Researchers discovered that patients’ breathing reserve at peak exercise was not associated with disease outcomes in idiopathic pulmonary arterial hypertension (IPAH), as published in the International Journal of Cardiology Congenital Heart Disease.
In contrast, they found an association between breathing reserve >30% at peak exercise and improved survival rates in patients with Eisenmenger syndrome (EIS).
“Reduced [breathing reserve] did not predict survival in patients with IPAH, although the follow-up duration was shorter in the IPAH group [when compared to EIS group],” they said.
Read more about PAH types
Half of the patients with EIS and 33.3% of the patients with IPAH had breathing reserves of ≤30% at peak exercise (P =.047). Patients with EIS who had breathing reserves >30% showed superior 10-year transplant-free survival rates and lower risks of mortality when compared to those with breathing reserves ≤30%.
Breathing reserve at peak exercise was measured during cardiopulmonary exercise testing. The study enrolled 50 patients in each group (ie, IPAH and EIS). Patients in the IPAH group were older and had higher peak
oxygen uptakes than those in the EIS group. Also, all patients were on advanced pulmonary vasodilator therapies for PAH.
Since the available follow-up duration in patients with IPAH was shorter than in the EIS group, the authors believe the long-term prognostic value of breathing reserve could not be accurately measured in the former group.
Moreover, they recognized difficulties in determining the impact of advanced pulmonary vasodilator therapies on the results obtained due to the heterogeneity of treatment approaches used in patients from each group.
Samaranayake CB, McNiven R, Kempny A, et al. Exercise ventilatory reserve predicts survival in adult congenital heart disease associated pulmonary arterial hypertension with Eisenmenger physiology. Int J Cardiol Congenit Hear Dis. Published online January 13, 2022. doi:10.1016/j.ijcchd.2022.100331