The use of echo density to quantify pulmonary right-to-left shunt in transthoracic contrast echocardiography. (15th July 2020)

• Record Type: Journal Article
• Authors: Kroon, Steven; Van Thor, Mitch C J; Vorselaars, Veerle M M; Hosman, Anna E; Swaans, Martin J; Snijder, Repke J; Mager, Hans-Jurgen; Post, Marco C
• Is Part Of: European heart journal. Volume 22:Number 10(2021)
• Page Start: 1190
• Page End: 1196
• Publication Date: 2020-07-15
• Subjects: echocardiography -- telangiectasia -- hereditary haemorrhagic -- vascular malformations; Cardiovascular system -- Imaging -- Periodicals; Heart -- Imaging -- Periodicals; 616.10754
• DOI: 10.1093/ehjci/jeaa155
• Languages: English
• ISSNs: 2047-2404

Abstract

Abstract: Aims: Transthoracic contrast echocardiography (TTCE) is the recommended screening tool to detect pulmonary right-to-left shunt (RLS) caused by pulmonary arteriovenous malformations (PAVMs). We assessed a novel method to quantify the RLS using the change in echo density (ED) following contrast injection. Methods and results: An analysis of 437 consecutive patients [58% female, 47 years, interquartile range (IQR) 33–60] who underwent TTCE for the detection of a pulmonary RLS. Using ImageJ (National Institutes of Health), the change in ED was measured for each patient. This method was strongly correlated (Spearman's ρ = 0.89; P < 0.0001) with our standard method based on a four-point grading scale (no, mild, moderate, and severe RLS). In patients without a history of embolotherapy ( n = 334), a PAVM was detected with chest computed tomography (CT) in 66 and embolotherapy was judged possible in 35 of these patients. The median increase in ED was higher in the latter: +20.1% (IQR 12.3–34.0) compared to non-treatable PAVM +0.2% (IQR −0.2 to 1.1). The specificity to detect treatable PAVMs increased from 87% to 90% when using the novel method without affecting the sensitivity (of 100%). Using the optimal cut-off value of +4.5% increase in ED, 8/74 (11%) needed chest CT-scans—individuals with a moderate or severe RLS—were no longer required without missing any treatable PAVM. Conclusions: The use of ED quantification for pulmonary RLS is promising; resulting in a substantial decrease in the number of chest CT scans needed. However, this method and the threshold should be validated in an independent study population.