Factors influencing the echocardiographic estimate of right ventricular systolic pressure in normal patients and clinically relevant ranges according to age

Abstract

Background: Previous studies have shown that in the absence of underlying cardiac pathology, the echocardiographic estimate of right ventricular systolic pressure (RVSP) increases progressively and normally with age. There are limited data in patients older than 60 years of age.

Objective: To define the ranges of RVSP according to age and to include more elderly patients than have previously been reported.

Methods: All patients undergoing echocardiography since May 26, 1999, at the Kingston Heart Clinic (Kingston, Ontario) have had their data entered into a locally designed cardiology database (CARDIOfile; Registered trademark, Kingston Heart Clinic). RVSP was calculated from the peak tricuspid regurgitant jet velocity (V) using the modified Bernoulli equation (RVSP = 4V2 + RAP), with the mean right atrial pressure (RAP) estimated to be 10 mmHg. Of the 22,628 patients who had undergone echocardiography, 10,905 had RVSP measured. All abnormal echocardiograms were excluded, leaving 1559 echocardiograms for analysis.

Results: Patient age ranged from 15 to 93 years. The mean age was 49 years. RVSP increased significantly only after the age of 50 years. The mean (+/- SD) RVSP for those younger than 50 years, 50 to 75 years, and older than 75 years of age was 27.3+/-5.7 mmHg, 30.2+/-7.6 mmHg and 34.8+/-8.7 mmHg, respectively (P<0.0001 among all age groups). The normal range (95% CI) of RVSP in those younger than 50 years, 50 to 75 years, and older than 75 years of age was 16 mmHg to 39 mmHg, 15 mmHg to 45 mmHg, and 17 mmHg to 52 mmHg, respectively. Multivariate analysis indicated that age, mitral diastolic early-to-late filling velocity ratio, ejection fraction, aortic size and early mitral filling velocity/ early diastolic mitral annular velocity were the only significant independent variables. There were significant changes in diastolic function with increasing age, which may have been responsible for the changes in RVSP.

Conclusions: RVSP remains stable in both men and women until the age of 50 years. Thereafter, RVSP increases progressively in a linear manner with age and is significantly higher in patients older than 75 years of age. The changes may relate to changes in diastolic function. These ranges should be taken into account when using echocardiogram-derived RVSP for the diagnosis of pulmonary hypertension in the absence of cardiovascular disease.

Figure 1)

Right ventricular systolic pressure (RVSP) in men and women with normal echocardiograms according to deciles of age. Using one-way ANOVA, P<0.0001. RVSP significantly increased only after the age of 49 years (Tukey-Kramer comparison test, P<0.001). Data are presented as mean ± SEM (n=1559)

Figure 2)

Right ventricular systolic pressure (RVSP) according to diastolic function. The first two groups are the current normal echocardiograms. The third group (early mitral filling velocity/early diastolic mitral annular velocity [E/e′] >14) are patients with the same echocardiographic findings but abnormal diastolic function. The final two groups are abnormal nonrestrictive diastolic function (AbNR) and abnormal restrictive diastolic function (AbR). Using one-way ANOVA, P<0.0001. Tukey-Kramer comparisons are P<0.001 for all except E/e′ 9 to 14 versus E/e′ >14 (P<0.05). Data are presented as mean ± SEM

Figure 3)

Right ventricular systolic pressure (RVSP) according to clinically relevant age groups in patients with normal echocardiograms. Using one-way ANOVA, P<0.0001. Using Tukey-Kramer comparisons, P<0.001. Data are presented as mean ± SEM (n=1559)