Upfront triple combination therapy in pulmonary arterial hypertension: a pilot study.

Patients with severe pulmonary arterial hypertension (PAH) in New York Heart Association (NYHA) functional class (FC) III/IV have a poor prognosis, despite survival benefits being demonstrated with intravenous epoprostenol. In this pilot study, the efficacy and safety of a triple combination therapy regimen in patients with severe PAH was investigated. Data from newly diagnosed NYHA FC III/IV PAH patients (n=19) initiated on upfront triple combination therapy (intravenous epoprostenol, bosentan and sildenafil) were collected retrospectively from a prospective registry. Significant improvements in 6-min walk distance and haemodynamics were observed after 4 months' triple combination therapy in 18 patients (p<0.01); 17 patients had improved to NYHA FC I or II. One patient was not included in the month 4 assessment (due to an emergency lung transplant in month 3). At the final evaluation (mean ± sd 32 ± 19 months), all 18 patients had sustained clinical and haemodynamic improvement. Overall survival estimates for the triple combination cohort were 100% at 1, 2 and 3 years. Expected survival calculated from the French equation was 75% (95% CI 68-82%), 60% (95% CI 50-70%) and 49% (95% CI 38-60%) at 1, 2 and 3 years, respectively. This pilot study provides preliminary evidence of the long-term benefits of upfront triple combination therapy in patients with severe PAH.

Calcium-channel blockers in pulmonary arterial hypertension.

Voltage-activated calcium channels are a family of membrane proteins that provide the major influx pathway for calcium in many different types of cells. Calcium-channel blockers inhibit the calcium influx into vascular cells leading to relaxation of smooth muscle cells and vasodilatation. Vasoconstriction of small pulmonary arteries is recognized as a component of the pathogenesis of pulmonary arterial hypertension and treatment with calcium-channel blockers appears to be rational in this setting. No randomized controlled trial has been performed to demonstrate the beneficial effects of calcium-channel blockers in the treatment of patients with pulmonary arterial hypertension. However, uncontrolled studies have suggested that long-term administration of high-dose calcium antagonists dramatically improves survival in a small subset of patients who respond acutely to those drugs, compared with unresponsive patients. The initial response to an acute vasodilator test with inhaled nitric oxide or intravenous prostacyclin or adenosine accurately identifies patients with pulmonary arterial hypertension who are likely to respond to long-term treatment with calcium-channel blockers.