Threshold of Pulmonary Hypertension Associated With Increased Mortality

Abstract

Background: There is increasing evidence that current thresholds for diagnosing pulmonary hypertension (PHT) underestimate the prognostic impact of PHT. Objectives: The aim of this study was to determine the prognostic impact of increasing pulmonary pressures within the National Echocardiography Database of Australia cohort (n ¼ 313,492). Methods: The distribution of estimated right ventricular systolic pressure (eRVSP) was examined in 157,842 men and women. All had data linkage to long-term survival during median follow-up of 4.2 years (interquartile range: 2.2 to 7.5 years). Results: The cohort comprised 74,405 men and 83,437 women 65.6 17.7 years of age. Overall, 17,955 (11.4%), 7,016 (4.4%), and 4,515 (2.9%) subjects had eRVSP levels indicative of mild (40 to 49 mm Hg), moderate (50 to 59 mm Hg), or severe ($60 mm Hg) PHT, respectively, assuming a right atrial pressure of 5 mm Hg. These subjects were more likely to die during long-term follow up (for severe PHT, adjusted hazard ratio: 9.73; 95% confidence interval: 8.60 to 11.0; p < 0.001). After adjustment for age, sex, and evidence of left heart disease, those subjects with eRVSP levels within the third (28.05 to 32.0 mm Hg; hazard ratio: 1.410; 95% confidence interval: 1.310 to 1.517) and fourth (32.05 to 38.83 mm Hg; hazard ratio: 1.979; 95% confidence interval: 1.853 to 2.114) quintiles had significantly higher mortality (p < 0.001) than those in the lowest quintile. Accordingly, a clear and consistent threshold of increased mortality (including 1- and 5-year actuarial mortality) around an eRVSP of 30.0 mm Hg was evident. Conclusions: In this large and unique cohort, the prognostic impact of clinically accepted levels of PHT was confirmed. Moreover, a distinctly lower threshold for increased risk for mortality (eRVSP >30.0 mm Hg) indicative of PHT was identified.