A mean pulmonary artery pressure >25 mm Hg at rest or pulmonary artery systolic pressure >35 mm Hg is considered abnormal.
Pulmonary arterial hypertension has been observed in all connective tissue disease, but most frequently in systemic scleroderma (SSc).
It is and has often been classified into two separate categories: primary pulmonary (arterial) hypertension, presently more often called idiopathic pulmonary arterial hypertension (iPAH) and secondary pulmonary arterial hypertension.
Secondary pulmonary arterial hypertension is more common than iPAH. Secondary pulmonary arterial hypertension is the common pathophysiologic mechanism leading to cor pulmonale in patients with underlying pulmonary disease (e.g. chronic obstructive pulmonary disease - COPD, pulmonary embolisms)
Secondary pulmonary arterial hypertension
