Does blunted pulmonary venous flow relate to mitral regurgitation severity? a consecutive study of 580 patients

Previous studies reported that blunted pulmonary venous flow pattern indicates moderately severe mitral regurgitation (3+ MR). However, other studies demonstrated that the blunted pattern may be seen in patients with lesser degrees of mitral regurgitation. These studies used highly selective patients (pts). Therefore, the study of a large number of nonselective patients is needed. Methods: We prospectively studied pulmonary venous flow in 580 consecutive patients by transthoracic echocardiography. Right upper pulmonary venous flow was routinely examined. MR severity was determined by color Doppler mapping of regurgitant jets. Satisfactory pulmonary venous flow was recorded in 480 (83 %) pts. Peak systolic and diastolic pulmonary venous flow velocity were measured. A blunted flow pattern was present when the ratio of systolic to diastolic pulmonary venous flow velocity ́ 1. Results: Blunted flow pattern was detected in 103 pts (21%). Among them, 20 pts had no MR, 46 pts 1+ MR, 20 pts 2+ MR, 5 pts 3+ MR and 12 pts 4+ MR as determined by color Doppler mapping. In only a minority of patients (17%) was blunted pulmonary venous flow associated with significant MR (≥ 3+ MR). 51% of pts with blunted pulmonary venous flow had MR ≤ 2+ along with moderate to severe left ventricular dysfunction. 43% of pts had atrial fibrillation. Conclusions: Blunted pulmonary flow pattern is common during routine echo examination and is nonspecific for significant mitral regurgitation. Blunted pulmonary venous flow pattern should not be generally used as a marker of mitral regurgitant severity in clinical practice in the presence of left ventricular dysfunction or atrial fibrillation.