Preembolization functional evaluation in brain arteriovenous malformations: the ability of superselective Amytal test to predict neurologic dysfunction before embolization.

PURPOSE To describe the incidence of neurologic dysfunction following embolization of supratentorial AVMs, and to correlate findings with results of preembolization Amytal tests. MATERIALS AND METHODS Data from 147 embolizations of supratentorial AVMs following Amytal tests in 30 awake patients were analyzed retrospectively. RESULTS Of five embolizations done after a positive Amytal test, two were followed by neurologic complications. Eighty-two embolizations done as single embolizations immediately after a negative Amytal test were associated with no neurologic complications. The remaining embolizations were parts of multiple series of embolizations, each beginning with an Amytal test and followed by a number of embolizations without catheter movement or repeat Amytal testing. Since any prior embolization in the series might reduce the sump effect of the AVM, embolic agent delivered later in the series could potentially reach functional brain tissue not fully tested by the Amytal test. Therefore, repeat embolizations (not immediately preceded by an Amytal test) were considered separately. In 60 repeat embolizations, six (10%) were associated with some neurologic complication. CONCLUSIONS Repeat Amytal testing might detect the loss of sump effect as the AVM is embolized. We conclude that use of data from superselective Amytal tests adds to the safety of AVM embolizations and that repeat Amytal testing potentially could be valuable when serial embolization of a vessel is planned.