Intraoperative Near-infrared Spectroscopy Findings Reflecting Cerebrovascular Autoregulation during Staged Angioplasty for Severe Carotid Artery Stenosis: A Case Report.

Cerebral hyperperfusion syndrome is a potentially life-threatening complication following carotid artery stenting, particularly in patients with impaired cerebrovascular autoregulation. Staged angioplasty has been proposed to reduce this risk by gradually restoring blood flow and promoting recovery of autoregulatory function. However, it remains unclear how autoregulation responds intraoperatively during each stage of staged angioplasty. We report a case of a 79-year-old man with progressive ischemic stroke caused by severe stenosis of the right internal carotid artery. Preoperative cerebral blood flow was reduced in the right hemisphere. Three months after stroke onset, first-stage percutaneous transluminal angioplasty was performed under near-infrared spectroscopy monitoring. Following balloon dilatation, the minimal lumen diameter increased from 0.4 mm to 1.0 mm, and a marked increase in regional cerebral oxygen saturation on the affected side prompted termination of further dilation. Postoperative imaging showed improved perfusion without signs of cerebral hyperperfusion syndrome. Nineteen days later, definitive carotid artery stenting was performed. Although the lumen diameter increased by 2.7 mm during the stenting procedure, there was no sustained increase in regional cerebral oxygen saturation, and no hyperperfusion or neurological symptoms developed. These contrasting intraoperative responses suggested that cerebral autoregulation was impaired before the first-stage percutaneous transluminal angioplasty procedure but had recovered by the time of the second. This case highlights the potential value of real-time near-infrared spectroscopy monitoring in assessing cerebral autoregulation and guiding intraoperative decision-making during staged angioplasty. Timely identification of hyperperfusion risk using this approach may improve the safety of carotid interventions, particularly in high-risk patients with compromised hemodynamic reserve.