Importance of sampling both pulmonary veins in grading mitral regurgitation by transesophageal echocardiography

Pulmonary venous flow patterns have been used to assess severity of mitral regurgitation; however, the issue of which pulmonary veins to sample has not been determined. We performed pulsed wave Doppler transesophageal echocardiography of both the left and right upper pulmonary veins in 80 patients who had mitral regurgitation determined by independent transesophageal echocardiography color flow mapping. Pulmonary venous flow patterns, peak systolic and diastolic flow, and the presence of reversed systolic flow were compared between the left and right pulmonary veins for each grade of mitral regurgitation. Flow patterns were discordant in 20 (25%) of the 80 patients. Of the 43 patients with 4+ mitral regurgitation, there was discordant flow in 16 (37%) of the patients with mainly reversed systolic flow in the right upper vein, while there was blunted or normal systolic flow in the left upper vein. Of the 16 patients with discordant flows, 14 had eccentric jets, mainly anteromedial jets. We conclude that if discordant flow can occur in 25% of patients with mitral regurgitation and in 37% of patients with 4+ mitral regurgitation, then both pulmonary veins must be evaluated when assessing the severity of mitral regurgitation with pulsed wave Doppler transesophageal echocardiography.