Changes in Transcranial Doppler Findings during Open Heart Surgery

Transcranial Doppler sonography is frequently used to monitor cerebral blood flow velocities during open heart surgery. There was little information about Doppler findings in patients with congenital heart diseases and valvular heart diseases.This study included 12 women and six men, with a mean age of 40.6 years. Two patients had ventricular septal defect, four were diagnosed as having atrial septal defect, and one had both defects. Eleven patients underwent surgical replacement of heart valves. Two underwent aortic valve replacements and two underwent surgery on both the aortic and mitral valves. In seven patients, the mitral valve was replaced because of mitral regurgitation. The maximum, mean, and minimum flow velocities of the left middle cerebral artery (MCA) were measured intraoperatively before and after replacement. In the patients with aortic insufficiency and ventricular septal defect, the mean and diastolic flow velocities were markedly reduced on Doppler recordings before valvular replacement. In the patients with aortic insufficiency, a bisferious pulse was found on the Doppler spectra. In contrast, in the patients with mitral regurgitation and atrial septal defect, the Doppler waveforms showed normal findings preoperatively. In the patients with raised intracranial pressure, a high value of PI and low diastolic flow velocities were found on the TCD spectra. The same findings were sometimes seen in the patients with aortic insufficiency or ventricular septal defect. In patients with mitral insufficiency or atrial septal defect, the Doppler spectra showed no change on the TCD records postoperatively. Spiky contours were detected by Doppler in the patients with valvular heart disease secondary to subacute endocarditis.It is concluded that TCD could provide an approximation of changes in cerebral blood flow velocity in patients with valvular heart disease and ventricular septal defect.