ABSTRACT
Pulmonary arterial hypertension (PAH), defined as a mean pulmonary arterial pressure of greater than 25 mmHg in the absence of elevation of the pulmonary capillary wedge pressure, is a cause of significant morbidity and mortality (1). PAH is characterized by increased pulmonary vascular resistance due to remodeling and occlusion of the small pulmonary arterioles. Left untreated it leads irremediably to right ventricular (RV) hypertrophy, pressure overload, and dilation resulting in death within two to three years (1). PAH that encompasses a heterogeneous group of clinical entities sharing similar pathological changes can be associated with various connective tissue diseases (CTDs) such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and mixed CTD (MCTD).
