Prognostic Value of Respiratory Variation in Right Atrial Pressure in Patients With Precapillary Pulmonary Hypertension

Abstract

Precapillary pulmonary hypertension (PH) is characterized by elevated mean pulmonary artery pressure from increased pulmonary vascular resistance (PVR). Lack of respiratory variation in right atrial pressure (RAP) can be viewed as a surrogate for severe PH and inability of the right ventricle (RV) to tolerate preload augmentation during inspiration. Is the lack of respiratory variation in RAP predictive of RV dysfunction and worse clinical outcomes in precapillary PH? We retrospectively reviewed RAP tracings of patients with precapillary PH who underwent right heart catheterization. Patients with respiratory variation in RAP (end expiratory - end inspiratory) ≤2 mmHg were considered to have effectively no meaningful variation in RAP. Lack of respiratory variation in RAP was associated with lower cardiac index by indirect Fick (2.34±0.09 vs. 2.76±0.1 L/min/m2, p=0.001), lower pulmonary artery saturation (60±1.02% vs 64±1.15%, p=0.007), higher PVR (8.9±0.44 vs 6.1±0.49 Wood units, p<0.0001), RV dysfunction on echocardiography (87.3% vs 38.8%, p<0.0001), higher proBNP (2163±2997 vs 633±402 ng/ml, p<0.0001), and more hospitalizations within 1 year for RV failure (65.4% vs 29.6%, p<0.0001). There was also a trend toward higher mortality at 1 year in patients with no respiratory variation in RAP (25.4% vs 11.1%, p=0.06). Lack of respiratory variation in RAP is associated with poor clinical outcomes, adverse hemodynamic parameters, and RV dysfunction in patients with precapillary PH. Larger studies are needed to further evaluate its utility in prognosis and potential risk stratification in patients with precapillary PH.