Abstract
Despite developments in the treatment of pulmonary arterial hypertension, timely treatment is seldom achieved, and hidden progression is not uncommonly disguised as a seemingly "stable" condition. Appropriate risk assessment tools facilitate goal-oriented treatment strategies. This article aimed to review the development of these risk assessment tools including early assessment equations/scores, European guidelines-based risk assessment scores, and tools derived from the United States nationwide registry. A stepwise and regular approach with these assessment tools in clinical practice is highly recommended for timely treatment escalation to stop disease progression early. In this review, a practical and recommended algorithm of these assessment tools is also provided.