Horn, E.

BACKGROUND: With pulmonary hypertension (PH), a pulmonary artery wedge pressure (PAWP)>15 mm Hg is used to diagnose left heart dysfunction, but some patients with adjudicated group 1 PH demonstrate PAWP>15 mm Hg. The primary objective of the study was to evaluate group 1 PH with high PAWP>15 mm Hg. METHODS: Patients with adjudicated group 1 PH from PVDOMICS between 2016 and 2019 were separated into high PAWP(>15 mm Hg) or normal PAWP and compared with adjudicated combined pre- and postcapillary (Cpc) PH related to heart failure with preserved ejection fraction (HFpEF). Participants underwent dynamic right heart catheterization and metabolomics. Findings were validated in 3 independent cohorts with adjudicated group 1 PH (validation cohorts 1 and 2 with exercise right heart catheterization and validation cohort 3 with resting right heart catheterization). RESULTS: Of 325 patients with group 1 PH (73% women, mean age 53.0±14.3 years), 15% (n=48) had high PAWP. Group 1 PH+high PAWP demonstrated greater obesity, left ventricular hypertrophy ( P <0.0002), left ventricular strain impairment ( P <0.0001), and decreased left ventricular compliance ( P <0.0001) compared with group 1 PH+normal PAWP, with changes comparable to Cpc-PH HFpEF (n=75). Compared with Cpc-PH HFpEF, left atrial function was better in group 1 PH+high PAWP with lower PAWP V wave, higher left atrial compliance, and left atrial ejection fraction ( P <0.0001 for all). Metabolomics demonstrated little difference between group 1 PH with high versus normal PAWP but large differences between group 1 PH+high PAWP versus Cpc-PH HFpEF (100 metabolites altered at false discovery rate P <0.05). Elevated PAWP was also observed in 18% of group 1 PH in the validation cohort 1 (n=402), with exercise PAWP response intermediately abnormal in group 1 PH+high PAWP relative to Cpc-PH HFpEF and group 1 PH+normal PAWP (interaction P <0.0001). Elevated PAWP was similarly observed in 22% and 19% of group 1 PH in validation cohorts 2 (n=55) and 3 (n=787), respectively. CONCLUSIONS: Approximately 1 in 5 adjudicated patients with group 1 PH has elevation in resting PAWP despite severe pulmonary vascular dysfunction and metabolomics consistent with traditionally defined group 1 PH. Despite resting PAWP elevation, these patients with group 1 PH were metabolomically and biologically distinct from Cpc PH HFpEF, with better left atrial function and diastolic reserve during exercise. These data emphasize the limitations of using resting PAWP alone to separate group 1 PH from HFpEF and call for development of more integrated clinical diagnostic criteria.

Abstract Rationale: Since the initial descriptions of pulmonary arterial hypertension (PAH), there has been a significant increase in PAH diagnoses among the geriatric population. Studies suggest that older PAH patients exhibit unique hemodynamic profiles and treatment responses. We hypothesized that patients ≥80 years old would have a unique clinical profile and worse outcomes. Methods: The Pulmonary Hypertension Association Registry (PHAR) is a prospective cohort of PAH and chronic thromboembolic pulmonary hypertension (CTEPH) patients new to care at a Pulmonary Hypertension Care Center in the US. Individuals &lt;18 years of age and those with CTEPH were excluded. Clinical data, quality of life measures, and functional capacity were recorded at time of enrollment and at follow up visits. Octogenarians were defined as those ≥80 years old and non-octogenarians as &lt;80 years old. Associations between age subgroups with the change in six-minute walk distance (6MWD), and worsened WHO functional class (WHO FC) at the next visit, and time to all-cause mortality were assessed using linear, binomial, and Cox regression, respectively. Results: The study sample included 87 PAH octogenarian patients and 2,583 non-octogenarian patients at enrollment. The Table shows that octogenarian PAH patients were of similar sex and race distribution as others, but had lower body mass index. Octogenarians were more likely to have idiopathic or CTD-related PAH, and differed from younger patients in terms of several sociodemographic variables. PAH treatment, WHO FC, quality of life, and hemodynamic also differed between the groups. Octogenarians had a lower change in 6MWD (-26m, 95%CI -52 – -2, p = 0.066) and worse WHO FC (2.0, 95%CI 1.1 – 3.8, p = 0.038) over time compared to other adults after adjustment for sex, BMI, PAH etiology, annual income, marital status, right atrial pressure, mean pulmonary artery pressure, and PAH treatment. Octogenarians had an increased risk of death compared to younger adults (hazard ratio 1.7, 95%CI 1.1 – 2.6, p = 0.022) after adjustment for covariates. Conclusions: While the eldest PAH patients may have some comparable features to younger patients, they are different in a variety of socioeconomic variables, disease type, hemodynamics, and number of PAH therapies. The eldest PAH patients demonstrate worse exercise and functional capacity with time and a 70% increased risk of death compared to younger patients. Further studies are needed to better characterize PAH in the elderly, as this may lead to more effective treatments and enhanced quality of life.