Dynamic Autoregulation Testing Does Not Indicate Changes of Cerebral Blood Flow Before and After Resection of Small-...

This study tested the hypothesis that dynamic cerebral autoregulation (AR) remains intact before and after the excision of human arteriovenous malformations (AVM). In 12 patients (six female and six male; mean age, 34 years) harboring cerebral AVMs (AVM group), and 15 patients (nine female/six male; mean age, 49 years) with deep-seated lesions (e.g., small frontobasal meningiomas) approached by transsylvian dissection (control group), we continuously assessed cerebral blood flow (CBF) using a thermo-diffusion technique, and mean arterial blood pressure (MABP). AR was estimated post-hoc using correlation-coefficient autoregulatory-index (Mx) analysis. Measurements were compared according to groups (AVM/control) and times (pre/post), referred to as conditions before and after AVM resection and transsylvian dissection, respectively. All values are given as mean ± SD. The correlation index Mx was without significant difference among the study groups, indicating unimpaired autoregulatory function. Intragroup comparisons related to AVM nidus size (small- (≤3 cm) and medium-sized (3-6 cm)) did not show significant influence on autoregulation. The study shows that in patients harboring small- and medium-sized AVMs, dynamic autoregulatory function as estimated by correlation-coefficient index analysis seems to be intact in the surrounding cerebrovascular bed perioperatively.