Pulmonary Artery Denervation to Treat Pulmonary Arterial Hypertension: A Single-Center, Prospective, First-in-Man PADN-1 Study

Study Questions:

What is the efficacy of pulmonary artery (PA) denervation (PADN) for patients with idiopathic PA hypertension (IPAH) not responding optimally to medical therapy?

Methods:

Out of a total of 21 patients with IPAH, 13 patients received the PADN procedure, and the other 8 patients who refused the PADN procedure were assigned to the control group. PADN was performed at the bifurcation of the main PA, and at the ostial right and left PA. Serial echocardiography, right heart catheterization, and a 6-minute walk test (6MWT) were performed. The primary endpoints were the change of PA pressure (PAP), tricuspid excursion (Tei) index, and 6MWT at 3-month follow-up.

Results:

Mean age was 40 years. All patients were on inhaled beraprost and anticoagulants, and 85% were on sildenafil. Compared with the control group, at 3-month follow-up, the patients who underwent the PADN procedure showed significant reduction of mean PAP (from 55 ± 5 mm Hg to 36 ± 5 mm Hg, p < 0.01); significant increase in cardiac index (from 2.0 ± 0.2 L/min/m2 to 2.8 ± 0.3 L/min/m2); significant improvement in the 6MWT (from 324 ± 21 m to 491 ± 38 m, p < 0.006); the Tei index (from 0.3 ± 0.04 to 0.50 ± 0.04, p < 0.001); and N-terminal B-type natriuretic peptide reduced from 2005 ± 442 pg/ml to 822 ± 201 pg/ml (p < 0.001) with no change in the control group.

Conclusions:

At 3 months following PADN, there was improved functional capacity and hemodynamics in patients with IPAH not responding optimally to medical therapy. Further randomized study is required to confirm the efficacy of PADN.

Perspective:

The patients are relatively typical of IPAH, but for the low baseline mean renal artery (4 mm Hg) and very low mixed venous oxygen saturation (42%), suggesting they were dehydrated at baseline. The effect of PADN in IPAH in this very small study is truly remarkable. No other available treatment for IPAH has produced anywhere near the degree of reduction in mean PAP or increase in 6MWT at 12 weeks. As with renal artery sympathetic denervation for systemic hypertension, the technique is very encouraging, but much is to be done prior to clinical applicability including much larger and placebo-controlled studies of safety and efficacy, and long-term follow-up.

Clinical Topics: Dyslipidemia, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Pulmonary Hypertension and Venous Thromboembolism, Lipid Metabolism, Pulmonary Hypertension, Echocardiography/Ultrasound, Hypertension

Keywords: Follow-Up Studies, Epoprostenol, Denervation, Purines, Cardiac Catheterization, Piperazines, Sulfones, Hemodynamics, Natriuretic Peptides, Renal Artery, Sympathectomy, Hypertension, Pulmonary, Oxygen, Pericardium, Neurosurgical Procedures, Hypertension, Echocardiography, Exercise Test


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