Pulmonary arterial hypertension sensitive to calcium channel blocker, but not advanced pulmonary hypertension treatment: a case report.

Background: Calcium channel blockers (CCB), the first accepted treatment, is effective only in a small number of idiopathic pulmonary arterial hypertension (I-PAH) patients with vasoreactivity [these patients are identified by a positive acute pulmonary vasoreactive test (AVT) response]. While the majority of I-PAH patients is non-vasoreactive and CCB non-responders, modern advanced pulmonary hypertension (PH)-specific therapies, which act on one of the three different mechanistic pathways-endothelin, nitric oxide (NO), and prostacyclin pathways, are effective. Treatment response to advanced PH-specific vasodilators in PAH patients with vasoreactivity is unknown. Case summary: A 30-year-old woman with I-PAH was referred to our centre with worsening symptoms and deteriorating PH. She was being administered oral triple combination of advanced PH-specific treatment including a phosphodiesterase-5 inhibitor, an endothelin receptor antagonist, and a long-acting prostacyclin analogue. The patient showed positive AVT with NO inhalation while on these advanced PH-specific drugs. We added high-dose CCB, which dramatically normalized her pulmonary blood pressure without further symptoms, and she has remained stable for 5 years. Discussion: Our case describes a PAH patient with vasoreactivity, who was resistant to three different types of advanced PH-specific vasodilators but was exclusively sensitive to CCB treatment. Some CCB responders may have a specific CCB-sensitive PAH phenotype refractory to other pulmonary vasodilators. This case highlights the role of identifying CCB responders in this era of use of modern, advanced PH-specific vasodilators. The investigation of the mechanisms underlying CCB sensitivity in PAH is necessary.