Is STA really a low‐flow graft? A quantitative ultrasonographic study of the flow of STA for cerebral revascularization in MMD patients

Clinical application of color Doppler ultrasound for assessing hemodynamic changes in the children with moyamoya disease undergoing combined revascularization surgery

Objective

To investigate the advantages of color Doppler ultrasound (CDUS) in detecting hemodynamic alterations in children with moyamoya disease (MMD) following combined revascularization surgery.

Methods

The common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA), and superficial temporal artery (STA) were measured by CDUS. Hemodynamic parameters including arterial diameter, peak systolic velocity (PSV), resistance index (RI), and blood flow volume (FV) were collected at three time points: pre-operation (T1), one week after operation (T2), and three months after operation (T3). Twelve children without intracranial arterial disease were recruited as the control group. Matsushima classification-based on digital subtraction angiography (DSA) was applied at T2.

Results

Among the 12 children with MMD, 11 patients with bilateral arterial stenosis and 1 patient with unilateral being affected. Compared to the 24 control hemispheres, the diameter of the ICA was significantly smaller in the 23 MMD hemispheres (p < 0.001) with an increased PSV of CCA and ECA, and a decrease FV of carotid arteries (p < 0.05). In MMD group, CDUS revealed increased diameter and FV, decreased RI of STA at the operative side at T2. The PSV and FV of ECA at the operative side increased from T1 to T3 (p < 0.05). Six cases were allocated to satisfactory compensation group (S Group, Matsushima classification grade A and B) and six cases to dissatisfactory compensation group (DS Group, Matsushima classification grade C). The increase in FV of STA on the operative side was higher in S Group at T2 than DS Group (Spearman rho = -0.693, p = 0.039).

Conclusion

As a noninvasive imaging modality, carotid and superficial temporal arteries ultrasound may serve as a valuable adjunct to invasive imaging techniques for children with MMD.

Technical Considerations for Optimizing Flow in Superficial Temporal Artery to Middle Cerebral Artery Bypass: Case Series

BACKGROUND AND OBJECTIVES

Cerebral bypass can provide flow augmentation for select patients with moyamoya disease (MMD) and steno-occlusive cerebrovascular disease (SOCD). Earlier work has suggested that sacrificing the nondonor branch of the superficial temporal artery (STA) can optimize direct flow, which we assessed in real time.

METHODS

This was a single-institution observational study of consecutive patients undergoing direct STA-middle cerebral artery (MCA) bypass with indirect encephalo-duro-myo-synangiosis for MMD and SOCD over 1 year. Excluding patients with significant STA-intracranial collateralization, the intraoperative effect of nondonor STA branch temporary occlusion on direct STA-MCA bypass flow was assessed using a Charbel flow probe. Patient characteristics and perioperative and postoperative data were reviewed.

RESULTS

Eleven patients (5 MMD, 6 SOCD; mean age 53.5 ± 15.3 years) underwent combined revascularization (4 left, 7 right). The mean donor STA branch flow increased from 4.91 ± 2.79 (baseline) to 16.63 ± 11.92 mL/min after anastomosis (95% CI 1.25-17.50; P = .015), and to 20.94 ± 10.63 mL/min after nondonor STA branch test occlusion (95% CI 1.71-6.90; P = .002). The parietal STA branch was used as the donor in 8 cases (72%). In 9 patients, the nondonor STA branch was sacrificed. Perioperatively, 1 patient experienced transient dysarthria/paresthesias (9.1%); there were no strokes or other major complications. The median hospital stay was 5.0 (IQR 4.0, 7.0) days, with 81% of patients discharged home. Over a mean follow-up of 6.2 ± 3.0 months, no patients had significant wound-healing issues, and the median modified Rankin Scale score improved from 2 (IQR 1.0, 2.5) preoperatively to 0 (IQR 0.0, 0.0) (95% CI 0.11-1.69; P < .015). Six-month angiography (available in 9 patients) demonstrated 100% direct bypass patency and a median direct bypass flow grade of 2.0 (IQR 2.0, 3.0).

CONCLUSION

In patients without STA-intracranial anastomoses, STA-MCA direct bypass flow may be optimized safely by nondonor STA branch sacrifice.

SDF-1/CXCR4 axis participants in the pathophysiology of adult patients with moyamoya disease

BACKGROUND

Moyamoya disease (MMD) is characterized by an abundance of moyamoya vessels; however, the precise mechanism driving the spontaneous angiogenesis of these compensatory vessels remains unclear. Previous research has established a link between the stromal cell-derived factor-1 (SDF-1)/ CXC receptor 4 (CXCR4) axis and angiogenesis under hypoxic conditions. Nevertheless, the alterations in this axis within the cerebrospinal fluid, arachnoid membranes and vascular tissue of MMD patients have not been fully investigated.

METHODS

Our study enrolled 66 adult MMD patients and 61 patients with atherosclerotic vascular disease (ACVD). We investigated the SDF-1 concentration in cerebrospinal fluid (CSF) and CXCR4 expression level on the arachnoid membranes and vascular tissue. We utilized enzyme-linked immunosorbent assay and immunohistochemistr. Additionally, we cultured and stimulated human brain microvascular endothelial cells (HBMECs) and smooth muscle cells (SMCs) under oxygen and glucose deprivation (OGD) conditions followed by reoxygenation, to examine any changes in the SDF-1/CXCR4 axis.

RESULTS

The results demonstrated an elevation in the level of SDF-1 in CSF among MMD patients compared to those with ACVD. Moreover, the expression of CXCR4 in arachnoid membranes and vascular tissue showed a similar trend. Furthermore, the content of CXCR4 in HBMECs and SMCs increased with the duration of ischemia and hypoxia. However, it was observed that the expression of CXCR4 decreased at OGD/R 24h compared to OGD 24h. The temporal pattern of SDF-1 expression in HBMECs and SMCs mirrored that of CXCR4 expression.

CONCLUSION

These findings indicate a critical role for the SDF-1/CXCR4 axis in the angiogenesis of moyamoya disease.

Usefulness of STA ultrasonography parameters after STA-MCA bypass in patients with moyamoya disease: A short review

STA bypass assessment by ultrasonography after bypass surgery in patients with moyamoya disease is minimally invasive and can be performed repeatedly. With STA bypass assessment by ultrasonography, it was shown that in the short term, blood flow that passes through the STA peaks approximately 5 days after the bypass surgery and then gradually decreases over 7 days. In the medium and long terms, it has been shown that the blood flow through the bypass decreases, compared with that during the first postoperative week, and continues for approximately half a year. The ultrasonographic STA parameters can also clearly indicate bypass patency, but there remains some discussion regarding bypass function. Although some reports have tried to show that these parameters are also useful for predicting acute-phase TNEs and predicting the future of bypass function, no studies have yet examined these parameters in detail in relation to the state of cerebral circulation or degree of residual antegrade flow, and additional studies are needed in the future.