In the pulmonary arterial system, compliance is distributed over the entire arterial tree, resulting in a constant RC-time and proportionality of systolic and diastolic pressure with mean pressure.
The anatomical distribution of compliance in the pulmonary arterial system explains the constancy of the RC-time and the proportionality of systolic and diastolic pressures with mean pressure.
The anatomical differences between the pulmonary and systemic arterial system are the main cause of the difference in distribution of compliance. In the pulmonary arterial system compliance is distributed over the entire arterial system, and stands at the basis of the constancy of the RC-time. This distribution depends on the number of peripheral vessels, which is ∼8-10 times more in the pulmonary system than the systemic tree. In the systemic arterial tree the compliance is mainly located in the aorta (80% of total compliance in thoracic-abdominal aorta). The constant RC-time in the pulmonary bed results in proportionality of systolic and diastolic pressure with mean pressure and, in turn, in the constant ratio of oscillatory and mean power.
Saouti et al. (2010) conducted a review in Pulmonary hypertension. In the pulmonary arterial system, compliance is distributed over the entire arterial tree, resulting in a constant RC-time and proportionality of systolic and diastolic pressure with mean pressure.