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Indexed/Abstracted in: BIOSIS Previews, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,632
Online ISSN 1827-191X
Lievense A. M. 1,2, Bakker S. L. M. 2, Dippel D. W. J. 2, Taams M. A. 3, Koudstaal P. J. 2, Bogers A. J. J. C. 1
From the Departments of 1 Cardiothoracic Surgery, 2 Neurology and 3 Cardiology, University Hospital, Rotterdam, The Netherlands
Objective. 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.
Experimental design. 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.
Setting. Outdoor patients after aortic valve replacement in a university hospital.
Patients. 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.
Interventions. No interventions.
Measures. No significant number of HITS were expected in the homograft group and a limited number in the mechanical valve group.
Results. 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).
Conclusions. 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.