Trigemino-cardiac reflex and antecedent transient ischemic attacks

The trigemino-cardiac reflex (TCR) is a brainstem reflex that has gained enormous interest in recent years and was initially described by Schaller and coworkers as a centrally inducible reflex during skull-base surgery. In the meantime, parts of its functional consequences have been described. Here, we present a study that gives special reference to preventive factors of the TCR and investigates the hypothesis linking preceding transient ischemic attacks (TIAs) to the occurrence of TCR.

We retrospectively reviewed 338 consecutive patients with the histological diagnosis of a pituitary adenoma, who were operated on from 2000 to 2006 in the Neurosurgery department of the University of Gottingen in Germany. Depending on the occurrence of intraoperative TCR, patients were divided into TCR and non-TCR groups. In 19 of these patients (6%), we found the intraoperative occurrence of the TCR. The patient characteristics between the two subgroups were comparable.

There was a statistically significant difference between the subgroups of precedent TIA (TCR: 11% vs non-TCR: 4%) versus nonprecedent TIA (TCR: 89% vs non-TCR: 96%) regarding the intraoperative occurrence of the TCR (chi(2): p < 0.01).

A precedent TIA less than 6 weeks before operation represents a significant risk factor for subsequent intraoperative occurrence of the TCR. Our data may indicate, for the first time, the existence of an oxygen-conserving reflex not only in animals but also in humans. Its neuroprotective effect in the context of the TCR is discussed.