Chest
Volume 132, Issue 1, July 2007, Pages 18-23
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ORIGINAL RESEARCH
PULMONARY VASCULAR DISEASE
Contrast Echocardiography Grading Predicts Pulmonary Arteriovenous Malformations on CT

https://doi.org/10.1378/chest.06-2356Get rights and content

Background:

Untreated pulmonary arteriovenous malformations (PAVMs) can present with life-threatening complications. Agitated saline solution transthoracic contrast echocardiography (TTCE) has been recommended as the screening test of choice for PAVMs in hereditary hemorrhagic telangiectasia (HHT). A TTCE grading system has been proposed but not validated. The aim of this study was to determine the positive predictive value (PPV) of TTCE grades for the presence of PAVMs on CT.

Methods:

A blinded retrospective review was conducted. All patients screened at the Toronto HHT Center (June 2002 to September 2004) with positive TTCE results were included. TTCE results were scored for delay (number of cardiac cycles) before appearance of microcavitations in the left atrium and graded for intensity of opacification. Grade 1 indicates minimal left ventricular opacification, grade 2 indicates moderate opacification, grade 3 indicates extensive opacification without outlining the endocardium, and grade 4 indicates extensive opacification with endocardial definition. Thoracic CT was performed in all patients, and results were scored as positive, negative, or indeterminate for PAVMs.

Results:

Of 155 patients screened for PAVMs, 104 had positive TTCE results. Complete data were available for 90 patients (87%). Mean age was 45 years; 62% were female. Seventeen percent of patients screened and 27% of patients with positive TTCE results had CT detectable PAVMs. There was a significant association between TTCE grade and presence of PAVMs on CT (p < 0.0001). The PPV of grades 1, 2, 3, and 4 were 0.02 (95% confidence interval, 0.00 to 0.06), 0.25 (95% confidence interval, 0.06 to 0.44), 0.56 (95% confidence interval, 0.23 to 0.88), and 1.0 (95% confidence interval, 1.0 to 1.0), respectively.

Conclusions:

Increased shunt grade predicts increased probability of PAVMs and may be used to guide decisions in the screening algorithm for PAVMs.

Section snippets

Materials and Methods

A retrospective review of charts, TTCE, and imaging was conducted. One hundred fifty-five consecutive newly referred patients to the Toronto HHT Center (adult clinic) were screened with TTCE between June 2002 and September 2004. All patients with positive TTCE results were included in this study and underwent thoracic CT scanning. This was the routine screening protocol followed for all patients referred to the HHT Center from 2002 to 2004. For each patient, the TTCE was reviewed for the

Results

Of 155 patients screened with TTCE, 104 patients (67%) had positive TTCE results. Mean patient age was 45 years (range, 16 to 75 years). The majority of patients screened were female (62%).

Of 104 patients with positive TTCE results, we had complete data for 90 patients (87%). In 14 patients, data were incomplete because the echocardiography tapes were lost and the studies could not be reviewed. Twenty-four of the 90 patients (27%) for whom we had both TTCE and CT data had CT detectable PAVMs.

Discussion

Patients with PAVMs are at significantly increased risk of complications including stroke, cerebral abscess, and massive pulmonary hemorrhage.3410 Early diagnosis of PAVMs is important so that preventative treatment with embolotherapy may be performed.3410 TTCE has been recommended as the screening test of choice for PAVMs, although the intensity of shunting on TTCE remains of uncertain clinical significance. We demonstrate here that TTCE shunt grading predicts the probability of PAVMs on CT.

Conclusions

We have demonstrated that TTCE shunt grading, on a four-point scale, is significantly associated with the probability of detecting PAVMs on CT. This provides additional information that is clinically relevant in guiding decision making about further diagnostic testing.

References (16)

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Financial support (M.E.F) was provided by the Nelson Arthur Hyland Foundation, St. Michael's Hospital Research Institute.

This study was conducted at St. Michael's Hospital.

The authors have no conflicts of interest to disclose.

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