Purpose: To determine the prevalence of pulmonary arteriovenous malformations (PAVMs) in Hereditary Hemorrhagic Telangiectasia (HHT) through a systematic screening program. To compare the various screening modalities for PAVMs.
Methods: All adults seen at the Toronto HHT Centre were screened for PAVMs. Screening methods included: history, physical examination, resting oximetry, diffusing capacity, chest radiograph, arterial blood gas on room air, oxygen shunt test and contrast echocardiography. Patients who had an abnormal screening test were recommended to undergo diagnostic imaging, including a CT scan of the chest and a pulmonary angiogram.
Results: 172 patients were screened, of whom 66% were female. The mean age was 41 years (range 15 to 87 years). Eighteen patients had previously been treated for PAVMs. Either chest radiograph, shunt test or contrast echocardiography was positive in 78/172 (45%). Diagnostic testing has been performed in 59/78 (76%). Patent PAVMs were diagnosed in 43/59 (73%). The minimum prevalence of PAVMs in our population of HHT patients is therefore 50/172 (29%). No additional cases were detected by history, physical examination, resting oximetry or diffusing capacity. In those with PAVMs, only 28/49 (57%) had exercise intolerance. Sensitivity and specificity of the oxygen shunt test were determined using local results and an ROC curve. Comparatively, contrast echocardiography was the most sensitive tool for diagnosing PAVMs.
Conclusion: PAVMs are frequent in people with HHT. Contrast echocardiography is a sensitive screening tool.
Clinical Implications: PAVMs, which are known to cause serious complications, are frequent in HHT. Patients with HHTshould therefore be screened for PAVMs. A sensitive screening program should include contrast echocardiography and a chest radiograph.
Supported by: Medical Research Council of Canada / Canadian Thoracic Society Fellowship (for Dr. M.E. Faughnan) and generous support of Nelson Arthur Hyland Foundation.
Marie E Faughnan, MD(*); J L Mandzia, BSc; K Nanthakumar, MD; R A Pugash, MD; J c Clark, MD; A T Graham, MD; D A Redelmeier, MD and R H Hyland, MD. Medicine, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Radiology and Diagnostic Imaging, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada and Medicine, Sunnybrook and Women's College HSC, Toronto, Ontario, Canada.
COPYRIGHT 1999 American College of Chest Physicians
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