2002 年 15 巻 3 号 p. 128-131
As the significance of the HITS count in patients undergoing heart valve replacement is still unknown, we compared the normal functioning of the St. Jude Medical (SJM) valve and the Advance The Standard (ATS) valve in the aortic position to evaluate any effects of differences in valve structure on the HITS count.
Fifty-seven patients after aortic valve replacement (40 with the SJM and 17 with the ATS) were examined by transcranial Doppler (TCD) monitoring for 15min. All the patients showed normal prosthetic valve function by echocardiography and cineradiography, and had no history of stroke or carotid stenosis. There were 42 males and 15 females with a mean age of 58.2 years. The mean duration after surgery was significantly longer in patients with the SJM (77.3 months) than in those with the ATS (39.3 months) .
The average HITS count was 1.55 per 15 min for the SJM and 0.59 per 15 min for the ATS, although the difference was not significant. These results suggest that the difference in the hinge structure and opening angle between the two valves may cause a slight difference in the HITS count. Therefore, in patients with valve replacement, the type of prosthesis should be considered when examining TCD.