Normal and Abnormal Relationships of Pulmonary Artery to Wedge Pressure During Exercise

Abstract

Background Resting right heart catheterization can assess both left heart filling and pulmonary artery (PA) pressures to identify and classify pulmonary hypertension. Although exercise may further elucidate hemodynamic abnormalities, current pulmonary hypertension classifications do not consider the expected interrelationship between PA and left heart filling pressures. This study explored the utility of this relationship to enhance the classification of exercise hemodynamic phenotypes in pulmonary hypertension. Methods and Results Data from 36 healthy individuals (55, 50–60 years, 50% male) and 85 consecutive patients (60, 49–71 years, 48% male) with dyspnea and/or suspected pulmonary hypertension of uncertain etiology were analyzed. Right heart catheterization was performed at rest and during semiupright submaximal cycling. To classify exercise phenotypes in patients, upper 95% CIs were identified from the healthy individuals for the change from rest to exercise in mean PA pressure over cardiac output (ΔmPAP/ΔCO ≤3.2 Wood units [WU]), pulmonary artery wedge pressure over CO (ΔPAWP/ΔCO ≤2 mm Hg/L per minute), and exercise PA pulse pressure over PAWP (PP/PAWP ≤2.5). Among patients with a ΔmPAP/ΔCO ≤3.2 WU, the majority (84%) demonstrated a ΔPAWP/ΔCO ≤2 mm Hg/L per minute, yet 23% demonstrated an exercise PP/PAWP >2.5. Among patients with a ΔmPAP/ΔCO >3.2 WU, 37% had an exercise PP/PAWP >2.5 split between ΔPAWP/ΔCO groups. Patients with normal hemodynamic classification declined from 52% at rest to 36% with exercise. Conclusions The addition of PP/PAWP to classify exercise hemodynamics uncovers previously unrecognized abnormal phenotypes within each ΔmPAP/ΔCO group. Our study refines abnormal exercise hemodynamic phenotypes based on an understanding of the interrelationship between PA and left heart filling pressures.

The role of exercise right heart catheterization to guide pulmonary hypertension therapy in older adults

“…Each exercise stage lasted for 5 min and TDCO was obtained in triplicate within 10% after the second minute of exercise. Selection of first/second work rates were based on the MRC breathlessness scale; scores of 4 or higher—15/25 watts (W), scores of 3 or less—25/40W for women and 40/70 W for men 6 …”

“…Procedures for hemodynamic analysis have been published by our lab 6,9,10 . Hemodynamics reported include heart rate (HR), systemic blood pressure, mean right atrial pressure (mRAP), systolic/diastolic/mean PAP (PASP/PADP/mPAP), TDCO, and mPAWP.…”

“…Our methods for resting supine RHC and exercise on a semi-upright ergometer have been reported previously. 6,9,10 Briefly, supine resting RHC was performed and pressures were sampled from the right atrium, right ventricle, and pulmonary artery. The balloon-tip was intermittently inflated for measurement of the PAWP.…”

“…6 Procedures for hemodynamic analysis have been published by our lab. 6,9,10 Hemodynamics reported include heart rate (HR), systemic blood pressure, mean right atrial pressure (mRAP), systolic/diastolic/mean PAP (PASP/PADP/mPAP), TDCO, and mPAWP. Supine resting hemodynamic classifications were reported as per the World Symposium for Pulmonary Hypertension (WSPH) definitions for PH (mPAP > 20 mmHg), PAH (mPAP > 20 mmHg, PAWP ≤ 15 mmHg, PVR ≥ 3 WU) and PH-LHD (mPAP >20 mmHg, PAWP > 15 mmHg).…”

“…1,2 Exercise stress during RHC may clarify the contributions of pulmonary vascular or left heart pathophysiology to PH. It has been demonstrated that, in select populations, resting PH diagnoses can be reclassified by exercise in approximately 40% of patients; [6][7][8] however, the effect on clinical management is less clear.…”