Pulmonary HTN: Defined as mPAP>25 mmHg on right heart cath

WHO class Group 1 to Group 5

Group 1 (Pulmonary arterial hypertension)
-Idiopathic
-Heritable
-Drug and Toxin induced (toxic rapeseed oil, fenfluramine, likely methamphetamine, cocaine)
-Connective tissue Disease
–HIV
–Portopulmonary HTN
-Congenital heart disease
-Schistosomiasis
-Chronic hemolytic anemia (eg: SCD)
Group 2 (due to left heart disease)

-Systolic/diastolic dysfunction
-Valvular disease (aortic/mitral)

Group 3 (Due to lung disease or hypoxia)
-COPD -ILD, Pulmonary fibrosis
-Chronic exposure to high altitude

Group 4 (Chronic thromboembolic pulmonary  hypertension) 
-Recurrent PE

Group 5 (multifactorial)

-Hematologic disorders (myeloproliferative disorders)
-Systemic disorders (sarcoidosis, LAM, vasculitis)
-Metabolic disorders (glycogen storage diseases)

Vasoreactivity test

-Done with right heart cath to see if patient will respond to CCB.
-Most commonly iNO given during right heart cath and positive test is if mean pulmonary artery pressure decreases by at least 10 to a value less than 40.

Treatment

Group 1 PAH- No effective primary therapy, usually need advanced therapy (must confirm diagnosis with right heart cath)

a)Prostacyclins
b)Endothelin receptor antagonists
c)PDE5 inhibitors (eg: sildenafil)
d)iNO
e)CCB (if positive vasoreactivity test)

Group 2 PH- treat left heart disease
Group 3 PH: OXYGEN + CPAP (if due to OSA)
Group 4: Anticoagulation and Surgical Thromboendarterectomy
Group 5: varies based on etiology.