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Echocardiography of the pulmonary circulation and right ventricular function: exploring the physiologic spectrum in 1,480 normal subjects.

BACKGROUND
Although transthoracic echocardiography (TTE) is an excellent noninvasive screening test for pulmonary hypertension, the physiologic range of Doppler echocardiography-derived pulmonary pressures remains not completely investigated. The aim of the present study was, therefore, to explore the full spectrum of pulmonary pressures and right ventricular (RV) functional indexes by TTE in healthy subjects and to investigate clinical and echocardiographic correlates.


METHODS
A random sample of 1,480 healthy individuals (mean age, 36.1 ± 15.5 years; range, 20-80 years; 905 men) underwent a comprehensive TTE. Pulmonary artery systolic pressure (PASP), mean pressure, and pulmonary vascular resistance were estimated by standard Doppler echocardiography formulas. In addition, RV diastolic (Doppler transtricuspid inflow measurements) and systolic indexes (RV fractional area change, RV tissue Doppler peak systolic velocity, tricuspid annular plane systolic excursion) were calculated.


RESULTS
PASP and mean pulmonary artery pressure values were significantly higher in subjects aged > 50 years and in those with a BMI > 30 kg/m2. In particular, a PASP > 40 mm Hg was found in 118 subjects (8%) of those aged > 50 years and in 103 (7%) of those with a BMI > 30 kg/m2. No differences by age were registered in RV systolic indexes and in pulmonary vascular resistances. On multivariate analysis, in the overall study population, age, BMI, mitral E/e' ratio, and left ventricular stroke volume were the only independent predictors of PASP.


CONCLUSIONS
This study delineates an estimate of pulmonary hemodynamics in a wide age range cohort of healthy subjects. Pulmonary pressures increased with age and BMI, as expected.