagnosis. Herein, we report a Polish case of moyamoya disease in a 13-year-old girl with polymorphic clinical symptoms. Even though her diagnosis was made late in the course of her disease, it was due to successful EEG analysis and not due to clinical symptoms that a diagnosis was made at all. Re-build up phenomenon was registered as well as an asymmetric slowing in background activity. High-voltage slow frontal and generalized activity was seen during hyperventilation.