Delayed reopening of a superficial temporal artery to middle cerebral artery bypass graft occluded by a white thrombus during surgery

Abstract

Background: To the authors’ knowledge, reopening of a superficial temporal artery to middle cerebral artery (STA-MCA) bypass graft occluded by a white thrombus during the procedure and was observed several months after the surgery is relatively rare. Case Description: The authors encountered a case of moyamoya disease in an Asian female in her third decade of life, in whom a bypass recipient vessel was occluded by a white thrombus during surgery and remained occluded on magnetic resonance angiography (MRA) performed up to 6 weeks after the procedure. However, recanalization was confirmed by MRA performed 4 months after surgery. MRA performed 10 and 19 months after surgery revealed that the bypass vessel had grown thicker, and the ischemic symptoms experienced by the patient also improved. Conclusion: Whether this lesion is explained by reopening or angiogenesis, its pathophysiology remains controversial. The uninterrupted connection of occluded bypass vessel in STA-MCA bypass surgery in conjunction with surgical strategy of single bypass using only parietal branch of STA as donor and preserving blood flow of frontal branch to scalp may have made a positive impact on promoting the development of extracranial-intracranial bypass anastomosis in the chronic phase and should be considered.

The preoperative focal cerebral blood flow status may be associated with slow flow in the bypass graft after combined surgery for moyamoya disease

“…As discussed in a previous study, some reports of the appearance of white thrombi during surgery for STA-MCA bypass have already been reported. [14,22,33] When analyzed for the appearance of white thrombi during the operation, Mikami et al [22] stated that higher MRA scores were significantly associated with thrombogenesis. [18] As part of a discussion based on this finding, it is a remarkable anatomical structure indicating that the recipient artery on the brain surface is fragile and thin in patients with advanced MMD presenting with higher MRA scores.…”

“…Some investigations reporting that the occluded bypass was recanalized in all cases prompted us to investigate this issue. [ 17 , 33 ] Regarding bypass occlusion using a vein graft in EC to IC bypass, a report from an Australian group is a powerful reference. [ 30 ] The authors proved that the flow rate specified for mean arterial pressure should not fall below a minimum of 40 ml/min to maintain blood flow for bypass based on the study by Sundt and Sundt.…”

“…Although several studies have been conducted on early postoperative bypass occlusion with STA-MCA bypass for occlusive cerebrovascular disease due to cerebral atherosclerosis, quite few reports are available on early postoperative bypass occlusion for that procedure in patients with MMD. Takahashi and Yoshida[ 33 ] reported a case, in which a white thrombus appeared during STA-MCA bypass surgery for an Asian female patient with MMD, and the bypass was occluded but recanalized 4 months after surgery. In their case report, recanalization was obtained by removing the white thrombus that occurred during the operation by reopening the anastomosis, but bypass patency was not finally confirmed by ICG video angiography.…”

“…As discussed in a previous study, some reports of the appearance of white thrombi during surgery for STA-MCA bypass have already been reported. [ 14 , 22 , 33 ] When analyzed for the appearance of white thrombi during the operation, Mikami et al . [ 22 ] stated that higher MRA scores were significantly associated with thrombogenesis.…”

“…is event is very rare and has seldom been verified. [17,33] e pressure gradient between the donor and the recipient and the radius of the conduit plays an important role in the patency of the bypass. [30,31] When considering the patency of direct bypass from the external carotid artery (ECA) system to the ICA system, the pressure difference with the ECA system should be considered.…”