Prediction of cerebral infarction after bypass surgery in adult moyamoya disease: using pulsatility index on TCD

Abstract

Background: At present, the most effective treatment for symptomatic moyamoya disease (MMD) is surgery. However, the high incidence of postoperative complications is a serious problem plaguing the surgical treatment of MMD, especially the acute cerebral infarction. Decreased cerebrovascular reserve is an independent risk factor for ischemic infarction, and the pulsatility index (PI) of transcranial Doppler (TCD) is a common intuitive index for evaluating intracranial vascular compliance. However, the relationship between PI and the occurrence of ischemic stroke after operation is unclear.

Objective: To explore whether the PI in the middle cerebral artery (MCA) could serve as a potential predictor for the occurrence of ischemic infarction after bypass surgery in MMD.

Methods: We performed a retrospective analysis of data from 71 patients who underwent combined revascularization surgery, including superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-synangiosis (EDMS). The patients were divided into two groups according to the median of ipsilateral MCA-PI before operation, low PI group (MCA-PI < 0.614) and high PI group (MCA-PI ≥ 0.614). Univariate and multivariate regression analysis were used to explore risk factors affecting the occurrence of postoperative cerebral infarction.

Results: Among the 71 patients with moyamoya disease, 11 patients had cerebral infarction within one week after revascularization. Among them, 10 patients' ipsilateral MCA-PI were less than 0.614, and another one's MCA- PI is higher than 0.614. Univariate analysis showed that the lower ipsilateral MCA-PI (0.448 ± 0.109 vs. 0.637 ± 0.124; P = 0.001) and higher Suzuki stage (P = 0.025) were linked to postoperative cerebral infarction. Multivariate analysis revealed that lower ipsilateral MCA-PI was an independent risk factor for predicting postoperative cerebral infarction (adjusted OR = 14.063; 95% CI = 6.265 ~ 37.308; P = 0.009).

Conclusions: A lower PI in the ipsilateral MCA may predict the cerebral infarction after combined revascularization surgery with high specificity. And combined revascularization appears to be safer for the moyamoya patients in early stages.

Keywords: Adult moyamoya disease; Infarction; PI; TCD.

Fig. 1

The flowchart showing patient inclusion and exclusion

Fig. 2

The relationship between MCA-PI and Suzuki stage. As is showed in the box diagram, the average MCA-PI of Suzuki stage I is 1.007, stage II is 0.703 ± 0.156, stage III is 0.603 ± 0.124, stage IV is 0.532 ± 0.099,and stage V is 0.466. The MCA-PI decreased with the advance of Suzuki staging, and there was a moderate negative correlation between them (r=-0.415, P < 0.001)

Fig. 3

The mRS score of patients with cerebral infarction after combined bypass surgery. The figure shows the mRS Scores of patients who developed cerebral infarction after bypass surgery at one week and three months of follow-up. Followed up 1 week, 2 patients were less than 2 points, 9 patients more than 2 points. Followed up 3 months after operation, 1 patient was 3 points, and 9 patients were less than 3 points. And 1 patient with severe disability caused by large area infarction had a mRS score of 5 at one week and three months after operation

Fig. 4

The ROC curve of ipsilateral MCA-PI in TCD. The area under the ipsilateral MCA-PI curve was 0.883 (AUC = 0.883; 95% CI = 0.784–0.983; P < 0.001). The best threshold was 0.467. At this time, the sensitivity of predicting postoperative complications was 72.7%, and the specificity was 91.7%

Fig. 5

Typical case 1. This a 40-year-old female patient, who was treated for half a year because of headache and weakness of the right limb. After admission, the patient was diagnosed as moyamoya disease by DSA examination, Suzuki stage III. TCD examination showed that the PSV, EDV and MFV of the left MCA were 198.9 cm/s, 112.1 cm/s and 141.0 cm/s. The PI was 0.615. Then the patient underwent left STA-MCA vascular anastomosis combined with EDMS. During the operation, the anastomotic stoma was full and good, and ICG fluorescein angiography showed that the bridging vessel was unobstructed. No new cerebral infarction was found in MRI after operation. The patient recovered well after operation and was discharged without complications related to neurological function

Fig. 6

Typical case 2. This is a 42-year-old female patient, who was treated for 7 months because of intermittent speech disorder and weakness of the right limb. After admission, the patient was diagnosed as moyamoya disease by DSA examination, Suzuki stage III. TCD examination showed that the PSV, EDV and MFV of the left MCA were 121.3 cm/s, 81.4 cm/s and 94.7 cm/s. The PI was 0.422. Then the patient also underwent left STA-MCA vascular anastomosis combined with EDMS. During the operation, the anastomotic stoma was full and good, and ICG fluorescein angiography showed that the bridging vessel was unobstructed. However, on the first day after the operation, motor aphasia and grade II right limb muscle strength were observed. Immediate examination of MRI showed that the DWI sequence found the new acute cerebral infarction appeared in the frontal lobe of the operative side. The patient’s condition was gradually stable after rehydration, an appropriate pressure increase, the addition of aspirin enteric-coated tablets, and the administration of edaravone and other secondary preventive drugs for stroke. On the fifth day after operation, the patient can simply answer; Right limb muscle strength grade IV; The right hand can make a fist and move against the palm, but the movement is slow, and the fine movements of the fingers have not recovered