Évaluation des pressions de remplissage ventriculaire gauche par échocardiographie-doppler

The evaluation of left ventricular (LV) filling pressures is crucial to identify a congestive heart failure in a patient presenting with an acute respiratory failure. This evaluation traditionally relies on the invasive measurement of the pulmonary artery occlusion pressure during right heart catheterization. Echocardiography Doppler is an unparalleled alternative technique to assess LV filling pressures, which also provides anatomical and functional information on the heart and great vessels. Pulsed wave Doppler of the mitral valve and pulmonary veins provides indices that are easy to measure and allow a semi-quantitative assessment of LV filling pressures. Their accuracy increases in the presence of a LV systolic dysfunction. New Doppler indices, which assess more specifically LV diastolic properties (Doppler Tissue Imaging of the mitral ring, color M-mode propagation velocity) can be combined to traditional Doppler parameters to more precisely assess LV filling pressures. In addition, echocardiography allows a comprehensive assessment of both the left and right ventricular function, the diagnosis of an underlying cardiopathy, or the identification of an acute condition of the heart or great vessels that precipitated the acute respiratory failure. Accordingly, echocardiography Doppler is a cornerstone in the evaluation of patients presenting to the intensive care unit with a respiratory failure and a high index of suspicion of pulmonary venous congestion. This imaging modality is particularly valuable for the evaluation of patients with a medical history of chronic respiratory failure and cardiac failure, to confirm or confidently rule out a cardiogenic pulmonary edema, or to identify a cardiac source of ventilator weaning failure.