Abstract 10333: Responsiveness to Pulmonary Vasodilator Testing has no Impact on Long-Term Success of Medical Therapy for Advanced Idiopathic Pulmonary Arterial Hypertension
Objective: Vasoconstriction is a key element in the pathology of idiopathic pulmonary arterial hypertension (IPAH) but, with progression of the disease, morphologic alterations reduce the vasodilator responsiveness. Although at the time of diagnosis more than 75% of IPAH patients show no relevant response to pulmonary vasodilator testing (PVT), the routine assessment of pulmonary vascular reagibility is still recommended. Having a large number of non-responders to PVT who profited from long-term pulmonary vasodilator therapy, we assessed the impact of responsiveness to acute PVT on IPAH patients' long-term outcome.
Methods: Patients with advanced IPAH at the time of diagnosis (WHO/NYHA class > II), who were referred for medical therapy and/or transplantation (Tx) since 1997 were included into the study, starting with the time when they underwent heart catheterization with assessment of responsiveness to PVT. We investigated the impact of responsiveness to PVT on their further outcome with a stepwise therapeutic regimen including bosentan, sildenafil and iloprost, aiming to answer the question whether Tx-free survival for non-responders to PVT is indeed relevantly lower than for responders ?
Results: Over 10% of pulmonary vascular resistance (PVR) decrease and cardiac index increase during PVT with prostacyclin or iloprost occurred in 32 (47%) of 68 studied patients (responders). However, 30 of 32 responders showed only slight to moderate responsiveness and the prevalence of good responders (≥ 50% PVR decrease) among all studied patients was only 3%. After testing, patients underwent a stepwise regimen for reduction of pulmonary vascular resistance starting with bosentan, sildenafil or iloprost inhalation as monotherapy and culminating with intravenous iloprost-based combination therapy. The probability of 5 year Tx-free survival calculated from onset of this stepwise therapy reached 59.6 ± 9.3% in the responder group and 58.5 ± 8.8% in the non-responder group (p = 0.46).
Conclusions: The responsiveness to PVT in IPAH patients with functional NYHA class > II had no impact on the long-term success of medical therapy with iloprost ± bosentan and/or sildenafil. The results of invasive PVT appeared not helpful for therapeutic decisions in these patients.
- © 2010 by American Heart Association, Inc.