Pulmonary artery occlusion pressure estimation by transesophageal echocardiography: is simpler better?

Vignon and colleagues [1] prospectively assessed the ability of transesophageal echocardiography (TEE) to predict PAOP higher than 18 mmHg in mechanically ventilated patients with an inserted pulmonary artery catheter. In a first group, they analyzed simple Doppler variables derived from transmitral flow (TMF) and pulmonary venous flow (PVF) and performed the usual measurements and calculations (maximal velocity and velocity time integral of E (the maximal velocity of early diastolic TMF) and A (the maximal velocity of late diastolic TMF) wave, E/A ratio, E wave deceleration time (EDT), maximal velocity and velocity time integral of S (the maximal systolic PVF velocity) and D (the maximal diastolic PVF velocity) wave, S/D ratio, atrial filling fraction and systolic fraction of pulmonary venous flow (SFPVF)). TMF recording was inadequate for analysis in 10% of patients. The correlations between Doppler variables and pulmonary artery occlusion pressure (PAOP) were better in patients with depressed left ventricular (LV) systolic function than in those with normal LV systolic function. PAOP could be predicted by E/A >1.4, EDT >100 ms, atrial filling fraction >31% and SFPVF >44%, with similar sensitivity and specificity and acceptable positive and negative predictive values. In a second group these cutoff values were prospectively evaluated for prediction of PAOP higher than 18 mmHg. Additionally, they measured maximal early diastolic velocity of lateral mitral annulus by tissue Doppler (Ea) and color M-mode Doppler flow propagation velocity (Vp). An E/Ea ratio <8 and an E/Vp ratio <1.7 were predictive for PAOP >18 mmHg, but the use of these additional variables did not improve the correct estimation of PAOP.Elevated PAOP reflects an increase of LV end-diastolic pressure due to LV diastolic and/or systolic dysfunction/failure. PAOP less than 18 mmHg, if measured, supports criteria for the definition of acute respiratory distress syndrome and acute lung injury.Clinical an