Dynamics of cerebral perfusion deficits after aneurysmal SAH - predictive value of early MTT for subsequent MTT deterioration

The pathogenesis of poor functional outcome after aneurysmal subarachnoid hemorrhage (aSAH) is not fully understood. Microcirculatory dysfunction, which can be indirectly measured by CT perfusion (CTP), is assumed to play a central role. We evaluated the predictive value of early changes in microcirculation for secondary critical perfusion changes.

Out of 351 consecutive aSAH patients, 166 patients with ≥1 CTP within 72h of ictus (early CTP) and ≥3 CTPs in total were included in the retrospective analysis (53.2±12.4years of age). Receiver-operating-characteristic (ROC) analysis was performed to identify the mean transit time (MTT) threshold in early CTP with the highest sensitivity and specificity for predicting secondary critical perfusion changes >72h after ictus. The odds ratio was calculated and the threshold for the highest odds ratio was determined.

Secondary critical perfusion changes were observed in 67/166 patients (40.4%). An early MTT 1.3 times the mean normal MTT could predict those changes with an odds ratio of 2.67 (sensitivity 67.2%, specificity 56.6%). Shifting the threshold to 1.26 times the mean normal MTT resulted in an odds ratio of 3.56 (sensitivity 79.1%, specificity 48.5%).

Early MTT is predictive of secondary critical perfusion changes, which could have applications for neuromonitoring and treatment.