Original article
Assessment of Stress-induced Pulmonary Interstitial Edema by Chest Ultrasound During Exercise Echocardiography and its Correlation with Left Ventricular Function

https://doi.org/10.1016/j.echo.2005.11.013Get rights and content

Ultrasound lung comet images (ULC) are useful for the noninvasive assessment of extravascular lung water (EVLW). We investigated the modification of EVLW, its relation to indices of left ventricular systolic and diastolic function, and noninvasively determined pulmonary capillary wedge pressure (PCWP) (PCWP = 1.24 ratio of early diastolic mitral inflow velocity to early diastolic velocity of the mitral annulus [E/Em] + 1.9) at rest and its variation during exercise echocardiography. A total of 72 patients (mean age 66.4 ± 8.4 years) with mean ejection fraction of 41.2 ± 14.4% underwent symptoms-limited exercise echocardiography. The sum of the ULC yielded a score of EVLW. The ULC increased significantly from baseline to postexercise (5.9 ± 14.9 vs 11 ± 20.7, P = .0001). Positive linear correlations were found between baseline ULC score and baseline ejection fraction (r = −0.37, P = .002), systolic pulmonary artery pressure (r = 0.69, P = .0001), E/Em (r = 0.70, P = .0001), and estimated PCWP (r = 0.69, P = .0001). The variation between postexercise and baseline ULC score correlated significantly with the variation between peak stress and rest PCWP (r = 0.62, P = .0001), systolic pulmonary artery pressure (r = 0.44, P = .0001), wall-motion score index (r = 0.30, P = .01), and peak stress E/Em (r = 0.71, P = .0001), whereas no significant correlations were found between variations of ULC score and ejection fraction. This study shows that ULC represents a simple way to assess the presence of excess EVLW. Increased EVLW is associated with estimated PCWP and indices of left ventricular systolic and diastolic dysfunction. The additional exercise-induced increase of PCWP, the worsening of left ventricular diastolic function, and extensive wall-motion abnormalities correlate with variations of EVLW.

Section snippets

Patient Population

A total of 72 patients (mean age 66.4 ± 8.4 years; 23 women and 49 men), 53 with systolic LV dysfunction (ejection fraction [EF] < 40%) and 19 with normal LV function, were included in the study. The mean EF was 41.2 ± 14.4%. The current drug therapy was not stopped before the exercise test. Exclusion criteria were organic mitral valve diseases, aortic valve diseases, hypertrophic cardiomyopathy, and pulmonary diseases. All patients gave written informed consent.

Echocardiographic Study

All patients underwent

Results

The baseline clinical and echocardiographic characteristics of patients are reported in Table. The feasibility of the chest ultrasound examination for the diagnosis of presence of pulmonary edema was 100% and the time needed for echocardiographic lung examination was less than 5 minutes in all patients both at rest and in the postexercise phase.

The mean maximum rate–pressure product was 18,279 ± 4838. Comparing the values obtained at rest with those calculated at peak of the stress we found an

Discussion

This study shows that ULC represent a useful and simple way to assess the presence of excess of EVLW and its variation during exercise. Increased EVLW is associated with estimated PCWP and indices of LV systolic and diastolic dysfunction. Moreover, the additional exercise-induced increase of PCWP, worsening of LV diastolic function, and induced extensive wall-motion abnormalities correlate with variations of EVLW.

The ULC appear when there is a marked difference in acoustic impedance between an

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