How is PAH treated?

There is currently no cure for Pulmonary arterial hypertension (PAH) but advances in understanding how the disease develops (see section: Why does PAH develop? ) means that there are now treatments available which have helped to improve prognosis for patients with this disease.

The main treatment options for patients with Pulmonary Arterial Hypertension (PAH) are:¹

Treatments that are routinely used but with little evidence of an impact on the disease:

• Anticoagulants, such as warfarin, to address the observed thrombotic changes and potential predisposition in the pulmonary microcirculation for in-situ thrombosis
• Diuretics, for treatment of right heart failure
• oxygen therapy,  to maintain oxygen saturation at > 90% at all times.
• calcium-channel blockers (CCBs). Less than 10% of IPAH patients benefit from CCBs therapy. This figure is even lower in other forms of Pulmonary Arterial Hypertension (PAH). If not used in appropriate candidates (patients with demonstrated vasoreactivity during Right heart catheterisation), CCBs can decrease cardiac output and systemic vascular resistance without any improvement in PAP and PVR and therefore may be deleterious.²

Treatments that have been specifically studied in Pulmonary Arterial Hypertension (PAH)

• endothelin receptor antagonists - endothelin is implicated in the pathogenesis of Pulmonary Arterial Hypertension (PAH) through actions on the pulmonary vasculature. Endothelin is found to be elevated in patients with Pulmonary Arterial Hypertension (PAH) and levels of endothelin are directly related to disease severity and prognosis. Endothelin receptor antagonists (ERAs) are oral treatments that either block the ET_A receptor alone  or both the ET_A and ET_B receptors.^3,4  
• Prostacyclin analogues - may be delivered by continuous intravenous or subcutaneous infusion or via an intermittent nebuliser.¹ To date, oral agents have shown limited effectiveness 
• phosphodiesterase 5 inhibitors - oral agents which induce relaxation and antiproliferative effects on vascular smooth muscle cells by preventing the reduction in levels of cGMP.⁵

In very severe cases surgical options may be considered:

• balloon atrial septostomy 
• heart and lung transplantation - the use of transplantation is constrained by the limited number of donor organs.

References
1. Humbert H et al. Treatment of  pulmonary arterial hypertension. N Engl J Med 2004; 351: 1425-36
2. Sitbon O, Humbert M, Jaïs X et al. Long-term response to Calcium channel blockers in idiopathic pulmonary arterial hypertension. Circulation 2005; 11:3105-11
3. Channick RN, Simonneau G, Sitbon O et al.  Effects of the dual endothelin-receptor antagonist bosentan in patients with pulmonary hypertension: a randomised placebo-controlled study.  Lancet 2001;358:1119-23
4. ESC Guidelines. Guidelines to diagnosis and treatment of pulmonary arterial hypertension. European Heart Journal 2004; 25:2243-78
5. Galiè N et al. Sildenafil citrate treatment for pulmonary arterial hypertension. N Engl J Med 2005; 353: 2148-57