ABSTRACT
Introduction to the pathophysiology of PAH Our understanding of the pathophysiology of PAH is still in its infancy, although significant advances have been made based on molecular science, genetics, and the understanding of the clinico-pathological interactions recognized in the WHO classification scheme. Undoubtedly, the pathophysiology of PAH is complex, pivoting around the concepts of vasoconstriction, vascular remodelling, and thrombosis. Vasoactive substances, growth factors, inflammatory mediators, and components of the clotting/coagulation system are all involved to varying degrees.24 This complex interplay is only just being decoded, but already there have been both real and potential therapeutic targets unearthed. This chapter will discuss some of the underlying mechanisms and mediators responsible for (or associated with) the development of PAH, and how these interact to cause the problems encountered in clinical practice.
