Objective: Temporary balloon occlusion (TBO) is the principal means to evaluate cerebrovascular reserve before carotid sacrifice (CS). Despite TBO, the incidence of ischemic events after CS remains a substantive problem. We hypothesized that differential alteration of systemic hemodynamic parameters during TBO could serve as measures of potential cerebral autoregulation-induced systemic compensatory responses. These responses indicate compromised cerebrovascular reserve, thereby predicting ischemic events after CS.
Methods: We conducted a retrospective review of patients who underwent TBO and CS from 1995 to the present. Demographics, neuroimaging including angiography, and hemodynamic parameters at baseline, during TBO, and after CS were reviewed. The incidence of ischemia after CS was evaluated. Multivariable logistic regression models were used to predict the risk of ischemic events.
Results: Of 139 patients who underwent TBO, 128 (92.1%) passed according to established criteria. Of 65 patients who underwent CS, 11 patients had unchanged or decreased systolic blood pressure (SBP), whereas 54 patients had a spontaneous elevation of SBP during TBO. Only patients with a spontaneous elevation of SBP experienced ischemic events after CS (11 patients, 16.9%). All ischemic events occurred within 4 days. Men and individuals older than age 50 were at higher risk of ischemic complications, despite demonstration of tolerance to TBO.
Conclusion: SBP changes during TBO are manifestations of systemic response to an adequate or a compromised cerebrovascular reserve. These systemic responses are crucial to predict outcome after CS. We strongly recommend adjunctive tests in the instances of spontaneous elevation of SBP during TBO, particularly in men and the elderly.