Clinical Prediction of Surgical Revascularization Outcome in Moyamoya Disease Via Transcranial Color Sonography

Postoperative vascular event prediction using angiography and ultrasonography in patients with Moyamoya disease

OBJECTIVE

Indirect revascularization surgery reduce the risk of recurrent vascular events in patients with moyamoya disease (MMD), but the roles of postoperative angiography and ultrasonography in predicting these events remain unclear.

METHODS

This prospective study enrolled patients with MMD who would undergo their first unilateral indirect revascularization surgery. They received preoperative and postoperative ultrasound examination at 1, 3, and 6 months and conventional cerebral angiography. On ultrasonography, postoperative emerging flow (PEF) in an intracranial artery was defined as emerging flow postoperatively with absence of flow preoperatively. Predictors of vascular event frequency reduction were identified from angiographic and ultrasonographic parameters.

RESULTS

In total, 52 patients (including 24 pediatric and 24 male patients), who underwent 52 preoperative and 82 postoperative ultrasound examinations, were enrolled. Significant postoperative changes were noted in all the ultrasonographic parameters of ipsilateral superficial temporal artery (STA) and the end-diastolic velocity and flow volume in contralateral STA. During a median follow-up of 5.3 years, indirect revascularization surgery significantly reduced the occurrence of ipsilateral vascular events. Predictors of vascular event frequency reduction included Matsushima grade A or B on the ipsilateral side on angiography (odds ratio [OR] = 22.00, P = 0.002) and lower resistance index (RI) in ipsilateral STA (OR = 0.0001, P = 0.012) but no PEF pattern in ipsilateral middle cerebral artery (OR = 0.14, P = 0.029) on ultrasonography performed within 6 months.

CONCLUSIONS

Reduction of long-term vascular event frequency probably can be predicted through postoperative angiography and ultrasonography within 6 months after indirect revascularization surgery.

Presurgical Magnetic Resonance Imaging Indicators of Revascularization Response in Adults With Moyamoya Vasculopathy

BACKGROUND

Moyamoya is a progressive intracranial vasculopathy, primarily affecting distal segments of the internal carotid and middle cerebral arteries. Treatment may comprise angiogenesis-inducing surgical revascularization; however, lack of randomized trials often results in subjective treatment decisions.

HYPOTHESIS

Compensatory presurgical posterior vertebrobasilar artery (VBA) flow-territory reactivity, including greater cerebrovascular reactivity (CVR) and reduced vascular delay time, portends greater neoangiogenic response verified on digital subtraction angiography (DSA) at 1-year follow-up.

STUDY TYPE

Prospective intervention cohort.

SUBJECTS

Thirty-one patients with moyamoya (26 females; age = 45 ± 13 years; 41 revascularized hemispheres).

METHODS

Anatomical MRI, hypercapnic CVR MRI, and DSA acquired presurgically in adult moyamoya participants scheduled for clinically indicated surgical revascularization. One-year postsurgery, DSA was repeated to evaluate collateralization.

FIELD STRENGTH

3 T.

SEQUENCE

Hypercapnic T 2 * -weighted gradient-echo blood-oxygenation-level-dependent, T2 -weighted turbo-spin-echo fluid-attenuated-inversion-recovery, T1 -weighted magnetization-prepared-rapid-gradient-echo, and T2 -weighted diffusion-weighted-imaging.

ASSESSMENT

Presurgical maximum CVR and response times were evaluated in VBA flow-territories. Revascularization success was determined using an ordinal scoring system of neoangiogenic collateralization from postsurgical DSA by two cerebrovascular neurosurgeons (R.V.C. with 8 years of experience; M.R.F. with 9 years of experience) and one neuroradiologist (L.T.D. with 8 years of experience). Stroke risk factors (age, sex, race, vasculopathy, and diabetes) were recorded.

STATISTICAL TESTS

Fisher's exact and Wilcoxon rank-sum tests were applied to compare presurgical variables between cohorts with angiographically confirmed good (>1/3 middle cerebral artery [MCA] territory revascularized) vs. poor (<1/3 MCA territory revascularized) outcomes.

SIGNIFICANCE

two-sided P < 0.05. Normalized odds ratios (ORs) were calculated.

RESULTS

Criteria for good collateralization were met in 25 of the 41 revascularized hemispheres. Presurgical normalized VBA flow-territory CVR was significantly higher in those with good (1.12 ± 0.13 unitless) vs. poor (1.04 ± 0.05 unitless) outcomes. Younger (OR = -0.60 ± 0.67) and White (OR = -1.81 ± 1.40) participants had highest revascularization success (good outcomes: age = 42 ± 14 years, race = 84% White; poor outcomes: age = 49 ± 11 years, race = 44% White).

DATA CONCLUSION

Presurgical MRI-measures of VBA flow-territory CVR are highest in moyamoya participants with better angiographic responses to surgical revascularization.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 4.

The First 24 h Hemodynamic Management in NICU after Revascularization Surgery in Moyamoya Disease

Objective

To evaluate whether hemodynamic factors are risk factors for prognosis in moyamoya disease (MMD).

Materials and Methods

The retrospective study reviewed a single-center MMD cohort in Huashan Hospital from August 2017 to January 2020. Stroke events in 30 days and follow-up modified Rankin Scale (mRS) grade were recorded. Systematic assessments with perioperative mean arterial pressure (MAP), red blood cell (RBC) parameters, and fluid management were also conducted. Logistic regressions were applied to evaluate the predictors of worse outcomes. Data was analyzed using SPSS 24.0.

Results

Admission to neurological intensive care unit (NICU) totalled about 347 after revascularization surgery. The result showed that the higher the postoperative MAP level (favorable group 95.7 ± 11.4 mmHg vs. unfavorable group 103.6 ± 10.4 mmHg, p < 0.001) and the greater the MAP variability (favorable group 0.26 ± 13.2 vs. unfavorable group 7.2 ± 13.5, p = 0.006) were, the higher the patient's follow-up mRS grade was. What is more, a higher early postoperative Hb level also seemed to predict a worse long-term clinical outcome (favorable group 116.9 ± 17.1 g/L vs. unfavorable group 123.7 ± 13.0 g/L, p = 0.03), but the difference disappeared after adjusting sex and age. Logistic regression analyses showed that a higher level of postoperative MAP (β = 0.024, 95% CI (0.004, 0.044), and p = 0.02) within the first 24 h in NICU might be the short-term risk factor. For long-term outcome, a higher level (β = 1.058, 95% CI (1.022, 1.096), and p = 0.001) and a greater variability (β = 30.982, 95% CI (2.112, 454.414), and p = 0.01) of postoperative MAP might be the negative predictors of mRS grade.

Conclusions

The early postoperative hemodynamic management might be extremely critical for patients with MMD. Both high postoperative MAP levels and large MAP variability might affect the prognosis. What is more, we also found that a higher postoperative Hb level might be related with a worse outcome.