Intraoperative Blood Flow Analysis of Direct Revascularization Procedures in Patients with Moyamoya Disease

Abstract

Moyamoya disease is characterized by the progressive stenosis and often occlusion of the terminal internal carotid arteries, which leads to ischemic and hemorrhagic injuries. The etiology is unknown and surgical revascularization remains the mainstay treatment. We analyzed various hemodynamic factors in 292 patients with moyamoya disease, representing 496 revascularization procedures, including vessel dimension and intraoperative blood flow, using a perivascular ultrasonic flowprobe. Mean middle cerebral artery (MCA) flow rate was 4.4 ± 0.26 mL/min. After superficial temporal artery (STA)-MCA bypass surgery, flows at the microanastomosis were increased fivefold to a mean of 22.2 ± 0.8 mL/min. The MCA flows were significantly lower in the pediatric (16.2 ± 1.3 mL/min) compared with the adult (23.9 ± 1.0 mL/min; P<0.0001) population. Increased local flow rates were associated with clinical improvement. Permanent postoperative complications were low (<5%), but very high postanastomosis MCA flow was associated with postoperative stroke (31.2 ± 6.8 mL/min; P=0.045), hemorrhage (32.1 ± 10.2 mL/min; P=0.045), and transient neurologic deficits (28.6 ± 5.6 mL/min; P=0.047) compared with controls. Other flow and vessel dimension data are presented to elucidate the hemodynamic changes related to the vasculopathy and subsequent to surgical intervention.

Neurosurgical Advances in the Treatment of Moyamoya Disease

“…We analyzed various hemodynamic factors in 292 patients with MMD using this perivascular flow probe. 33 After anastomosis, middle cerebral artery flow increased on average 5-fold. Very high postanastomotic middle cerebral artery flow was associated with postoperative ischemic stroke and hemorrhage and transient neurological deficit.…”

“…In our study, high postanastomotic middle cerebral artery flow significantly correlated with hemorrhage, transient neurological deficits, and perioperative ischemia. 33 An important consideration in the postoperative management of patients with MMD is the concept of hyperperfusion causing transient or permanent neurological deficits. This complication is well known in carotid endarterectomy and high-flow bypasses; however, it has been increasingly described in low-flow STA-MCA bypasses.…”

Clinical and angiographic outcomes after combined direct and indirect bypass in adult patients with moyamoya disease: A retrospective study of 76 procedures

“…Previous studies reported that STA-MCA bypass increases STA and MCA blood flow during the early vascular remodeling period (14,15). The increase of STA blood flow may be associated with the low resistance of the intracranial vascular bed, while the increase of MCA blood flow may be due to the support of the STA.…”

“…Intracranial and extracranial vascular reconstruction surgery mainly includes direct and indirect revascularization. Direct revascularization increases the cerebral blood flow and instantly improves cerebral metabolism (14,15), but the drawback is that STA or MCA branches of moyamoya patients may be fragile and easily occluded; thus, the long-term effect of direct revascularization remains elusive. In addition, patients with direct revascularization are prone to developing cerebral hemodynamic disturbances and perioperative complications (16).…”

Electroencephalographic features of moyamoya in adults

“…Elevated blood flow in this setting is associated with postoperative complications, including transient neurologic events (Lee et al, 2011b) and impaired autoregulation (Chen et al, 2013). The retrospective design of this study did not allow assessment of post-anastomosis flow.…”