Transcranial Doppler monitoring during percutaneous transluminal aortic valvuloplasty

Cerebral blood flow was studied in 12 elderly patients with severe calcific aortic stenosis by means of transcranial Doppler sonography (TCD) during percutaneous transluminal aortic valvuloplasty (PTAV). In 8 of these 12 patients duplex sonography revealed a stenosis of the internal carotid artery (ICA) exceeding 50%. Frequency spectra of 10 patients showed a satisfactory quality and were analyzed. In 7 subjects balloon inflation was well tolerated and systolic blood pressure did not drop below 75 mmHg. In these patients, whether they had a stenosis of the ICA or not, blood flow velocity in the middle cerebral artery (MCA) did not decrease to a critical level. The authors defined "critical" as a reduction of mean blood flow velocity in the MCA exceeding 50% or a decrease below 35 cm/sec. Three patients showed a rapid decrease of systolic aortic pressure below 75 mmHg. In these subjects mean blood flow velocity in the MCA dropped to levels below 35 cm/sec. Deflation and retraction of the balloon resulted in a rapid increase of systemic blood pressure and flow velocity in the MCA. This report demonstrates TCD to be a useful monitoring method of determining residual perfusion in patients with aortic stenosis during PTAV.