Effects and safety of aspirin use in patients after cerebrovascular bypass procedures

ObjectSuperficial temporal artery to middle cerebral artery (STA-MCA) bypass is the most effective treatment for Moyamoya disease (MMD). In this study, we aimed to assess whether aspirin improves STA-MCA bypass patency and is safe in patients with MMD.MethodsWe performed a retrospective medical record review of patients with ischaemic-onset MMD who had undergone STA-MCA bypass at two hospitals between January 2011 and August 2018, to clarify the effects and safety of aspirin following STA-MCA bypass. The neurological status at the last follow-up (FU) was compared between patients with FU bypass patency and occlusion.ResultsAmong 217 identified patients (238 hemispheres), the mean age was 41.4±10.2 years, and 51.8% were male; the indications for STA-MCA bypass were stroke (48.2%), followed by a transient ischaemic attack (44.0%). Immediate bypass patency was confirmed in all cases. During the FU period (1.5±1.5 y), 15 cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 94%. The patency rates were 93% and 94% in the short-term FU group (n=131, mean FU time 0.5±0.2 years) and long-term FU group (n=107, mean FU time 4.1±3.5 years), respectively. The STA-MCA bypass patency rate in the aspirin group was higher than that in the non-aspirin group (98.7% vs 89.7%; HR 1.57; 95% CI 1.106 to 2.235; p=0.012). No significant difference in the FU haemorrhagic events was observed between the aspirin and non-aspirin groups.ConclusionsAmong adult patients with ischaemic-onset MMD undergoing STA-MCA bypass procedures, aspirin might increase the bypass patency rate, without increasing the bleeding risk. FU bypass patency may be associated with a better outcome. Additional studies, especially carefully designed prospective studies, are needed to address the role of aspirin after bypass procedures.

Download Full-text

Clinical factors influencing the development of extracranial-intracranial bypass graft for steno-occlusive cerebrovascular disease

Neurosurgical FOCUS ◽

10.3171/2018.11.focus18500 ◽

2019 ◽

Vol 46 (2) ◽

pp. E5 ◽

Cited By ~ 3

Author(s):

Shunsuke Nomura ◽

Koji Yamaguchi ◽

Tatsuya Ishikawa ◽

Akitsugu Kawashima ◽

Yoshikazu Okada ◽

...

Keyword(s):

Diabetes Mellitus ◽

Cerebrovascular Disease ◽

Bypass Graft ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Long Term Results ◽

Main Trunk ◽

Factors Influencing ◽

Bypass Patency ◽

Significant Difference

OBJECTIVEEffectively retaining the patency of the extracranial-intracranial (ECIC) bypass is one of the most important factors in improving long-term results; however, the factors influencing bypass patency have not been discussed much. Therefore, the authors investigated factors influencing the development of the bypass graft.METHODSIn this retrospective study, the authors evaluated 49 consecutive hemispheres in 47 adult Japanese patients who had undergone ECIC bypass for chronic steno-occlusive cerebrovascular disease. To evaluate objectively the development of the ECIC bypass graft, the change in the area of the main trunk portion of the superficial temporal artery (STA) from before to after bypass surgery (postop/preop STA) was measured. Using the interquartile range (IQR), the authors statistically analyzed the factors associated with excellent (> 3rd quartile) and poor development (< 1st quartile) of the bypass graft.RESULTSThe postop/preop STA ranged from 1.08 to 6.13 (median 1.97, IQR 1.645–2.445). There was a significant difference in the postop/preop STA between the presence and absence of concurrent diabetes mellitus (p = 0.0432) and hyperlipidemia (0.0069). Furthermore, logistic regression analysis revealed that only concurrent diabetes mellitus was significantly associated with poor development of the bypass graft (p = 0.0235).CONCLUSIONSDiabetes mellitus and hyperlipidemia influenced the development of the ECIC bypass graft. In particular, diabetes mellitus is the only factor associated with poor development of the bypass graft.

Download Full-text

TachoSil Dural Reconstruction in Extracranial-Intracranial Bypass Surgeries

Journal of Neurological Surgery Part A Central European Neurosurgery ◽

10.1055/s-0038-1675565 ◽

2018 ◽

Vol 80 (01) ◽

pp. 039-043

Author(s):

Behnam Jahromi ◽

Christopher Ludtka ◽

Stefan Schwan ◽

Nakao Ota ◽

Hans Meisel ◽

...

Keyword(s):

Wound Healing ◽

Dura Mater ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Clotting Factors ◽

Bypass Patency ◽

Technical Report ◽

Csf Leakage ◽

Cerebrovascular Stroke

Background Superficial temporal artery to middle cerebral artery (STA-MCA) bypass is a treatment option for hemodynamic insufficiency in the anterior cerebral circulation. Complications associated with extracranial-intracranial bypass surgeries are ischemic strokes caused by bypass failure, wound-healing disorders, and further issues from cerebrospinal fluid (CSF) leakage. CSF leakage can provide pathways for infection. It is well known in general neurosurgery that watertight closure of the dura mater is necessary to prevent such complications. Objective To provide a technical description of TachoSil dural reconstruction in standard STA-MCA bypasses and their follow-up analyses. Methods In this technical report with observational follow-up, the dura mater was closed partially by adaptive sutures, and the perforation site of the donor vessel was sealed with TachoSil. TachoSil is a collagen sponge covered with clotting factors that provides hemostatic and sealing effects. Results Our study included eight cases of standard STA-MCA bypasses that had been operated between July 2015 and September 2016. Follow-up examinations were completed for all patients at 1 month and 6 months after surgery. Duplex and Doppler ultrasound demonstrated regular bypass patency in all patients without increased flow velocity at the perforation sites, which is a possible sign of stenosis. No wound-healing disorders or CSF leakage occurred. No cerebrovascular stroke events were observed. Conclusion Duraplasty with TachoSil enables the elastic reconstruction of the dura perforation gap in standard extracranial-intracranial bypass surgeries.

Download Full-text

Perfusion CT scanning and CT angiography in the evaluation of extracranial-intracranial bypass grafts

Journal of Neurosurgery ◽

10.3171/2010.6.jns10117 ◽

2011 ◽

Vol 114 (4) ◽

pp. 978-983 ◽

Cited By ~ 9

Author(s):

Soenke Langner ◽

Steffen Fleck ◽

Rebecca Seipel ◽

Henry W. S. Schroeder ◽

Norbert Hosten ◽

...

Keyword(s):

Computed Tomography ◽

Cerebrovascular Disease ◽

Bypass Surgery ◽

Superficial Temporal Artery ◽

Ct Scanning ◽

Temporal Artery ◽

Perfusion Ct ◽

Time To Peak ◽

Bypass Patency ◽

Before And After

Object Extracranial-intracranial (EC-IC) bypass surgery remains an important treatment alternative for patients with occlusive cerebrovascular disease. The aim of the present study was to use perfusion CT and CT angiography (CTA) to evaluate cerebral hemodynamics and bypass patency in patients with occlusive cerebrovascular disease before and after EC-IC bypass surgery. Methods Ten patients underwent perfusion CT and CTA before and after bypass surgery. Preoperative and postoperative digital subtraction angiography served as the diagnostic gold standard. An artery bypass was established from the superficial temporal artery to a cortical branch of the middle cerebral artery. Perfusion CT scanning was performed at the level of the basal ganglia. Color-coded perfusion maps of cerebral blood volume, cerebral blood flow, and time to peak were calculated. Results Preoperative perfusion CT showed significant prolonged time to peak and reduced cerebral blood flow of the affected hemisphere. Postoperative neurological deterioration did not develop in any patient. Computed tomography angiography provided adequate evaluation of the anastomoses as well as the course and caliber of the bypass and confirmed bypass patency in all patients. Postoperative perfusion CT showed improved cerebral hemodynamics with a return to nearly normal perfusion parameters. Conclusions Computed tomography angiography is a noninvasive and reliable tool for evaluating patients with EC-IC bypass. Perfusion CT allows monitoring of hemodynamic changes after bypass surgery. The combination of both modalities enables noninvasive anatomical and functional analysis of superficial temporal artery–middle cerebral artery anastomoses using a single CT protocol. Hemodynamic evaluation of patients with occlusive cerebrovascular disease before and after surgery may improve the prediction of outcome and may help identify patients in whom a bypass procedure can be performed.

Download Full-text

Extracranial-Intracranial Bypass and Vessel Occlusion for the Treatment of Unclippable Giant Middle Cerebral Artery Aneurysms

Neurosurgery ◽

10.1227/neu.0b013e3182804381 ◽

2012 ◽

Vol 72 (3) ◽

pp. 428-436 ◽

Cited By ~ 57

Author(s):

M. Yashar S. Kalani ◽

Joseph M. Zabramski ◽

Yin C. Hu ◽

Robert F. Spetzler

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Saphenous Vein Graft ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Parent Vessel ◽

Vessel Occlusion ◽

Bypass Patency ◽

The Mean

Abstract BACKGROUND: Giant middle cerebral artery (MCA) aneurysms pose management challenges. OBJECTIVE: To review the outcomes of patients with giant MCA aneurysms not amenable to clipping or vessel reconstruction treated with extracranial-intracranial (EC-IC) bypass and vessel sacrifice. METHODS: We retrospectively reviewed a database of aneurysms treated at our institution between 1983 and 2011. RESULTS: Sixteen patients (11 males, 5 females) were identified. There were 10 saccular, 4 fusiform, and 2 serpentine aneurysms. The aneurysms predominantly involved the M1 segment in 5 cases, M2 in 9 cases, and both M1 and M2 in 2 cases. The EC-IC bypasses performed included 13 superficial temporal artery-MCA, 1 saphenous vein graft-MCA, and 2 radial artery grafts-MCA. The postoperative bypass patency rate was 93.8% (15/16). There were 3 cerebrovascular accidents (18.8%), but no perioperative deaths (0% mortality). The mean follow-up was 58.4 months (range, 1-265; median, 23.5 months). In 75% (12/16) of cases the aneurysms were occluded successfully. A small residual was noted in 3 cases with the use of this treatment strategy, and they were re-treated. In a fourth case treated with partial distal occlusion, reduced flow through the aneurysm was noted postoperatively, but the patient did not undergo further treatment. The mean modified Rankin scale and mean Glasgow Outcome Scale scores at last follow-up were 1.6 (range, 1-4; median, 1) and 4.8 (range, 3-5; median, 5), respectively. CONCLUSION: Giant MCA aneurysms are challenging lesions. EC-IC bypass with parent vessel occlusion can provide a durable form of treatment with acceptable rates of morbidity and mortality.

Download Full-text

The oculomotor-tentorial triangle. Part 2: a microsurgical workspace for vascular lesions in the crural and ambient cisterns

Journal of Neurosurgery ◽

10.3171/2018.2.jns173141 ◽

2019 ◽

Vol 130 (5) ◽

pp. 1435-1445

Author(s):

Justin R. Mascitelli ◽

Sirin Gandhi ◽

Ali Tayebi Meybodi ◽

Michael T. Lawton

Keyword(s):

Cerebral Artery ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Vascular Pathology ◽

Vascular Lesions ◽

Oculomotor Nerve Palsy ◽

External Carotid ◽

Vertebrobasilar Insufficiency ◽

Cavernous Malformations ◽

Bypass Patency

OBJECTIVEPathology in the region of the basilar quadrifurcation, anterolateral midbrain, medial tentorium, and interpeduncular and ambient cisterns may be accessed anteriorly via an orbitozygomatic (OZ) craniotomy. In Part 1 of this series, the authors explored the anatomy of the oculomotor-tentorial triangle (OTT). In Part 2, the versatility of the OTT as a surgical workspace for treating vascular pathology is demonstrated.METHODSSixty patients with 61 vascular pathologies treated within or via the OTT from 1998 to 2017 by the senior author were retrospectively reviewed. Patients were grouped together based on pathology/surgical procedure and included 1) aneurysms (n = 19); 2) posterior cerebral artery (PCA)/superior cerebellar artery (SCA) bypasses (n = 24); 3) brainstem cavernous malformations (CMs; n = 14); and 4) tentorial region dural arteriovenous fistulas (dAVFs; n = 4). The majority of patients were approached via an OZ craniotomy, wide sylvian fissure split, and temporal lobe mobilization to widen the OTT.RESULTSAneurysm locations included the P1-P2 junction (n = 7), P2A segment (n = 9), P2/3 (n = 2), and basilar quadrification (n = 1). Aneurysm treatments included clip reconstruction (n = 12), wrapping (n = 3), proximal occlusion (n = 2), and trapping with (n = 1) or without (n = 1) bypass. Pathologies in the bypass group included vertebrobasilar insufficiency (VBI; n = 3) and aneurysms of the basilar trunk (n = 13), basilar apex (n = 4), P1 PCA (n = 2), and s1 SCA (n = 2). Bypasses included M2 middle cerebral artery (MCA)–radial artery graft (RAG)–P2 PCA (n = 8), M2 MCA–saphenous vein graft (SVG)–P2 PCA (n = 3), superficial temporal artery (STA)–P2 PCA (n = 5) or STA–s1 SCA (n = 3), s1 SCA–P2 PCA (n = 1), V3 vertebral artery (VA)–RAG–s1 SCA (n = 1), V3 VA–SVG–P2 PCA (n = 1), anterior temporal artery–s1 SCA (n = 1), and external carotid artery (ECA)–SVG–s1 SCA (n = 1). CMs were located in the midbrain (n = 10) or pontomesencephalic junction (n = 4). dAVFs drained into the tentorial, superior petrosal, cavernous, and sphenobasal sinuses. High rates of aneurysm occlusion (79%), bypass patency (100%), complete CM resection (86%), and dAVF obliteration (100%) were obtained. The overall rate of permanent oculomotor nerve palsy was 8.3%. The majority of patients in the aneurysm (94%), CM (93%), and dAVF (100%) groups had stable or improved modified Rankin Scale scores.CONCLUSIONSThe OTT is an important anatomical triangle and surgical workspace for vascular lesions in and around the crural and ambient cisterns. The OTT can be used to approach a wide variety of vascular pathologies in the region of the basilar quadrifurcation and anterolateral midbrain.

Download Full-text

Double-Barrel Superficial Temporal Artery-M2 Middle Cerebral Artery Bypass and Creation of a Middle Communicating Artery via M2-M2 End-to-End Reimplantation for Trapping of a Dolichoectatic Middle Cerebral Artery Aneurysm: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opaa159 ◽

2020 ◽

Vol 19 (5) ◽

pp. E521-E522

Author(s):

Joshua S Catapano ◽

Fabio A Frisoli ◽

Megan S Cadigan ◽

Dara S Farhadi ◽

Candice L Nguyen ◽

...

Keyword(s):

Family History ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Aneurysmal Subarachnoid Hemorrhage ◽

Superficial Temporal Artery ◽

Artery Aneurysm ◽

Temporal Artery ◽

Bypass Patency ◽

History Of ◽

End To End

Abstract Large dolichoectatic aneurysms of middle cerebral artery (MCA) trifurcations are rare and often require trapping and revascularization of the region with a bypass.1-9 This video describes the treatment of an MCA trifurcation aneurysm by clip trapping and double-barrel superficial temporal artery (STA) to M2-MCA bypass followed by M2-M2 end-to-end reimplantation to create a middle communicating artery (MCoA). The patient, a 60-yr-old woman, presented with headache, a history of smoking, and a family history of ruptured aneurysms. Angiography demonstrated a 1.7-cm dolichoectatic aneurysm of the MCA trifurcation. While the natural history of these lesions is unclear, the aneurysm size and family history of aneurysmal subarachnoid hemorrhage were factors in proceeding with treatment. Informed written consent was obtained from the patient and her family. The STA branches were harvested microsurgically, a pterional craniotomy was performed, and the aneurysm was exposed through a transsylvian approach. The two STA branches were anastomosed end-to-side to the middle and inferior trunks of the MCA. Due to the significant mismatch between the donor and recipient vessel calibers, we were concerned that the donors might provide insufficient flow in isolation. Therefore, we decided to transect both M2 trunks from the aneurysm, proximal to the inflow of the bypass, and reimplant them end-to-end. This reimplantation created an MCoA, allowing the two donor arteries to supply the new communication between the inferior and middle trunks, redistributing blood flow through the MCoA according to cerebral demand. Bypass patency and aneurysm obliteration were confirmed on postoperative angiography. At the 6-mo follow-up, the patient's modified Rankin Scale (mRS) score was 0. The MCoA is a novel construct that, like natural communicating arteries, redistributes flow in response to shifting demand, without the need for additional ischemia time during the bypass. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Download Full-text

Bonnet Bypass for Left Superficial Temporal Artery Bifurcation to Right Middle Cerebral Artery: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opz245 ◽

2019 ◽

Vol 17 (5) ◽

pp. E201-E202 ◽

Cited By ~ 1

Author(s):

Benjamin K Hendricks ◽

Robert F Spetzler

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Saphenous Vein ◽

Superficial Temporal Artery ◽

Video Recording ◽

Temporal Artery ◽

Interposition Graft ◽

Institutional Review ◽

Bypass Patency ◽

Pass Through

Abstract A bonnet bypass is a long interposition graft bypass used for extracranial to intracranial revascularization, which is useful in patients who do not have a suitable ipsilateral donor or in whom the ipsilateral donor must be sacrificed. This interposition graft is commonly the radial artery or saphenous vein. The only practical difference in this technique for revascularization is that an interposition graft must pass through the subgaleal space to the contralateral scalp to allow for reimplantation at the desired contralateral point of anastomosis. This patient underwent a bonnet bypass for revascularization of the middle cerebral artery (MCA) perfusion territory utilizing the contralateral superficial temporal artery (STA). A saphenous vein was used as the interposition graft, which was anastomosed to an M2 segment bifurcation. The graft was then temporarily occluded and passed within a calvarial trough to the contralateral frontoparietal region. The graft was then anastomosed to the contralateral STA at a bifurcation to accommodate the graft size mismatch. The patient tolerated the bypass procedure well and demonstrated bypass patency on postoperative angiographic imaging. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Download Full-text

The Value of the Middle Meningeal Artery in Cerebrovascular Bypass Surgery: An Anatomic Feasibility Study

Operative Neurosurgery ◽

10.1093/ons/opx200 ◽

2017 ◽

Vol 15 (1) ◽

pp. 89-96 ◽

Cited By ~ 3

Author(s):

Hamid Reza Niknejad ◽

Albert van der Zwan ◽

Sam Heye ◽

Frank Van Calenbergh ◽

Johannes Van Loon

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Middle Meningeal Artery ◽

External Carotid ◽

Silicone Injection ◽

Significant Difference ◽

Cerebrovascular Surgery ◽

Meningeal Artery

Abstract BACKGROUND Over the past decade, there has been a revival and a renewed interest for cerebrovascular bypass procedures. The superficial temporal artery (STA) has its value as a reliable donor vessel; however, a possible role for the middle meningeal artery (MMA) as a donor artery is still unclear. OBJECTIVE To assess the feasibility of using the MMA as a donor vessel in cerebrovascular surgery. METHODS We performed cadaveric dissections on 12 fresh specimens (23 sides) after bilateral silicone injection into the internal and external carotid arteries. We compared the size, diameter, and possibility to perform a bypass to the middle cerebral artery for both the MMA and the STA. Measurements were done using an electrical caliper. Additional measurements of the MMA and STA were performed on 20 random angiograms. RESULTS There was no statistically significant difference in diameter of the MMA at its ostium being 2.4 mm, compared to 2.7 mm for the STA ostium (t-test; P = .21). The MMA could be mobilized over 4.1 cm, whereas the STA over 8.3 cm. Finally, the mean diameter of the donor vessel at the site of the anastomosis was 1.6 mm versus 1.9 mm for MMA and STA, respectively (P = .0026). We were able to perform an MMA and middle cerebral artery anastomosis on 17 sides. CONCLUSION These results suggest that the MMA is a potentially valuable donor vessel to be used in selected cases. The availability of a suitable MMA branch should be assessed preoperatively on the angiogram.

Download Full-text

ICG Flow 800 technology targeted STA-MCA microvascular bypass for exclusion of deep-seated fusiform MCA aneurysm: 2-dimensional operative video

Neurosurgical Focus: Video ◽

10.3171/2021.10.focvid21183 ◽

2022 ◽

Vol 6 (1) ◽

pp. V14

Keyword(s):

Blood Flow ◽

Open Surgery ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Digital Subtraction ◽

Bypass Patency ◽

Before And After ◽

Mca Aneurysm ◽

Flow 800 ◽

Temporary Clipping

The authors present the case of an 18-year-old male with a deep-seated left fusiform dissecting M3 aneurysm for which endovascular treatment was not applicable. At the open surgery, they used the less commonly reported FLOW 800 fluorescent indocyanine green (ICG) videoangiography, before and after parental aneurysmal artery temporary clipping, to locate the distal outflow branch of the aneurysm and use it as the recipient artery for a superficial temporal artery–M4 bypass, excluding the aneurysm by clipping the parental artery. Repeated ICG FLOW 800 angiography confirmed bypass patency and adequate blood flow. The aneurysm’s exclusion from circulation was confirmed by digital subtraction angiography postoperatively. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21183

Download Full-text

Blood volume flow in the superficial temporal artery assessed by duplex sonography: predicting extracranial-intracranial bypass patency in moyamoya disease

Journal of Neurosurgery ◽

10.3171/2020.9.jns202709 ◽

2021 ◽

pp. 1-8

Author(s):

Florian Connolly ◽

Joan Alsolivany ◽

Marcus Czabanka ◽

Peter Vajkoczy ◽

Jose M. Valdueza ◽

...

Keyword(s):

Moyamoya Disease ◽

Superficial Temporal Artery ◽

Type A ◽

Temporal Artery ◽

Duplex Sonography ◽

External Carotid Artery ◽

External Carotid ◽

Catheter Angiography ◽

Type B ◽

Bypass Patency

OBJECTIVE Superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery is an important therapy for symptomatic moyamoya disease. Its success depends on bypass function, which may be impaired by primary or secondary bypass insufficiency. Catheter angiography is the current gold standard to assess bypass function, whereas the diagnostic value of ultrasonography (US) has not been systematically analyzed so far. METHODS The authors analyzed 50 STA-MCA bypasses in 39 patients (age 45 ± 14 years [mean ± SD]; 26 female, 13 male). Bypass patency was evaluated by catheter angiography, which was performed within 24 hours after US. The collateral circulation through the bypass was classified into 4 types as follows: the bypass supplies more than two-thirds (type A); between one-third and two-thirds (type B); or less than one-third (type C) of the MCA territory; or there is bypass occlusion (type D). The authors assessed the mean blood flow velocity (BFV), the blood volume flow (BVF), and the pulsatility index (PI) in the external carotid artery and STA by duplex sonography. Additionally, they analyzed the flow direction of the MCA by transcranial color-coded sonography. US findings were compared between bypasses with higher (types A and B) and lower (types C and D) capacity. RESULTS Catheter angiography revealed high STA-MCA bypass capacity in 35 cases (type A: n = 22, type B: n = 13), whereas low bypass capacity was noted in the remaining 15 cases (type C: n = 12, type D: n = 3). The BVF values in the STA were 60 ± 28 ml/min (range 4–121 ml/min) in the former and 12 ± 4 ml/min (range 6–18 ml/min) in the latter group (p < 0.0001). Corresponding values of mean BFV and PI were 57 ± 21 cm/sec (range 16–100 cm/sec) versus 22 ± 8 cm/sec (range 10–38 cm/sec) (p < 0.0001) and 0.8 ± 0.2 (range 0.4–1.3) versus 1.4 ± 0.5 (range 0.5–2.4) (p < 0.0001), respectively. Differences in the external carotid artery were less distinct: BVF 217 ± 71 ml/min (range 110–425 ml/min) versus 151 ± 41 ml/min (range 87–229 ml/min) (p = 0.001); mean BFV 47 ± 17 cm/sec (range 24–108 cm/sec) versus 40 ± 7 cm/sec (range 26–50 cm/sec) (p = 0.15); PI 1.5 ± 0.4 (range 1.0–2.5) versus 1.9 ± 0.4 (range 1.2–2.6) (p = 0.009). A retrograde blood flow in the MCA was found in 14 cases (9 in the M1 and M2 segment; 5 in the M2 segment alone), and all of them showed a good bypass function (type A, n = 10; type B, n = 4). The best parameter (cutoff value) to distinguish bypasses with higher capacity from bypasses with lower capacity was a BVF in the STA ≥ 21 ml/min (sensitivity 100%, negative predictive value 100%, specificity 91%, positive predictive value 83%). CONCLUSIONS Duplex sonography is a suitable diagnostic tool to assess STA-MCA bypass function in moyamoya disease. Hemodynamic monitoring of the STA by US provides an excellent predictor of bypass patency.

Download Full-text