Grading of pulmonary right-to-left shunt with transthoracic contrast echocardiography: does it predict the indication for embolotherapy?
BACKGROUND
Pulmonary arteriovenous malformations (PAVMs) are associated with severe neurologic complications in patients with hereditary hemorrhagic telangiectasia (HHT). Therefore, screening is warranted. Transthoracic contrast echocardiography (TTCE) can effectively detect a pulmonary right-to-left shunt (RLS).


OBJECTIVE
To determine prospectively the predictive value of TTCE grading to detect PAVMs on high-resolution CT (HRCT) scans of the chest and the indication for embolotherapy.


METHODS
Three hundred seventeen patients, referred for possible HHT, were screened for PAVMs. Patients who underwent both chest HRCT scanning and TTCE were included in the study (n = 281). For the purposes of this study we used a 3-point grading scale, and shunt grades 3 and 4 according to the classification model of Barzilai et al were combined. Embolotherapy was performed of all PAVMs judged large enough for treatment.


RESULTS
Echocardiographic criteria for a pulmonary RLS were present in 105 patients (41%) [mean (+/- SD) age, 43.7 +/- 15.7 years; female gender, 63%]. Chest HRCT scan findings were positive in 55 patients (52%) in this group. The positive predictive value of shunt grade for the presence of PAVMs on chest HRCT scans was 22.9% for grade 1 (n = 35), 34.8% for grade 2 (n = 23), and 83.0% for grade 3 (n = 47), respectively. None of the patients with PAVMs seen on chest HRCT scans and a TTCE grade 1 (n = 8) or 2 (n = 8) were candidates for embolotherapy. Of 39 patients with TTCE grade 3 and PAVMs seen on chest HRCT scans, 26 patients (67%) underwent embolotherapy.


CONCLUSIONS
An increased echocardiographic shunt grade correlates with an increased probability of PAVMs seen on chest HRCT scans. Only patients with a TTCE grade 3 displayed PAVMs on chest HRCT scans that were large enough for embolotherapy.
van Gent
Marco W F
MWF
Department of Cardiology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Post
Martijn C
MC
Department of Cardiology, St. Antonius Hospital, Nieuwegein, the Netherlands. Electronic address: m.post@antonius.net.
Snijder
Repke J
RJ
Department of Pulmonology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Swaans
Martin J
MJ
Department of Cardiology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Plokker
Herbert W M
HWM
Department of Cardiology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Westermann
Cornelis J J
CJJ
Department of Pulmonology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Overtoom
Tim T
TT
Department of Radiology, St. Antonius Hospital, Nieuwegein, the Netherlands.
Mager
Johannes J
JJ
Department of Pulmonology, St. Antonius Hospital, Nieuwegein, the Netherlands.
D000328:Adult; D001165:Arteriovenous Malformations / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000628:therapy*; D015897:Comorbidity; D003326:Coronary Circulation; D004452:Echocardiography / Q000379:methods; D004621:Embolization, Therapeutic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000002:abnormalities* / Q000000981:diagnostic imaging; D011667:Pulmonary Veins / Q000002:abnormalities* / Q000000981:diagnostic imaging; D011859:Radiography; D013683:Telangiectasia, Hereditary Hemorrhagic / Q000000981:diagnostic imaging / Q000453:epidemiology