Temporal Patterns Of Pulmonary Vascular Loading During Exercise In Patients With Pre Versus Post Capillary Pulmonary Hypertension

Purpose In healthy humans, pulmonary artery pressures (PAP) increase modestly and equilibrate rapidly in response to constant intensity exercise. PAP increase markedly in pre- or post-capillary pulmonary hypertension (pre-cap or post-cap PH), but the time course is unclear. We studied pulse (PP) and diastolic (PADP) PAP as indices of pulsatile load and pulmonary vascular outflow pressure, respectively, and explored whether the magnitude and time course of their response to exercise differs in pre-cap or post-cap PH. Methods Patients underwent right heart catheterization with cycle-ergometry (25/40W, F/M), and were classified by their exercise hemodynamic responses: 1) Normal 2) pre-cap PH and 3) post-cap PH. PAP were recorded continuously and analyzed offline. Changes from Control, 2 min, and 7 min were examined. Results We studied 76 patients (47% F; 59±15 years); groups comprised 32 Normal, 22 pre-cap PH, and 22 post-cap PH. After exercise onset in the Normal group, PADP increased at 2 min (∆5±3mmHg). This increase was less than both pre-cap PH (∆9±4mmHg, p Conclusion During exercise, patients with pre-cap or post-cap PH demonstrate differences in both the magnitude and temporality of change in PAP. Despite constant work-rate, the pulmonary vascular load continues to increase in both pre-cap and post-cap PH.