Transcranial Doppler application for risk assessment of stroke in patients with mechanical mitral valve


Kavian Ghandehari 1 , * , Zahra Izadi Mood 2


1 Associate Professor Department of Neurology, Southern Khorasan University of Medical Sciences, Birjand, Iran.

2 Practitioner, Southern Khorasan University of Medical Sciences, Birjand, Iran.


Hormozgan Medical Journal: 11 (3); e89551
Published Online: March 14, 2007
Article Type: Research Article
Received: April 04, 2006
Accepted: March 14, 2007




Introduction: Observing microembolic signals in brain vessels by transcranial
Doppler technology is a very common finding in patients with mechanical heart
valve. These signals are almost always clinically asymptomatic. The aim of this study
was assessment of transcranial Doppler in detecting probability of stroke in patients
with mechanical heart valve.
Methods: This descriptive study was carried out on 22 patients with St Jude
prosthetic mitral valve, in 2005. Prevalence and frequency of microembolic signals
were assessed during one hour and prothrombine time (PT) and International
Normalized Ratio (INR) of patients were evaluated during middle cerebral artery
monitoring. Correlation of cardioembolic stroke, severity of anticoagulant therapy
and atrial fibrillation was considered with Mean Frequency Scale of Microembolic
Signals (MFSMS). Data analysis was preformed by Mann-Whitny test and P<0.05
was considered statistically significant.
Results: Microembolic signals were detected on vessel monitoring in 77% of
cases. MFSMS in patients history of stroke was 14.25 after mitral valve
replacement and was 11.23 in other patients which is not a meaningful difference.
In cases with PT less than 22 seconds and INR more than 2.5, MFSMS of 6 and 16
patients were 12.92 and 10.97, respectively, which is not a significant difference.
MFSMS in 13 patients with atrial fibrillation and 9 patients without atrial
fibrillation were 11.88 and 10.94, which has no meaningful difference.
Conclusion: The recorded microembolic signals in brain vessels of patients with
mechanical heart valve are not fibrinous and the frequency of these signals does not
indicate the risk of stroke in these patients. So, transcranial Doppler is of no clinical
benefit in these patients and can not be a clue for severity of anticoagulant therapy.


Doppler Sonography Transcranial – Brain Infarction – Mitral Valve

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