Loss of response to calcium channel blockers after long-term follow up in idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a condition characterized by remodeling of small pulmonary arteries. However, vasoconstriction can play an important role in the development of disease. Previous studies showed that some IPAH patients present acute response to vasodilators and benefit from treatment with calcium channel blockers (CCB). Patients who present sustained response to CCB after 1 year have better survival. Nevertheless, it is still unknown the proportion of patients that remains responsive to CCB after longer periods. Our study aimed to evaluate the long-term sustainability of clinical response to CCB. We evaluated data from all 26 consecutive IPAH patients with acute response to vasodilator challenge, from January 2003 to December 2018. IPAH diagnosis followed criteria from 2015 ESC/ERS Guidelines. Four patients were considered short-term responders because they failed treatment with CCB in less than 1 year. Eleven patients were considered true responders, improving with CCB treatment and remaining clinically stable during the whole follow-up period. Eleven patients presented clinical worsening after a mean follow-up of 47 months and so were considered with loss of long-term response to CCB. Our data suggest that one year of clinical response to CCB in IPAH with response to vasodilator challenge is not enough to predict long-term benefit and better survival.