Prevalence of pulmonary hypertension in mitral regurgitation and its influence on outcomes

Abstract

Objective: Pulmonary hypertension (PHT) commonly coexists with significant mitral regurgitation (MR), but its prevalence and prognostic importance have not been well characterised. In a large cohort of adults with moderate or greater MR, we aimed to describe the prevalence and severity of PHT and assess its influence on outcomes.

Methods: In this retrospective study, we analysed the National Echocardiography Database of Australia (data from 2000 to 2019). Adults with an estimated right ventricular systolic pressure (eRVSP), left ventricular ejection fraction >50% and with moderate or greater MR were included (n=9683). These subjects were then categorised according to their eRVSP. The relationship between PHT severity and mortality outcomes was evaluated (median follow-up of 3.2 years, IQR 1.3-6.2 years).

Results: Subjects were aged 76±12 years, and 62.6% (6038) were women. Overall, 959 (9.9%) had no PHT, and 2952 (30.5%), 3167 (32.7%), 1588 (16.4%) and 1017 (10.5%) patients had borderline, mild, moderate and severe PHT, respectively. A 'typical left heart disease' phenotype was identified with worsening PHT, showing rising E:e', right and left atrial sizes increasing progressively, from no PHT to severe PHT (p<0.0001, for all). With increasing PHT severity, 1- and 5-year actuarial mortality increased from 8.5% and 33.0% to 39.7% and 79.8%, respectively (p<0.0001). Similarly, adjusted survival analysis showed the risk of long-term mortality progressively increased with higher eRVSP levels (adjusted HR 1.20-2.86, borderline to severe PHT, p<0.0001 for all). A mortality inflection was apparent at an eRVSP level >34.00 mm Hg (HR 1.27, CI 1.00-1.36).

Conclusions: In this large study, we report on the importance of PHT in patients with MR. Mortality increases as PHT becomes more severe from an eRVSP of 34 mm Hg onwards.

Keywords: heart valve diseases; hypertension, pulmonary; mitral valve insufficiency.

Figure 1

Study flow chart. This figure shows the analysis flow chart, performed in this study. eRVSP, estimated right ventricular systolic pressure; LVEF, left ventricular ejection fraction; MR, mitral regurgitation; MVR, mitral valve replacement; NEDA, National Echo Database Australia; PHT, pulmonary hypertension.

Figure 2

Frequency distribution of estimated right ventricular systolic pressure within the cohort. These data show the statistical distribution of estimated right ventricular systolic pressure (RVSP) levels.

Figure 3

Adjusted risk for all-cause mortality using Cox proportional hazards showing as estimated right ventricular systolic pressure (eRVSP) level increases based on clinical severity, risk of mortality increases in (A) the total cohort and (B) the cohort excluding patients with severe aortic stenosis and/or moderate or greater aortic regurgitation.