Hemodynamic changes of donor artery after combined revascularization in adult Moyamoya disease

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.

Assessment of donor-vessel after STA-MCA bypass for moyamoya disease using handheld Doppler to confirm bypass patency and predict perioperative hyperperfusion

The study included 12 hemispheres of 9 patients with moyamoya disease who underwent direct-indirect revascularization. The parameters (peak systolic velocity (PSV), mean flow velocity (MV), resistance index (RI), flow volume (FV)) of the superficial temporal artery (STA) on the operated side were measured using a handheld Doppler before and after surgery in all the patients. The examination was conducted in a similar manner on postoperative day (POD)1 on 9 sides of 7 patients except for 3 sides of the first 2 patients. Patency of the superficial temporal artery-middle cerebral artery (STA-MCA) bypass was confirmed by magnetic resonance angiography (MRA) performed on all 12 sides of 9 patients within the first 2 PODs. There was a statistically significant increase in the PSV (p = 0.0201) and the MV (p = 0.0110) and a decrease in the RI (p = 0.0177) in the STA after surgery when compared with those measured before surgery. None of the changes from the immediate postoperative period to POD1 were statistically significant. Postoperative transient neurological events (TNEs) occurred in 3 patients (25 %) in the first 2 weeks, and all of them were attributed to hyperperfusion. The FV of the three sides associated with TNEs was significantly higher than that of the nine sides that were not (p = 0.0273). From the early stage after moyamoya disease bypass surgery, it was clarified that the parameter of the STA changed in which the PSV and the MV increased and the RI decreased. It was clarified that the increase in the FV, which is the blood flow rate that flows through the STA in the immediate postoperative period, may be a predictor of the development of hyperperfusion during the perioperative course.

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.

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.