Calcium channel blockers in patients with pulmonary arterial hypertension receiving PAH-specific treatment.

BACKGROUND: Calcium channel blockers (CCB) are the first effective therapy for vasoreactive patients with idiopathic pulmonary arterial hypertension (IPAH). However, the advent of modern PAH-specific drugs may undermine the role of vasoreactivity tests and CCB treatment. We aimed to clarify the effect of acute vasoreactivity testing and CCB on patients with IPAH receiving PAH-specific treatment. METHODS: We retrospectively investigated consecutive patients with IPAH (n = 136) diagnosed between 2000 and 2020 and collected data from patients who underwent acute vasoreactivity testing using inhaled nitric oxide (NO). The effects of vasoreactivity testing and CCB therapy were reviewed. Long-term survival was analysed using the Kaplan-Meier method. RESULTS: Acute vasoreactivity testing was performed in 49% of patients with IPAH (n = 67), including 23 patients (34%) receiving PAH-specific therapy without vasoreactivity testing. Eight patients (12%), including three patients (4.4%) receiving PAH-specific therapy, presented acute responses at vasoreactivity testing. They received high-dose CCB therapy (CCB monotherapy for five patients [7.5%] and CCB therapy and PAH-specific therapy for three patients [4.4%]). They presented a significant improvement in clinical parameters and near-normalisation of haemodynamics (mean pulmonary arterial pressure decreased from 46 [interquartile range: 40-49] to 19.5 [interquartile range: 18-23] mmHg [P < .001] at 1-year follow-up). All eight vasoreactive responders receiving CCB therapy showed better long-term survival than non-responders treated with PAH-specific therapy (P < .001). CONCLUSIONS: CCB therapy benefited patients with IPAH who showed acute response to vasoreactivity testing using inhaled NO, even when receiving modern PAH-specific therapy. Acute vasoreactive responders may benefit more from CCB than from PAH-specific therapy.

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.