"The prevalence of HHT in North America is estimated to be one in 5,000, so the number of HHT patients in Canada is estimated at 6,750 and in USA 62,000," Dr. Khurshid Khan from University of Alberta, Edmonton, Canada, told Reuters Health in an email.
"TCD may become a good initial screening test to look for right-to-left shunt in a patient suspected to have HHT and especially in the follow-up of these patients with pulmonary AVMs (arteriovenous malformation) who undergo coiling."
Dr. Khan and colleagues compared TTCE and TCDc for detecting right-to-left shunt in 12 patients with HHT who also underwent CT pulmonary studies to determine the presence of pulmonary arteriovenous malformations.
TTCE identified right-to-left shunt in 10 of the 12 patients, including all four patients with pulmonary arteriovenous malformation on chest CT. TTCE was 100% sensitive and 25% specific in identifying pulmonary arteriovenous malformation.
TCDc showed a right-to-left shunt in nine of the 12 patients and identified all four patients with pulmonary AVM. This approach had 100% sensitivity and 37.5% specificity in detecting pulmonary AVM.
There was 92% agreement between TTCE and TCDc for detecting right-to-left shunt.
There were no immediate complications or new embolic adverse events within the 90 days after TCDc.
"TCD is easy to use because of its portability and instantaneous interpretation," Dr. Khan said.
"A direct cost comparison of echocardiogram and TCD has not been done," Dr. Khan added. "Therefore, it is difficult to compare the costs of the two procedures. However, given the nature of two procedures I suspect TCD to be cost-effective."
By Will Boggs, MD
Last Updated: 2011-05-03 10:30:21 -0400 (Reuters Health)
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