Usefulness of intravenous adenosine in idiopathic pulmonary arterial hypertension as a screening agent for identifying long-term responders to calcium channel blockers
The American Journal of Cardiology, 06/18/2012
Zuo XR et al. – Acute vasodilator testing with intravenous adenosine was safe and able to screen responders to calcium channel blocker (CCB) therapy in patients with idiopathic pulmonary arterial hypertension (IPAH). Long–term CCB responders accounted for about 5.8% of patients with IPAH.Methods
- Although intravenous adenosine is recommended for acute vasodilator testing in patients with pulmonary hypertension, long–term outcomes in acute responders treated with calcium channel blockers (CCBs) who are identified by adenosine remain unknown.
- In this study, the value of adenosine for identifying long–term responders to CCBs was investigated in patients with idiopathic pulmonary arterial hypertension (IPAH).
- All acute responders were subsequently treated with high–dose CCB monotherapy, and 6–minute walk distances, hemodynamic data, and World Health Organization functional classifications were followed.
- Nine of 104 patients exhibited an acute response with intravenous adenosine (8.7%, 95% confidence interval 3.2 to 14.2).
- After 12 months of follow–up, all acute responders were still alive; however, only 6 patients showed sustained hemodynamic improvement (5.8%, 95% confidence interval 2 to 13).
- Three patients had failed CCB monotherapy and bosentan was added to their treatment.
- Mean tolerated dose of intravenous adenosine was 142 ± 49 μg/kg/min.
- No life–threatening adverse events were observed and only 2 patients of the nonresponders exhibited a 20% decrease in mean systemic arterial pressure.
- In nonresponders, 1– and 3–year survival rates were 89% and 75%, respectively.