Guest Editor's Commentary

This issue of the journal offers a simultaneous look at our past and future in the search for effective treatments for pulmonary arterial hypertension. Thanks to an ever-increasing number of randomized controlled trials, we now have the luxury of an evidence-based approach to therapy. Yet, although these treatment paradigms have improved patients' symptoms and outcomes, it is undeniably clear that we still have far to go. Combination therapy for pulmonary arterial hypertension provides a new and exciting approach with a growing body of evidence supporting its efficacy. At the same time a number of novel agents are working their way through early phase trials. It is truly an exciting time in the treatment of pulmonary arterial hypertension as we attempt to unlock the mysteries of this disease.