Transcranial Doppler study to assess intracranial arterial communication before aortic arch operation.

Background: The assessment of intracranial arterial communication is important to prevent a stroke from occurring during an aortic arch operation. Bilateral axillary artery perfusion was used with the left common carotid artery perfusion for selective cerebral perfusion. A preoperative left carotid artery compression test with measurement of the left middle cerebral artery (LMCA) flow was performed to determine how safe it was to interrupt the perfusion to the left common carotid artery.

Methods: Eighteen patients who were scheduled for an aortic arch operation underwent the test. Before surgery, the LMCA flow was detected using transcranial Doppler ultrasonography. During manual compression of the left carotid artery, the flow velocity of the LMCA was measured and expressed as a percent in comparison to the precompression value.

Results: During carotid artery compression, flow velocity of the LMCA was reduced to 56% +/- 36% (median, 63%; range, 0% to 100%) of the precompression value. The communication to the LMCA assessed with magnetic resonance angiography showed a weak relationship to the functional flow reserve of the LMCA based on a transcranial Doppler study. The results indicated that morphologic observation with magnetic resonance angiography did not reflect the dynamic nature of the intracranial collaterals.

Conclusions: A preoperative left carotid artery compression test with a measurement of the flow of the LMCA is useful to assess the feasibility of interrupting perfusion to the left carotid artery during aortic arch surgery with bilateral axillary artery perfusion.