Intraoperative transit-time ultrasonography combined with FLOW800 predicts the occurrence of cerebral hyperperfusion syndrome after direct revascularization of Moyamoya disease: a preliminary study

Cerebral hemodynamic plasticity related to potential compensatory self-recirculation network in Moyamoya disease: an observational study

Moyamoya disease (MMD) suffers from impaired cerebrovascular hemodynamics and high perioperative complications occurrence. This study aims to propose and evaluate the relationship between intraoperative hemodynamics and perioperative complications, and propose a potential compensatory self-recirculation network in MMD. We prospectively enrolled 63 MMD patients undergone combined revascularization, and patients were divided into decreased and increased group according to decreased and increased microvascular transit time (MVTT), respectively. Mean age of all patients was 45.9 ± 9.4 years. The post-bypass hyperperfusion syndrome occurrence was significantly higher in the decreased MVTT group, and the cerebral infarction occurrence was significantly higher in the increased MVTT group. For the hemodynamics of the recipient artery around anastomosis, the parameters of distal site demonstrated a significant higher intensity and shorter time in the decreased MVTT group, while the parameters of the proximal site demonstrated a significant higher intensity and shorter time in the increased MVTT group. Pre-bypass and post-bypass collision of blood flow in artery and vein were firstly observed and illustrated. Intraoperative hemodynamics showed close relationship with perioperative complications. The blood flow of MMD seems to develop a unique compensatory self-recirculation system and contribute to the clinical complications, providing a new insight to the clinical management the pathology of the disease.

Individualised evaluation based on pathophysiology for moyamoya vasculopathy: application in surgical revascularisation

BACKGROUND

Although bypass surgery is an effective treatment for moyamoya vasculopathy (MMV), the incidence of postoperative complications is still high. This study aims to introduce a novel evaluating system based on individualised pathophysiology of MMV, and to assess its clinical significance.

METHODS

This multicentre, prospective study enrolled adult patients with MMV from Huashan Hospital, Fudan University and National Center for Neurological Disorders, China between March 2021 and February 2022. Multimodal neuroimages containing structural and functional information were used to evaluate personalised disease severity and fused to localise the surgical field, avoid invalid regions and propose alternative recipient arteries. The recipient artery was further selected intraoperatively by assessing regional haemodynamic and electrophysiological information. The preanastomosis and postanastomosis data were compared with assist with the postoperative management. Patients who received such tailored revascularisations were included in the novel group and the others were included in the traditional group. The 30-day surgical outcomes and intermediate long-term follow-up were compared.

RESULTS

Totally 375 patients (145 patients in the novel group and 230 patients in the traditional group) were included. The overall complication rate was significantly lower in the novel group (p˂0.001). In detail, both the rates of postoperative infarction (p=0.009) and hyperperfusion syndrome (p=0.010) were significantly lower. The functional outcomes trended to be more favourable in the novel group, though not significantly (p=0.260). Notably, the proportion of good functional status was higher in the novel group (p=0.009). Interestingly, the preoperative statuses of perfusion and metabolism around the bypass area were significantly correlated with the occurrence of postoperative complications (P˂0.0001).

CONCLUSIONS

This novel evaluating system helps to identify appropriate surgical field and recipient arteries during bypass surgery for MMV to achieve better haemodynamic remodelling and pathophysiological improvement, which results in more favourable clinical outcomes.

Application of intraarterial superselective indocyanine green angiography in bypass surgery for adult moyamoya disease

Background

Extracranial-intracranial (EC-IC) bypass surgery is the main treatment approach to moyamoya disease, and an accurate assessment of the patency of anastomosis is critical for successful surgery. So far, the most common way to do this is the intraoperative intravenous indocyanine green (ICG) video-angiography. Intra-arterial ICG-VA has been applied to treat peripheral cerebral aneurysms, spinal arteriovenous fistulas, and dural arteriovenous fistulas, but few reports have concerned the use of arterial injection of ICG to evaluate anastomotic patency. This research aims to explore the feasibility and effects of catheter-guided superficial temporal artery injection of ICG in the evaluation of anastomotic patency after bypass surgery.

Methods

In this study, 20 patients with moyamoya disease or syndrome who underwent bypass surgery were divided into two groups, one who received intravenous ICG angiography and the other who received intra-arterial ICG angiography, to compare the two injection methods for vascular anastomosis patency. We conducted conventional intraoperative digital subtraction angiography (DSA) in a hybrid operating room during extracranial-intracranial (EC-IC) bypass surgery, including the additional step of injecting ICG into the main trunk of the superficial temporal artery (STA) through a catheter.

Results

Intra-arterial injection of indocyanine green video-angiography (ICG-VA) indicated good patency of the vascular anastomosis when compared with conventional digital subtraction angiography (DSA) and intravenous ICG-VA, confirming the feasibility of using the arterial injection of ICG for assessing anastomotic patency. And intra-arterial ICG-VA results in faster visualization than intravenous ICG-VA (p < 0.05). Besides, ICG-VA through arterial injection provided valuable information on the vascular blood flow direction after the bypass surgery, and allowed for visual inspection of the range of cortical brain supply from the superficial temporal artery and venous return from the cortex. Moreover, arterial injection of ICG offered a rapid dye washout effect, reducing the repeat imaging time.

Conclusion

This study indicates that intra-arterial ICG-VA has good effects in observing the direction of blood flow in blood vessels and the range of cortical brain supply from the STA, which reflects blood flow near the anastomosis and provides additional information that may allow the postoperative prediction of cerebral hyperperfusion syndrome. However, the procedure of intra-arterial ICG-VA is relatively complicated compared to intravenous ICG-VA.

Multimodal evaluation of the bloodstream alteration before and after combined revascularization for Moyamoya disease

Objective

This study aimed to explore the hemodynamic changes before and after anastomosis in patients with Moyamoya disease (MMD) using multiple models.

Methods

We prospectively enrolled 42 MMD patients who underwent combined revascularization. Intraoperative FLOW800 was performed before and after anastomosis, and parameters was collected, including maximum intensity, delay time, rise time, slope, blood flow index, and microvascular transit time (MVTT). Additionally, preoperative and postoperative hemodynamic parameters were measured using color Doppler ultrasonography (CDUS), including peak systolic velocity, end-diastolic velocity, resistance index (RI), pulsatility index (PI), and flow volume. Subsequently, the correlation between FLOW800 and CDUS parameters was explored.

Results

A total of 42 participants took part with an average age of 46.5 years, consisting of 19 men and 23 women. The analysis of FLOW800 indicated that both the delay time and rise time experienced a substantial decrease in both the recipient artery and vein. Additionally, the MVTT was found to be significantly reduced after the surgery (5.7 ± 2.2 s vs. 4.9 ± 1.6, p = 0.021). However, no statistically significant differences were observed among the other parameters. Similarly, all postoperative parameters in CDUS hemodynamics exhibited significant alterations in comparison to the preoperative values. The correlation analysis between FLOW800 and CDUS parameters indicated a significant association between MVTT and RI and PI, no significant relationships were found among the other parameters in the two groups.

Conclusion

The hemodynamic outcomes of the donor and recipient arteries demonstrated significant changes following bypass surgery. The parameter of time appears to be more precise and sensitive in assessing hemodynamics using FLOW800. Multiple evaluations of hemodynamics could offer substantial evidence for perioperative management.

Intraoperative Hemodynamics of Parasylvian Cortical Arteries for Predicting Postoperative Symptomatic Cerebral Hyperperfusion after Direct Revascularization in Patients with Moyamoya Disease: A Preliminary Study

Objective. The search for methods by which to predict the risks of cerebral hyperperfusion syn-drome (CHS) in adults with moyamoya disease (MMD), including those utilizing new biomarkers, still deserves further research. The objective of this study was to investigate the association between the hemodynamics of parasylvian cortical arteries (PSCAs) and postoperative CHS. Methods. A consecutive number of adults with MMD who had undergone direct bypass between September 2020 and December 2022 were recruited. Intraoperative microvascular doppler ultrasonography (MDU) was performed to evaluate the hemodynamics of PSCAs. The intraoperative flow direction, mean value of velocity (MVV) of recipient artery (RA) and bypass graft were recorded. According to flow direction after bypass, RA was divided into entering sylvian (RA.ES) and leaving sylvian (RA.LS) subtypes. Univariate, multivariate, and ROC analyses of the risk factors for postoperative CHS were performed. Results. A total of 16 (15.09%) cases in 106 consecutive hemispheres (101 patients) sat-isfied the postoperative CHS criteria. According to univariate analysis, advanced Suzuki stage, MVV of RA before bypass, and fold increase of MVV in RA.ES after bypass were significantly associated with postoperative CHS (p < 0.05). Multivariate analysis indicated that left-operated hemisphere (OR (95%CI), 4.58 (1.05-19.97), p = 0.043), advanced Suzuki stage (OR (95%CI), 5.47 (1.99-15.05), p = 0.017), and fold increase of MVV in RA.ES (OR (95%CI), 1.17 (1.06-1.30), p = 0.003) were statistically significantly associated with the occurrence of CHS. The cut-off value of fold increase of MVV in RA.ES was 2.7-fold (p < 0.05). Conclusions. Left-operated hemisphere, advanced Suzuki stage, and postoperative fold increase of MVV in RA.ES were potential risk factors for postoperative CHS. Intraoperative MDU was useful for evaluating hemodynamics and predicting CHS.

Five-day bed rest reduces postoperative intracerebral hemorrhage after direct bypass for Moyamoya disease

OBJECTIVES

Postoperative intracerebral hemorrhage (ICH) after direct bypass surgery for Moyamoya disease (MMD) could contribute to neurological deterioration. The aim of this study was to evaluate the effectiveness of five-day bed rest in reducing the occurrence of postoperative ICH.

METHODS

This study included 122 consecutive hemispheres in 87 Japanese adult MMD patients, comprised of 80 control hemispheres from historical data and 42 hemispheres after five-day bed rest. They all underwent direct bypass surgery. The incidence of postoperative ICH and neurological deterioration assessed via the modified Rankin Scale (mRS) were investigated and statistically analyzed.

RESULTS

Postoperative ICH was observed in 9 out of the 80 (11.3%) control patients, but not in the 42 patients with five-day bed rest. The incidence of postoperative ICH and neurological deterioration via the mRS were significantly different between the two groups (p= 0.0268 and 0.0078, respectively). Univariate logistic analysis revealed that five-day bed rest significantly reduced the incidence of postoperative ICH (p= 0.0048).

CONCLUSIONS

Five-day bed rest after direct bypass surgery dramatically can reduce the incidence of postoperative ICH and neurological deterioration after direct bypass surgery.

Clinical Management of Moyamoya Patients

Moyamoya angiopathy (MMA) is a peculiar cerebrovascular condition characterized by progressive steno-occlusion of the terminal part of the internal carotid arteries (ICAs) and their proximal branches, associated with the development of a network of fragile collateral vessels at the base of the brain. The diagnosis is essentially made by radiological angiographic techniques. MMA is often idiopathic (moyamoya disease-MMD); conversely, it can be associated with acquired or hereditary conditions (moyamoya Syndrome-MMS); however, the pathophysiology underlying either MMD or MMS has not been fully elucidated to date, and this poor knowledge reflects uncertainties and heterogeneity in patient management. MMD and MMS also have similar clinical expressions, including, above all, ischemic and hemorrhagic strokes, then headaches, seizures, cognitive impairment, and movement disorders. The available treatment strategies are currently shared between idiopathic MMD and MMS, including pharmacological and surgical stroke prevention treatments and symptomatic drugs. No pharmacological treatment able to reverse the progressive disappearance of the ICAs has been found to date in both idiopathic and syndromic cases. Antithrombotic agents are usually prescribed in ischemic MMA, although the coexisting hemorrhagic risk should be considered. Surgical revascularization techniques, which are currently the best available treatment in symptomatic MMA, are associated with good long-term outcomes and reduced ischemic and hemorrhagic risks. Given the lack of dedicated randomized clinical trials, current treatment is mainly based on observational studies and physicians’ and surgeons’ expertise.