Pulsatility index of superficial temporal artery was associated with cerebral infarction after direct bypass surgery for moyamoya disease

OBJECTIVE

Direct bypass surgery by superficial temporal artery (STA) - middle cerebral artery anastomosis is an established procedure for moyamoya disease (MMD). However, some patients may develop cerebral infarction (CI) due to the watershed shift phenomenon after the surgery. This study sought to investigate the correlation between the postoperative changes of STA flow as well as cerebral blood flow (CBF) and the incidence of CI after direct bypass surgery for MMD.

METHODS

We conducted a retrospective study of 62 hemispheres in 50 subjects who underwent direct bypass surgery for MMD. All subjects underwent pre- and post-operative MR imaging, ultrasound evaluation of STA, and single-photon emission computed tomography. The presence of CI was correlated with preoperative CBF, the delta difference of each value of the STA between before and after the surgery, and the postoperative increase ratio of CBF.

RESULTS

All bypass procedures were patent, and CI was observed in 4 cases (6.4%). There was no significant association between the incidence of CI and both pre- and post-operative CBF. However, there was a significant difference in delta pulsatility index (PI) of the STA between cases with or without CI (-0.38±0.22 and -0.87±0.63, respectively, p=0.03). Whereas, other factors did not show any significant differences between those with or without CI.

CONCLUSIONS

A relatively high postoperative PI of the STA was significantly associated with the incidence of CI after direct bypass surgery for MMD. A larger study is needed to confirm these findings.

Association between Cognitive Decline and Altered Cerebral Perfusion in Adults with Moyamoya Disease after Revascularization

INTRODUCTION

Certain studies have observed that patients with moyamoya disease (MMD) have cognitive decline after revascularization. Thus, this study analyzed the relationship between cognitive decline and altered cerebral perfusion after revascularization.

METHODS

Here, 313 adult patients with MMD underwent single unilateral revascularization. First, cognitive function was scored using a Mini-Mental Scale (MMSE) and Montreal cognitive function scale (MoCA) before and 3 months after the operation (superficial temporal artery-middle cerebral artery anastomosis with encephalo-myo-synangiosis). Then, computed tomography perfusion was performed before and 1 week after the operation to assess the cerebral perfusion.

RESULTS

Our data showed that cognitive function decreased in 55 cases (17.6%) after revascularization. Furthermore, the incidence of cerebral hyperperfusion (CHP) was significantly higher in the cognitive decline group (49/55) than in the cognitive nondecline group (89.1% vs. 5.4%, p < 0.001). Results also showed that although all 55 patients had postoperative cognitive decline, 47 experienced relative cerebral blood flow (CBF) decrease at a relatively distant area of the anastomosis compared with that before the operation, which was significantly higher than in patients without cognitive decline (85.5% vs. 1.94%, p < 0.001). In addition, 41 patients had a simultaneous occurrence of local CHP and paradoxical CBF decrease at a relatively distant anastomosis area, which indicated the incident of watershed shift (WS). As observed, WS occurred in 74.5% of patients with cognitive decline, significantly higher than in patients without cognitive decline (74.5% vs. 0%, p < 0.0001). Through multiple logistic regression analysis, WS was also observed to be a strong independent risk factor for predicting postoperative cognitive decline 3 months after revascularization (odds ratio 17.780, 95% confidence interval 1.668-18.564; p = 0.017).

CONCLUSION

Therefore, cognitive decline in patients with MMD after revascularization is related to WS, leading to an uneven distribution of CBF.

Limb-shaking syndrome derived from the contralateral hemisphere following unilateral revascularisation for moyamoya disease

Background:

Moyamoya disease is a rare chronic steno-occlusive cerebrovascular disease. It may have variable clinical symptoms associated with cerebral stroke, including motor paralysis, sensory disturbances, seizures, or headaches. However, patients with moyamoya disease rarely present with involuntary movement disorders, including limb-shaking syndrome, with no previous reports of limb-shaking syndrome occurring after revascularization procedures for this disease. Although watershed shifts can elicit transient neurological deterioration after revascularisation, symptoms originating from the contralateral hemisphere following the revascularization procedure are rare. Here, we report the case of moyamoya disease wherein the patient developed limb-shaking syndrome derived from the contralateral hemisphere after unilateral revascularisation.

Case Description:

A 16-year-old girl presented with transient left upper and lower limb numbness and headache. Based on digital subtraction angiography, she was diagnosed with symptomatic moyamoya disease. Single-photon emission computed tomography (SPECT) showed decreased cerebral blood flow (CBF) on the right side, and she underwent direct and indirect bypasses on this side. Involuntary movements appeared in her right upper limb immediately postoperatively. SPECT showed decreased CBF to the bilateral frontal lobes. Subsequently, the patient was diagnosed with limb-shaking syndrome. After performing left-hemispheric revascularisation, the patient’s symptoms resolved, and SPECT imaging confirmed improvements in CBF to the bilateral frontal lobes.

Conclusion:

Revascularization for moyamoya disease can lead to watershed shifts, which can induce limb-shaking syndrome derived from abnormalities in the contralateral hemisphere of the revascularized side. For patients with new-onset limb-shaking syndrome after moyamoya revascularisation procedures, additional revascularization may be warranted for treatment of low perfusion areas.

Assessment of Transient Cerebral Hemodynamic Disturbance via Whole-Brain Computed Tomography Perfusion After Extracranial-Intracranial Bypass in Ischemic Moyamoya Disease

OBJECTIVE

To assess the cerebral hemodynamic data associated with transient cerebral hemodynamic disturbance (TCHD), including cerebral hyperperfusion syndrome (CHS) and watershed shift ischemia (WSI), by whole-brain (WB) computed tomography perfusion (CTP) before and after revascularization for ischemic moyamoya disease.

METHODS

A total of 115 consecutive patients with ischemic moyamoya disease underwent revascularization. All patients underwent WB-CTP 24 hours before operation and on the day of onset of TCHD and 6 months after revascularization. The volumes of delay time (DT) >3 seconds and mismatch and relative cerebral blood flow <30% were calculated in 3 time points.

RESULTS

Of the 115 patients, 18 115 had TCHD, comprising 10 with CHS and 8 with WSI. Compared with the brain volume of DT >3 seconds before revascularization, the volume decreased significantly (P < 0.05) on the day of CHS. The volume of mismatch in 3 time points indicated no significant differences (P > 0.05). The volume of relative cerebral blood flow <30% showed obvious differences of significance among 10 patients with CHS (P < 0.05) at 3 time points. In the WSI group, the volume of DT >3 seconds, mismatch, and DT >3 seconds showed significant differences, relatively (P < 0.05), at 3 time points. At the time of onset of TCHD, DT >3 seconds and mismatch in the CHS group were dramatically lower than those in the WSI group (P < 0.05). DT >3 seconds in the no-TCHD group showed significant differences (P < 0.05) at 3 time points.

CONCLUSIONS

WB-CTP could be used to assess the cerebral hemodynamic characteristics before and after revascularization. DT >3 seconds and mismatch played important roles in evaluating distinct features of TCHD.

Severe cerebral edema induced by watershed shift after bypass in a patient with chronic steno-occlusive disease: a case report and short literature review

Background

Carotid occlusive disease is a type of progressive disease resulting in ischemic stroke. Extracranial-intracranial bypass surgery represents a valid therapeutic option when medical treatment does not make effects. The appearance of cerebral edema following bypass is common during acute stage. Additionally, there are many causes of mild cerebral edema, such as hemodynamic changes, venous congestion and others. However, severe edema involving large brain tissue, which presents as reversible aphasia and hemiplegia, remains to be elucidated.

Case presentation

A 55-year-old man was admitted to the neurosurgery department for repeated dizziness for over a year and sudden onset of syncope 1 month prior, and he was diagnosed with carotid occlusive disease. After surgical contraindications were excluded, dual bypass and encephalo-duro-myo-synangiosis were performed. Although blood pressure and fluid management were strictly under control promptly after surgery, massive cerebral edema involving the left anterior cerebral artery and middle cerebral artery territories occurred from the 6th day after surgery. Additionally, no discernible cerebral infarction or hemorrhage occurred. Moreover, the cerebral blood flow of the middle cerebral artery displayed an early decrease followed by delayed elevation on the left side. Without restricting the spreading of cerebral edema, life-threatening cerebral herniation could develop at any time. Mannitol and furosemide were administered for impending cerebral herniation. The amelioration of symptoms was noticed on the 16th day after surgery. The patient felt relief on the 21st day after surgery. Digital subtraction angiography performed on the 180th day after surgery demonstrated the patency of dual anastomosed vessels, and the patient recovered without any permanent neurological deficit.

Conclusion

Based on changes in cerebral blood flow and reversible symptoms, the “watershed shift” phenomenon could explain such a severe deficit. However, this deficit was not the same as the classical presentation of the “watershed shift”, which involves a moderate amount of brain tissue and presents significant increases in cerebral blood flow. In addition to the “watershed shift”, a swollen temporal muscle may also participate in the progression of focal edema.