Background: The best revascularization strategy for moyamoya disease (MMD) remains unknown. Our aim was to characterize angiographic revascularization effects of a bilateral standardized revascularization approach, consisting of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and encephalomyosynangiosis (EMS) on one hemisphere and single EMS on the contralateral hemisphere of each patient, and to compare the effects of both revascularization strategies on cerebral hemodynamics. Methods: In 30 patients (18 females/12 males, age 8–63 years), standardized revascularization was performed. Digital subtraction angiography was performed preoperatively and at 7 days, 6 months and 12 months postoperatively. STA-MCA and EMS functions were graded I (poor), II (medium) or III (extensive) according to angiographic aspects. In 20 patients, cerebrovascular reserve capacity (CVRC) was assessed pre- and postoperatively (at 12 months) using xenon CT. Results: After 12 months, STA-MCA/EMS function was grade 1 in 40/40%, grade 2 in 27/26%, and grade 3 in 27/10% of hemispheres, respectively. Twelve months after surgery, single EMS showed grade I in 37%, grade II in 27%, and grade III in 20% of hemispheres. Combined revascularization improved CVRC significantly compared to preoperative measurement (preoperative: 16.5 ± 34.6% vs. postoperative: 60.8 ± 64.22%; p < 0.05). Single EMS did not improve CVRC significantly (preoperative: 21.8 ± 35.9% vs. postoperative: 34.8 ± 63.0%; p < 0.05). Conclusions: Combined and indirect revascularization may be successfully applied in a bilateral standardized approach. STA-MCA/EMS is superior to single EMS in restoring CVRC in adult MMD patients.

The acute neurological deficit present immediately after subarachnoid hemorrhage (SAH) correlates with overall outcome. Only limited data are available to quantify changes in cerebral perfusion in this acute phase, and this study sought to characterize those changes within the first 12 h post-SAH. Xenon contrast-enhanced CT scanning was performed in 17 patients (Hunt and Hess grade [HH] 1–3, n = 9; HH 4–5, n = 8) within 12 h after SAH. Cerebral blood flow (CBF) was analyzed in all cortical and central vascular regions of interest (ROI), as well as infratentorial ROI. Hemodynamic stress distribution (central/cortical ROI) was also calculated. Asymptomatic patients without perfusion deficits served as controls (n = 5), and Glasgow Outcome Scale score (GOS) was determined 3 months after the event. Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were within normal limits in all patients. CBF was significantly reduced in all patients with SAH (34 mL/100 g × min) compared to controls (67 mL/100 g × min; p < 0.001). Patients in better clinical condition (HH 1–3) presented with significantly less reduction of CBF (41 mL/100 g × min) compared to patients with more severe hemorrhage (HH 4–5: 24 mL/100 g × min; p < 0.001), and had better outcomes. Changes in perfusion were more pronounced in supratentorial than in infratentorial ROI. Hemodynamic stress distribution was most pronounced in patients with higher HH grade ( p < 0.05). The first 12 h after SAH are characterized by persistent, severe reduction of CBF, which in turn correlates with HH grade, but is independent of ICP or CPP. Acute peripheral vasospasm of the microvasculature, not detectable by conventional angiography, may account for this early phase of prolonged hypoperfusion.

Background and Purpose— Increased cortical microvascularization has been proposed to be a Moyamoya disease (MMD)–specific characteristic. It was the aim of our study to characterize the anatomic pattern and microhemodynamics of cortical microvascularization in MMD. Methods— Intraoperative indocyanine green videoangiography was performed in 16 adult MMD patients, 15 patients with atherosclerotic cerebrovascular disease (ACVD), and 10 control patients. Cortical microvascularization and microvascular hemodynamics were categorized and analyzed according to anatomic and functional indocyanine green angiographic aspects. Anatomic analysis included microvascular density, microvascular diameter, and microvascular surface per analyzed area. Microhemodynamic analysis included microvascular transit time, arterial microvascular transit time, and venous microvascular transit time. Results— Microvascular density and diameter were significantly increased in MMD patients (1.8±0.2 mm/mm ² and 0.24±0.03 mm, respectively) compared with those in ACVD patients (1.5±0.2 mm/mm ² and 0.20±0.02 mm, respectively) and controls (1.5±0.1 mm/mm ² and 0.19±0.03 mm, respectively). This resulted in significantly increased microvascular surface per analyzed area in MMD (67±13%) vs ACVD patients (47±7%) and controls (45±6%). Anatomic changes were paralleled by significantly increased microvascular and arterial microvascular transit times in MMD patients (11.55±3.50 and 6.79±2.96 seconds, respectively) compared with those in ACVD patients (8.13±1.78 and 4.34±1.30 seconds, respectively) and controls (8.04±2.16 and 4.50±1.87 seconds, respectively). Conclusion— Cortical microvascularization in MMD is characterized by significantly increased microvascular density and microvascular diameter, leading to increased microvascular surface. These anatomic alterations are accompanied by prolonged microvascular hemodynamics. These observations might represent an MMD-specific compensation mechanism for impaired cerebral blood flow.

Background: Moyamoya disease (MMD) is graded based on digital subtraction angiography (DSA) with limited clinical applications. The aim was to identify clinically relevant parameters that may be used to develop a novel MMD grading system. Methods: In 40 MMD patients bilateral revascularization surgery was performed. Clinical data including DSA, MRI and regional cerebral blood flow studies were assessed. χ² test corrected for dependency of measurements at the same subject and analysis of receiver operating characteristics were used to identify key parameters. Grading system included: DSA (stenosis/occlusion = 1 point; stenosis/occlusion + intracranial compensation = 2 points; stenosis/occlusion + intracranial compensation + extra-intracranial compensation = 3 points), MRI (no sign of ischemia = 0 points; signs of ischemia = 1 point) and cerebrovascular reserve capacity (CVRC > –5% = 0 points; CVRC < –5% = 2 points). MMD grade I referred to 1–2 points, grade II to 3–4 and grade III to 5–6 points. Results: DSA, MRI and CVRC were dependent factors associated with the occurrence of clinical symptoms. Receiver operating characteristics analysis indentified the grading system as superior to each single parameter in predicting clinical symptoms. Fourteen hemispheres were graded as mild (grade I), 35 as moderate (grade II) and 31 as severe (grade III); 21% of grade I, 63% of grade II and 93% of grade III hemispheres were clinically symptomatic. Conclusions: The proposed grading system allows to stratify for clinical symptomatology in MMD patients. Future studies will have to investigate its value for assessing clinical symptoms and treatment risks.

Morbidity and mortality of subarachnoid hemorrhage (SAH) are correlated with the severity of the patient's acute neurological deficit. This initial presentation has been attributed to cerebral hypoperfusion in the acute phase, and we investigated the impact of moderate hypothermia on the early changes in perfusion and metabolism following massive experimental SAH. SAH was induced in 61 anesthetized rats by rapid injection of 0.5 mL of arterial blood into the cisterna magna. In normothermia (NT), animals were kept at 37 degrees C, while in the primary hypothermia (pHT) group, temperature was lowered to 32 degrees C prior to SAH, and in the secondary hypothermia (sHT) group, cooling was started immediately after SAH. From 30 min prior to 180 min after SAH, Laser-Doppler-flowmetry (LDF) probes allowed online recording of cerebral blood flow (CBF) while parenchymal dialysate was collected by microdialysis probes within the frontoparietal cortex. In NT, the acute phase was characterized by impaired autoregulation and prolonged hypoperfusion. In pHT and sHT, autoregulation was preserved and acute hypoperfusion rapidly improved. SAH also caused a highly significant reduction in glucose in NT only. pHT significantly reduced accumulation of lactate, glutamate, and aspartate. Comparable trends were present for histidine, GABA, and taurine, while glutamine consumption was ameliorated. Early perfusion deficits caused by acute hypoperfusion and disruption of cerebral autoregulation can be ameliorated by hypothermia. Also, the acute phase of experimental SAH is characterized by glucose depletion, lactate accumulation, and release of excitatory amino acids, which can be influenced favorably by hypothermia.