Prognostic value of right atrial pressure to cardiac output slope in patients undergoing exercise right heart catheterization

BACKGROUND/AIMS: This study aimed to evaluate the prognostic value of the right atrial pressure to cardiac output relationship (RAP/CO-slope) from rest to end exercise in patients undergoing exercise right heart catheterization for suspected or confirmed pulmonary hypertension (PH). METHODS: The analysis used data from the retrospective arm of the Pulmonary Hemodynamics during Exercise Network (PEX NET), a multicenter collaboration involving 23 PH centers. Patients were included if resting and exercise measurements were obtained in the same body position and if RAP/CO-slopes were available. Cox proportional hazard models adjusted for age, sex, and hemoglobin were applied. Time dependent ROC curves were used to identify a prognostic cut off. RESULTS: A total of 856 patients were included (median age 59 years; 67% female), of whom 336 had PH. Over a median follow up of 6.5 years, 114 patients (13%) died. Higher RAP/CO-slopes were independently associated with increased mortality, even after adjusting for established resting and exercise hemodynamics (hazard ratio 1.08, 95%CI: 1.03-1.13, p < 0.001). Among patients with manifest PH at rest, a RAP/CO-slope ≥1.0 mmHg·min·L⁻¹ was linked to a 2.2 fold higher mortality risk (hazard ratio: 2.20; 95% CI: 1.1-4.5; p = 0.032) compared with slopes <1.0 mmHg·min·L⁻¹. In a multivariable model including NT proBNP, 6 minute walking distance, and WHO functional class, the RAP/CO-slope remained the strongest predictor of mortality. CONCLUSION: The RAP/CO-slope is a strong, independent prognostic marker across a spectrum of RV afterload stress. A RAP/CO slope ≥1 mmHg·min·L⁻¹ was identified as particularly predictive in manifest PH.