[Pulmonary venous flow in patients with chronic heart failure: feasibility and additional value compared to transmitral flow for non-invasive estimation of pulmonary wedge pressure].

BACKGROUND: In many cardiac conditions, Doppler of transmitral flow has been showed to be related to left ventricular filling pressure, but several factors may limit its practical value in estimating pulmonary wedge pressure in patients with chronic heart failure. Pulmonary venous velocities directly depend on the oscillations of left atrial pressure. Recent studies suggest that transthoracic Doppler of pulmonary venous flow provides a more accurate estimation of pulmonary wedge pressure. However the relative values of transmitral and pulmonary venous flow for assessing pulmonary wedge pressure in patients with chronic heart failure have not been fully classified until now. Accordingly, we performed this study to assess the feasibility of transthoracic Doppler of pulmonary venous flow in patients with chronic heart failure and to evaluate whether it provides additional information regarding pulmonary wedge pressure when compared with Doppler indices of transmitral flow. METHODS: Simultaneous Doppler echocardiographic examinations and right heart catheterizations were performed prospectively in 300 consecutive patients with chronic heart failure due to dilated cardiomyopathy. The correlations of mitral and pulmonary venous flow velocity variables, left atrial volumes, mitral regurgitation jet area and left ventricular ejection fraction with pulmonary artery wedge pressure were evaluated. RESULTS: A complete recording of transthoracic pulmonary venous flow including all components was obtained in 66% of patients, while only systolic and diastolic forward flow were recorded in 88% of patients. Several indices, derived from pulmonary venous flow, were correlated with pulmonary wedge pressure; the strongest correlation was between systolic fraction of peak velocities and pulmonary wedge pressure (r = -0.76). This value was similar to that obtained between deceleration rate (r = 0.78) and deceleration time (r = -0.67) of transmitral flow and pulmonary wedge pressure. A systolic fraction > 40% showed a greater positive predictive value than restrictive pattern of transmitral flow for identifying patients with pulmonary wedge pressure > 18 mmHg (95% vs 86% p < 0.05). This accuracy is confirmed also in patients who had a single peak of transmitral flow. CONCLUSIONS: Doppler of pulmonary venous flow can be performed in a high percentage of patients with chronic heart failure due to dilated cardiomyopathy. The indices derived from transthoracic pulmonary venous flow are strongly correlated with pulmonary wedge pressure and improve the noninvasive identification of patients with high pulmonary wedge pressure, even when transmitral flow pattern is difficult to be interpreted.