Comparing Echocardiography and Right Heart Catheterization for Mortality Prediction in Pulmonary Hypertension

To identify right heart catheterization (RHC) and transthoracic echocardiography (TTE) predictors of mortality in pulmonary hypertension (PH).

Retrospective cohort at a tertiary care university hospital cardiac intensive care unit.

One hundred fifty-nine adults with PH admitted to a cardiac care unit who underwent RHC with a recorded transthoracic echocardiogram within 2 months.

None (retrospective study).

Data included demographic characteristics, RHC parameters, TTE variables, and 12-month mortality. Most admissions were for cardiac (60.4%) or pulmonary (34.6%) diagnoses; the mortality rate was 21% (34 of 159). Demographic characteristics and admitting diagnosis category were not associated with mortality. Integrated pulmonary-to-systemic hemodynamic ratios were strongly associated with mortality. Univariate predictors included a pulmonary artery systolic pressure systolic blood pressure ratio ≥ 0.50 (odds ratio [OR] = 3.47, p = 0.01), mean pulmonary artery pressure (mPAP)-mean arterial pressure (MAP) ratio ≥ 0.44 (OR = 3.89, p = 0.01), and pulmonary vascular resistance (PVR)-systemic vascular resistance (SVR) ≥ 0.12 (OR = 3.03, p = 0.002). MAP ≥ 84.3 mmHg (OR = 0.96, p = 0.003) and systemic perfusion pressure (SPP) (defined as MAP - right atrial pressure [RAP]) ≥ 75.2 mmHg were associated with lower mortality (OR = 0.96, p = 0.002). Significant multivariate predictors included MAP (OR = 0.96, p = 0.004), mPAP/MAP (OR = 10.12, p = 0.02), PVR/SVR (OR = 15.79, p = 0.001), and SPP (0.96, p = 0.002). Mortality was not associated with cardiac output (CO), stroke volume (SV), heart rate, RAP, or pulmonary artery pulsatility index (PAPi). Associations were independent of admitting diagnosis and hemodynamic PH subtype. Aside from qualitative right ventricle size and function (100% available), which was not predictive, TTE reporting was incomplete.

In critically ill patients with PH, mortality was best associated with systemic arterial pressure and integrated hemodynamic relationships (pulmonary-to-systemic ratios and SPP). These findings highlight the prognostic value of combining or integrating pulmonary and systemic hemodynamics. The absence of a significant association between CO and SV with outcome points toward the physiological importance of compensatory mechanisms to maintain right ventricle-pulmonary artery coupling, including ventricular interdependence.