UCSF

Background

Pulmonary arterial capacitance (PAC) is a strong hemodynamic predictor of outcomes in patients with pulmonary hypertension (PH). Its value across subgroups of race/ethnicity, sex, and PH etiologies is unclear. We hypothesized that the association of PAC with outcomes would not vary across World Health Organization (WHO) PH group, race/ethnicity, or sex.

Methods

We performed a retrospective study in patients with PH diagnosed and managed at the Pulmonary Hypertension Comprehensive Care Center of a tertiary care hospital (n = 270). Demographic, diagnostic, treatment, and outcome data were extracted from the electronic medical record. Cox proportional hazards models were used to model time from right heart catheterization to event in univariate and multivariable models. Our primary outcome was all-cause mortality and our secondary outcome was PH hospitalization.

Results

The median age of the cohort was 56 years (±14.6), and 67% were female. In multivariable Cox models adjusted for significant covariates, decreased PAC remained independently and significantly associated with both all-cause mortality (p = 0.029) and hospitalization for PH (p = 0.010). No significant interactions were observed between PAC and race, sex, or WHO group. Hispanic patients exhibited a significant independent association with increased hospitalizations (p = 0.030), and there was a trend toward increased all-cause mortality in African Americans. WHO group 2 PH was associated with more frequent hospitalization (p = 0.004).

Conclusions

Decreased PAC is significantly associated with mortality and hospitalization in PH patients independent of race, sex, and PH subgroups. Further investigation is required to characterize the effects and determinants of racial disparities in PH.