Abstract 2305: Pulmonary Vascular Reactivity And Prognosis In Patients With Chronic Thromboembolic Pulmonary Hypertension
Hemodynamic responder status defined as an acute decrease of mean pulmonary arterial pressure (mPAP)>10mmHg and below 40mmHg is associated with improved outcome in patients (pts) with pulmonary arterial hypertension (PAH). Pulmonary vascular reactivity to nitric oxide (NO) is controversial in chronic thromboembolic pulmonary hypertension (CTEPH). We speculated that the magnitude of the acute decrease in mean pulmonary artery pressure (mPAP) after exposure to NO might reflect the degree of small vessel disease in CTEPH and thus, affect long-term outcome.
Methods: Right heart catheterization was performed in 62 (55 Â ± 15 years, 32 female) pts with major-vessel CTEPH, at baseline and during inhalation of 40ppm NO. Within 25Â±15 days patients underwent pulmonary endarterectomy (PEA). Pts were followed for 11.3Â±26 months. Predictors of survival were analyzed by Cox regression analysis, and survival was described by Kaplan-Meier curves.
Results: Significant reductions in mean pulmonary arterial pressure (mPAP; p<0.001), pulmonary vascular resistance (PVR; p<0.001) and an increase in mixed venous oxygen saturation following NO inhalation were demonstrated (p<0.001) by a paired t-test. Stepwise multivariate analysis revealed the relative change of PVR after NO inhalation as a predictor of survival. Patients whose PVR during NO inhalation declined below 789.8 dynes.s.cm-5 had significantly better outcome than patients with above median PVR. There was a strong negative correlation between the relative change of PVR under NO and recurrent pulmonary hypertension after PEA (p=0.02).
Conclusions: Patients with operable CTEPH demonstrated acute pulmonary vascular reactivity, mostly not corresponding to a complete responder status, but accounting for a wide range of decreases of mPAP [change of mPAP (%) (−10.9Â±14)] and PVR [change of PVR (%) (−17 Â±15)]. Reduction of PVR under 800 dynes.s.cm-5 after inhalation of NO was associated with better outcome. Responsiveness to inhaled nitric oxide is a predictor for mid-term survival in adult patients with CTEPH undergoing PEA.