Color Doppler Splay: A Clue to the Presence of Significant Mitral Regurgitation

J Am Soc Echocardiogr. 2020 Oct;33(10):1212-1219.e1. doi: 10.1016/j.echo.2020.05.002. Epub 2020 Jul 22.


Background: The authors describe a previously unreported Doppler signal associated with mitral regurgitation (MR) as imaged using transthoracic echocardiography. Horizontal "splay" of the color Doppler signal along the atrial surface of the valve may indicate significant regurgitation when the MR jet otherwise appears benign.

Methods: Splay was defined as a nonphysiologic arc of color centered at the point at which the MR jet emerges into the left atrium. The authors present a series of 10 cases of clinically significant MR (moderately severe or severe as defined by transesophageal echocardiography) that were misclassified on transthoracic echocardiography as less than moderate. The splay signal was present on at least one standard transthoracic view in each case. To better characterize the splay signal, two groups were created from existing clinically driven transthoracic echocardiograms: 100 consecutive patients with severe MR and 100 with mild MR.

Results: Splay was present in the majority of severe MR cases (81%) regardless of vendor machine, ejection fraction, or MR etiology. Splay was particularly prevalent among patients with wall-hugging jets (28 of 30 [93%]). In patients with mild MR, splay was present less often (16%), on fewer frames per clip, and had smaller dimensions compared with severe MR. Color scale did not differ between subjects with and those without splay, but color gain was higher when splay was present (P = .04). Machine settings were further explored in a single subject with prominent splay: increasing transducer frequency reduced splay, while increasing color gain increased it.

Conclusions: The authors describe a new transthoracic echocardiographic sign of MR. Horizontal splay may be a clue to the presence of severe MR when the main body of the jet is out of the imaging plane. Splay is likely generated as a side-lobe artifact due to a high-flux regurgitant jet.

Keywords: Color Doppler splay; Echocardiography; Mitral regurgitation; Side-lobe artifact; Valvular disease.