Quantitative volumetry in patients with carotid disease - Effects of acetazolamide

The intracranial effects of acetazolamide on flow velocities can be monitor ed noninvasively by transcranial Doppler (TCD) sonography. Extracranial vol ume flow changes can now reliably be measured with color duplex M-mode syst ems. The authors tested the volumetric effects of acetazolamide in patients with high-grade unilateral carotid disease to quantify the amount of Row c hanges. Patients in group 1 had a high-grade > 70% internal carotid artery (ICA) stenosis, without collateral Row through the ophthalmic artery (OA). Patients with occluded ICA were included in group 2 (patent OA collateraliz ation) or group 3 (no OA collateralization) (n = 6 per group). In group 1, common carotid artery (CCA) volume flow in the stenotic (normal contralater al) side increased from 271 (388) ml/min by 52 (54)% with 1 g aceta- zolami de intravenously. Simultaneously, middle cerebral artery (MCA) flow velocit ies increased from 54 (56) cm/s by 47 (53)%. In group 2, extracranial volum e flow increased from 166 (444) ml/min by 19 (52)%. MCA Row velocities incr eased from 43 (65) cm/s by 13 (30)%. In group 3, volume flow increased from 159 (467) ml/min by 2 (46)%. Intracranial flow velocities rose from 49 (54 ) cm/s by 27 (41)%. Volume Row data showed the expected decline in patients with high-grade ICA stenosis and even more pronounced in patients with occ lusion of the vessel. Cerebral reserve capacity was less sufficient in pati ents with a patent OA, despite an additional supply of 30 ml/min, indicatin g a hemodynamically critical situation.