Sotatercept lowers blood volume but increases exercise ability

In a study of a relatively low-risk population of pulmonary hypertension patients, researchers began to untangle sotatercept's complex effects on exercise. Sotatercept lowered blood volume to normal levels and increased hemoglobin, allowing greater oxygen delivery during exercise. As well, muscles seemed to be able to extract more oxygen. At rest, people's bodies maintained oxygen delivery levels as the blood volume decreased, and the heart seemed to work less hard.

Cardiac output didn't increase, but because the blood had more hemoglobin and thus more oxygen, people felt better. Commonly used measures in this situation don't necessarily capture the improvements that people can feel and report.

Read the Journal of the American College of Cardiology article