The role of calcium channel blockers for the treatment of pulmonary arterial hypertension: How much do we actually know and how could they be positioned today?

Calcium channel blockers (CCB) were the first vasodilator agents to gain popular acceptance in the treatment of pulmonary arterial hypertension (PAH). They have been shown to be particularly effective in patients who show a significant immediate hemodynamic response to pulmonary vasodilators ("responders"). The application of CCB is currently restricted to "responders" only. It is believed that no more than 5% of PAH patients will benefit from CCB long term. The response rate of most non-idiopathic forms of PAH is considered to be even lower. The "non-responders" as well as "responders" who fail to benefit from CCB should be treated with newer agents, collectively called "advanced PAH therapy." The basis of this consensus rests on empiric experience gained in the PAH community over the years. However, the cut-points where advanced agents are more effective than CCB and where there is no additional role for CCB remain unknown. In this manuscript, we review the data concerning this issue and postulate a role for CCB in the modern era of pulmonary hypertension therapy.