Context: Physiological insights into blood flow alterations in cortical vessels after superficial
temporal artery-middle cerebral artery (STA-MCA) bypass surgery are important for
the prognosis of bypass sustainability and hemodynamic patency. Aims: This study aims to assess the impact of STA-MCA bypass on local hemodynamics for
patients with symptomatic carotid occlusions and Moyamoya disease. Settings and Design: This article presents a prospective nonrandomized study of intraoperative blood flow
measurements in cortical branches of MCA and donor vessel before and after cerebral
revascularization. Materials and Methods: Evaluation of local hemodynamic parameters was established for 112 patients with
symptomatic carotid occlusive disease and cerebrovascular insufficiency during STA-MCA
bypass surgery. We used intraoperative Doppler ultrasonography (89 patients – 72%),
flowmetry (56 cases – 50%), and in 33 cases both methods. For physical justification
of observed facts, we performed computational simulation with OpenFOAM CFD framework
using Navier-Stokes nonstationary hemodynamic model. Statistical Analysis Used: All calculations were performed with IBM SPSS Statistics version 10.0 software. We
used parametric (Z-test and Student's t-test) and nonparametric models (Wilcoxon,
Mann–Whitney). For categorical values, we used Fisher's exact test. Results: Local cerebral hemodynamics after revascularization surgery significantly depended
on initial perfusion deficit and the ability of bypass to reverse the blood flow in
proximal parts of cortical artery (86 cases, 77%). Mechanism of cortical blood flow
alteration was related to donor vessel cut flow value and potential consumption threshold
of acceptor artery. Conclusions: Knowledge of hemodynamic principles of flow redistribution after STA-MCA bypass is
important to improve bypass stainability and leads to better revascularization results.
Key-words:
Cerebral revascularization - extra-intracranial microanastomosis - ischemic stroke
- perfusion deficit
