[Estimate of lung capillary pressure and identification of the "pseudonormal" transmitral flow pattern in patients with severe systolic dysfunction of the left ventricle].

OBJECTIVES

Aim of this study was to investigate whether Doppler-derived transmitral flow velocity variables would allow a reliable estimate of pulmonary capillary wedge pressure in patients with left ventricular systolic dysfunction and normal mitral flow velocity pattern, and would then predict the presence of a "pseudonormal" transmitral flow velocity profile.

BACKGROUND

Abnormal relaxation and increased chamber stiffness have opposing effects on the left ventricular filling pattern. When both abnormalities are present at the same time, as often occurs in patients with systolic dysfunction, the mitral pattern may appear to be normal: in this case the ability of Doppler recording to assess diastolic function and predict left ventricular filling pressure may be significantly compromised.

METHOD

Pulmonary capillary wedge pressure (PWP) and Doppler transmitral flow velocity profile were simultaneously recorded in 70 postinfarction patients with ejection fraction < or = 35% and mitral flow velocity pattern apparently normal (E/A ratio between 1 and 2). Doppler traces were analyzed using a microcomputer-based digitizing system, and the following variables were measured: peak flow velocity in early diastole (E) and during atrial contraction (A), peak E/A wave velocity ratio and the deceleration time (Dec T) of early diastolic flow.

RESULTS

Mean E/A ratio was 1.3 +/- 0.2 and mean PWP was 17 +/- 7 mm Hg. Forty-two patients had a PWP < 20 mm Hg and the remaining 28 patients (40%) had PWP > or = 20 mm Hg. Peak E, peak A and E/A ratio were similar in the two groups, whereas Dec T was significantly (p < 0.001) lower in patients with > or = 20 mm Hg PWP (93 +/- 15 vs 146 +/- 19 msec). A very weak correlation was found between PWP and both E and A velocity (r = 0.14 and r = 0.09, respectively). Furthermore, no correlation was found between E/A ratio and PWP (r = 0.08). Conversely, a very close negative correlation was observed between Dec T of early filling and PWP (r = -0.96). Sensitivity and specificity of < or = 120 ms in Dec T in predicting > or = 20 mm Hg in PWP were 100% and 99%, respectively.

CONCLUSIONS

These data point out the relevant role of Doppler-derived deceleration time of early diastole in predicting left ventricular filling pressure. In patients with left ventricular systolic dysfunction an apparently normal diastolic filling pattern is often associated with elevated PWP. Through the estimate of increased PWP, early deceleration time seems to provide an important means of differentiating a real normal from a pseudonormal or masked abnormal filling pattern caused by increased left ventricular filling pressure.