Lievense A M, Bakker S L, Dippel D W, Taams M A, Koudstaal P J, Bogers A J
Department of Cardiothoracic Surgery, University Hospital, Rotterdam, The Netherlands.
J Cardiovasc Surg (Torino). 1998 Oct;39(5):613-7.
Comparison of the occurrence, intensity and rate of high-intensity transient signals (HITS), measured in both middle cerebral arteries by transcranial Doppler ultrasound (TCD) after mechanical or homograft aortic valve implantation.
TCD monitoring was performed by means of a pulsed Doppler ultrasound with two 2 MHz probes, stabilized on the head and directed at the middle cerebral artery.
Outdoor patients after aortic valve replacement in a university hospital.
The study cohort comprised a random transverse sample of patients and included 20 patients with a mechanical aortic valve and 20 with a homograft aortic valve. Comparisons were made with 20 admitted control patients.
No interventions.
No significant number of HITS were expected in the homograft group and a limited number in the mechanical valve group.
HITS were detected in more patients after implantation of a mechanical aortic valve prosthesis compared with a homograft aortic valve (16 versus 8, p=0.02). Nevertheless, more patients with a homograft aortic valve showed HITS than the control patients (8 versus 1, p=0.02). The mean number of HITS in the mechanical prosthesis group was higher than in the homograft group (3, range 0-18 versus 13, range 0-70, p<0.05). HITS in patients with mechanical prostheses had a higher amplitude than HITS in patients with homograft aortic valves (p<0.0001). Focal neurological deficit (FND) was diagnosed in 9 patients (mechanical prosthesis 6 versus homograft 3, ns).
HITS commonly occur both in patients with a mechanical aortic valve and in patients with a homograft aortic valve. HITS occur significantly less often, at a lower rate and with a lower intensity in patients with homograft aortic valve compared with patients with a mechanical aortic valve. Future studies should elucidate the nature and prognostic significance of HITS and their relationship with thromboembolic events.
比较经颅多普勒超声（TCD）在机械瓣或同种异体主动脉瓣植入术后双侧大脑中动脉测量的高强度瞬态信号（HITS）的发生率、强度和速率。
采用带有两个2MHz探头的脉冲多普勒超声进行TCD监测，探头固定在头部并指向大脑中动脉。
大学医院主动脉瓣置换术后的门诊患者。
研究队列包括患者的随机横向样本，其中20例为机械主动脉瓣患者，20例为同种异体主动脉瓣患者。与20例入院对照患者进行比较。
无干预措施。
预计同种异体瓣膜组中HITS数量无显著增加，机械瓣膜组中数量有限。
与同种异体主动脉瓣相比，机械主动脉瓣假体植入术后检测到HITS的患者更多（16例对8例，p = 0.02）。然而，同种异体主动脉瓣患者中出现HITS的人数比对照患者多（8例对1例，p = 0.02）。机械假体组中HITS的平均数量高于同种异体瓣膜组（3次，范围0 - 18次对13次，范围0 - 70次，p < 0.05）。机械假体患者的HITS幅度高于同种异体主动脉瓣患者的HITS（p < 0.0001）。9例患者被诊断为局灶性神经功能缺损（FND）（机械假体6例对同种异体3例，无显著性差异）。
机械主动脉瓣患者和同种异体主动脉瓣患者中均常见HITS。与机械主动脉瓣患者相比，同种异体主动脉瓣患者中HITS的发生率显著更低、速率更低且强度更低。未来的研究应阐明HITS的性质和预后意义及其与血栓栓塞事件的关系。
