Eika Hamano

Correlation between reduction in microvascular transit time after superficial temporal artery–middle cerebral artery bypass surgery for moyamoya disease and the development of postoperative hyperperfusion syndrome

OBJECTIVE Hyperperfusion syndrome (HPS) is a notable complication that causes various neurological symptoms after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery for moyamoya disease (MMD). The authors used intraoperative indocyanine green (ICG) videoangiography to measure the change in microvascular transit time (MVTT) after bypass surgery. An analysis was then conducted to identify the correlation between change in MVTT and presence of postoperative HPS. METHODS This study included 105 hemispheres of 81 patients with MMD who underwent STA-MCA single bypass surgery between January 2010 and January 2015. Intraoperative ICG videoangiography was performed before and after bypass surgery. The MVTT was calculated from the ICG time intensity curve recorded in the pial arterioles and venules. Multivariate logistic regression analysis was conducted to test the effect of multiple variables, including the change in MVTT after bypass surgery, on postoperative HPS. RESULTS Postoperative HPS developed in 28 (26.7%) of the 105 hemispheres operated on. MVTT was reduced significantly after bypass surgery (prebypass 5.34 ± 2.00 sec vs postbypass 4.12 ± 1.60 sec; p < 0.001). The difference between prebypass and postbypass MVTT values, defined as ΔMVTT, was significantly greater in the HPS group than in the non-HPS group (2.55 ± 2.66 sec vs 0.75 ± 1.78 sec; p < 0.001). Receiver operating characteristic curve analysis revealed that the optimal cutoff point of ΔMVTT was 2.6 seconds (sensitivity 46.4% and specificity 85.7% as a predictor of postoperative HPS). A ΔMVTT > 2.6 seconds was an independent predictor of HPS in multivariate analysis (hazard ratio 4.88, 95% CI 1.76-13.57; p = 0.002). CONCLUSIONS MVTT in patients with MMD was reduced significantly after bypass surgery. Patients with a ΔMVTT > 2.6 seconds tended to develop postoperative HPS. Because ΔMVTT can be easily measured during surgery, it is a useful diagnostic tool for identifying patients at high risk for HPS after STA-MCA bypass surgery for MMD.

Neurosurgical Management and Outcomes of Cerebrovascular Disease in Pediatric Patients with Heart Disease

Antithrombotic treatment has substantial risks, even in pediatric patients. We retrospectively evaluated the management and outcomes of consecutive pediatric patients who underwent neurosurgical treatment for cerebrovascular disease with cardiovascular disease between 1998 and 2017. Patients were divided into patients with comorbid cardiovascular disease (group I); and patients with cardiovascular disease as a primary disease of intracranial complication, without (group IIa) or with (group IIb) extracorporeal circulations. Postoperative resumption of antithrombotic agents was generally initiated within 48 h. Our study included 26 patients; five were categorized as group I, 15 as group IIa, and six as group IIb. All intracranial diseases in groups IIa and IIb were exclusively hemorrhagic. Preoperative anticoagulation therapy was used in one patient (20%) in group I, 13 patients (86.7%) in group IIa, and six patients (100%) in group IIb. Postoperative intracranial hemorrhagic events were observed in one patient (20%) in group I, three patients (20%) in group IIa, and four patients (66.7%) in group IIb. Re-operations were conducted in two (13.3%) and three patients (50%) in groups IIa and IIb, respectively. Death occurred in five (33.3%) and four patients (66.7%) in groups IIa and IIb, respectively. The remaining two patients in group IIb returned to candidate status for implantation. Emergent surgery for patients with intracranial hemorrhage associated with cardiovascular disease has a high risk of postoperative hemorrhagic events and high rate of re-operations with poor vital outcomes, especially in patients with extracorporeal circulations. We should consider maximum neurosurgical treatment achievable with optimal management of antithrombotic treatment.

Response to “Letter on ‘Management of pregnancy complicated with intracranial arteriovenous malformation’”

We appreciate the interest and comments of Dr. Kumari and Dr. Bhatia on our article regarding the management of pregnancies complicated by intracranial arteriovenous malformation (iAVM). In the 36 cases we reported, 15 cases had no residual iAVM at conception, so these cases were not at risk for rebleeding. Regarding the angioarchitecture for the iAVM in the other 21 cases, the location of the iAVM was superficial in 13 and deep in 8 cases. The size of the iAVMs was small (<3 cm) in 15, medium (3~6 cm) in 4 and large (>6 cm) in 2 cases. One case had an associated arteriovenous fistula, and no cases had venous stenosis. In our case series, we did not perform endovascular embolism for the treatment of ruptured iAVM. If the nidus was in an operable position, and hemorrhage occurred in the first or second trimester, the nidus was removed, and the pregnancy continued. We decided on this mode of management after multidisciplinary team review because our surgical results for iAVMs are good. Our hospital is a specialized center for cerebrovascular diseases, and we operate a 24/7 service for cerebrovascular surgery. Surgical treatment made vaginal delivery possible in the index pregnancy in nearly all cases without fear of a rebleed. In one case, the nidus was located in the brain stem and was initially inoperable, and the patient had a hemorrhage in the second trimester. To reduce the risk of further bleeding during pregnancy, which could have been fatal for the mother, delivery was induced at 17 weeks, and subsequently, gamma knife radiosurgery was performed. We agree with Dr. Kumari et al. that endovascular embolism has a promising role in palliative as well as primary treatment in the management of iAVMs, including those diagnosed in association with pregnancy. We do use this technique if there are specific indications. As mentioned before, there are no consensus guidelines for the management of iAVMs in pregnancy, and therefore, the best management is likely to be that with which the center has the most expertise. As a result, such management will vary from center to center.

Management of pregnancy complicated with intracranial arteriovenous malformation

To clarify the perinatal outcomes in pregnancy complicated with intracranial arteriovenous malformation (i‐AVM).