Measures of Right Ventricular Afterload Predict Exercise Pulmonary Hypertension beyond Mean Pulmonary Artery Pressure

Abstract

PurposeCurrent definitions of resting pulmonary hypertension (PH) are dependent on mean pulmonary artery pressure (mPAP>20mmHg) and pulmonary vascular resistance (PVR>3WU). Exercise is recommended as a provocative maneuver during right heart catheterization (RHC) to reveal abnormalities not evident at rest. The purpose of this analysis was to identify whether among patients with mPAP<20mmHg, other resting hemodynamic measurements may be sensitive in predicting latent exercise-associated PH.MethodsIn a cohort of patients with suspected PH referred for RHC with cycle ergometry resting pulmonary hemodynamic variables and measures of right ventricular (RV) afterload (total pulmonary resistance; TPR, PVR, PA compliance; PAC, and PA elastance; PEa) were explored in those with a mPAP<20mmHg. Latent Exercise PH was defined as ΔmPAP/Δcardiac output (CO)>3.2mmHg L/min−1. The sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of measures of RV afterload to predict exercise PH was evaluated.ResultsSixty-nine patents (49% female, 56±14years) referred for exercise RHC had a resting mPAP<20mmHg. TPR demonstrated a broad range of values with, 45% of patients having a TPR≥3WU. At rest and during exercise, compared to TPR<3 WU, patients with a TPR≥3WU had a lower CO, PAC, stroke volume, and higher PEa, wedge pressure pulse pressure and PVR. To identify latent exercise PH, TPR≥3WU had sensitivity 73%, specificity 68%, PPV 52% and NPV 84%. By contrast, the sens/spec/PPV/ NPV of PEa>0.5mmHg ml−1 was (5%, 100%, 100%, 69%), PAC<5ml mmHg−1 (64%, 62%, 44%, 22%), PVR>3WU (73%, 79%, 62%, 14%).ConclusionIn patients referred for exercise RHC with a resting mPAP<20mmHg, TPR≥3WU identified patients with more abnormal resting and exercise hemodynamics. The NPV of TPR ≥3WU was higher than that of other measures of RV afterload, but did not rule in, nor rule out, latent exercise PH with a high degree of confidence. Current definitions of resting pulmonary hypertension (PH) are dependent on mean pulmonary artery pressure (mPAP>20mmHg) and pulmonary vascular resistance (PVR>3WU). Exercise is recommended as a provocative maneuver during right heart catheterization (RHC) to reveal abnormalities not evident at rest. The purpose of this analysis was to identify whether among patients with mPAP<20mmHg, other resting hemodynamic measurements may be sensitive in predicting latent exercise-associated PH. In a cohort of patients with suspected PH referred for RHC with cycle ergometry resting pulmonary hemodynamic variables and measures of right ventricular (RV) afterload (total pulmonary resistance; TPR, PVR, PA compliance; PAC, and PA elastance; PEa) were explored in those with a mPAP<20mmHg. Latent Exercise PH was defined as ΔmPAP/Δcardiac output (CO)>3.2mmHg L/min−1. The sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of measures of RV afterload to predict exercise PH was evaluated. Sixty-nine patents (49% female, 56±14years) referred for exercise RHC had a resting mPAP<20mmHg. TPR demonstrated a broad range of values with, 45% of patients having a TPR≥3WU. At rest and during exercise, compared to TPR<3 WU, patients with a TPR≥3WU had a lower CO, PAC, stroke volume, and higher PEa, wedge pressure pulse pressure and PVR. To identify latent exercise PH, TPR≥3WU had sensitivity 73%, specificity 68%, PPV 52% and NPV 84%. By contrast, the sens/spec/PPV/ NPV of PEa>0.5mmHg ml−1 was (5%, 100%, 100%, 69%), PAC<5ml mmHg−1 (64%, 62%, 44%, 22%), PVR>3WU (73%, 79%, 62%, 14%). In patients referred for exercise RHC with a resting mPAP<20mmHg, TPR≥3WU identified patients with more abnormal resting and exercise hemodynamics. The NPV of TPR ≥3WU was higher than that of other measures of RV afterload, but did not rule in, nor rule out, latent exercise PH with a high degree of confidence.