Related Experiment Video
Updated: Jun 3, 2026
Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise
Published on: February 20, 2017
Effects of pulmonary vasodilator therapy on ventilatory efficiency during exercise in adults with Eisenmenger
Showshan Yang-Ting1, Jamil Aboulhosn, Xing-Guo Sun
1Kaiser Permanente Medical Center, Downey, CA, USA.
Objective:
Eisenmenger syndrome, characterized by systemic-level pulmonary arterial resistance with resultant right-to-left shunt, is associated with low exercise capacity and hyperpnea at rest and exercise. Because ventilatory requirements are augmented by right-to-left shunting, we hypothesized that if pulmonary vasodilator treatment improved pulmonary perfusion in this condition, this would also improve ventilatory efficiency during exercise.
Design:
To investigate this, data from incremental cardiopulmonary exercise tests performed by Eisenmenger patients before and after beginning therapy with pulmonary hypertension medications were retrospectively analyzed. Setting. Ahmanson/University of California, Los Angeles Adult Congenital Heart Disease Center.
Patients:
Ten adults with Eisenmenger syndrome treated with either bosentan or sildenafil.
Outcome Measures:
The primary analysis was comparison, before and after treatment, of the efficiency of exercise ventilation as reflected in the ratio of ventilation (.V(E)) to carbon dioxide output (.VCO₂) measured at the anaerobic threshold (AT), the slope of .V(E)/.VCO₂ during incremental exercise, and end tidal partial pressure of CO₂ (PETCO₂) at the AT. Secondary measures included peak oxygen uptake (.VO₂) and AT.
Results:
Following treatment there were significant reductions in the slope .V(E)/.VCO₂ (59.5 ± 12.9 vs. 50.0 ± 7.2, P= .003), and significant decrease in .V(E)/.VCO₂ ratio (56.9 ± 6.2 vs. 50.2 ± 5.9, P= .00004) and increase in PETCO₂ (21.12 ± 2.43 vs. 23.9 ± 2.62 torr, P= .0092) measured at the AT. Increases in peak .VO₂ (0.73 ± 0.25 vs. 0.78 ± 0.32 L/min, P= .333) and AT (0.61 ± 0.20 vs. 0.68 ± 0.25 L/min, P= .154) were not significant.
Conclusions:
These findings are consistent with reduction in right-to-left shunt due to improved pulmonary blood flow, though attenuation of ventilatory drive is not excluded. Treatment of adult Eisenmenger patients with pulmonary the pulmonary vasodilators bosentan or sildenafil leads to improvement in parameters of ventilatory efficiency during exercise.
Related Concept Videos
01:16Treatment for Pulmonary Arterial Hypertension: Oxygen Therapy for Respiratory Failure
Oxygen therapy is vital in increasing and maintaining blood oxygen levels in PAH patients. As a result, it aids in reducing fatigue, improving...
01:19Factors Affecting Pulmonary Ventilation
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
01:28Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
01:18Treatment for Pulmonary Arterial Hypertension: Endothelin Receptor Antagonists
ETs are synthesized through a complex sequence of enzymatic steps, primarily involving an enzyme referred to as endothelin-converting enzyme (ECE). Of...