SAN DIEGO (FRONTLINE MEDICAL NEWS)Percutaneous pulmonary artery denervation for the treatment of pulmonary arterial hypertension safely resulted in significantly greater improvement in functional capacity and hemodynamics compared with medication, in a controlled before-and-after study.

A particularly noteworthy secondary finding in the study was that rehospitalizations during the first 6 months after pulmonary artery denervation (PADN) occurred just one-third as frequently as in the 6-month preprocedural period on standard medications, Dr. Shao-Liang Chen said at the annual meeting of the American College of Cardiology.

He and his coinvestigators, including Dr. Gregg W. Stone of Columbia University in New York, developed a percutaneous catheter-based method of destroying the pulmonary baroreceptor structure located at the bifurcation area of the middle pulmonary artery. Along the way, they redefined the understanding of the pathogenesis of pulmonary artery hypertension (PAH) by demonstrating that local sympathetic nerve activity plays a pivotal role in modulating the elevations of mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR), which are the disease hallmarks.

Dr. Chen and coinvestigators previously reported the first-in-man study of PADN, which demonstrated safety and short-term efficacy ( J. Am. Coll. Cardiol. 2013;62:1092-100 ). At ACC 15, Dr. Chen presented the findings of the new PADN-2 study, which expands upon the first study by including more patients and longer and more comprehensive follow-up.

The study comprised 28 patients with PAH, including 11 with idiopathic PAH and 8 with pulmonary hypertension caused by left ventricular disease. All of them underwent medication washout followed by right heart catheterization and echocardiography for baseline off-drug hemodynamic measurements as well as a 6-minute walk distance test of their functional capacity. Then they went back on medications for 6 months, after which they underwent repeat testing. Then their medications were discontinued and they underwent PADN. Six months after the procedure, still off medications, they were retested once again.

The primary study endpoint was change in 6-minute walk distance. After 6 months of medication it improved from 361 to 373 meters, a modest 3.9% gain over off-drug baseline. In contrast, 6-minute walk distance grew from 358 to 423 meters 6 months after PADN, a clinically important 23.9% improvement, reported Dr. Chen, a cardiologist at First Hospital of Nanjing (China) Medical University.

Multiple secondary hemodynamic endpoints also showed significantly greater improvement with PADN than medical therapy.

Twelve predefined clinical events – mostly involving worsening PAH – occurred during medical management, compared with three in the 6 months following PADN.

In addition, there were 12 hospitalizations during the 6 months on medical management compared with only 4 after the same patients underwent PADN. Health care costs averaged $35,000 per patient during the 6-month study period on medication compared with $6,000 per patient in the first 6 months after PADN.

There were no deaths, aneurysms, access site hematomas, or thrombotic events during either study period.

Further randomized, controlled trials are planned to explore the possibility that the benefits seen in the PADN-2 trial will result in reduced mortality in patients with PAH, according to Dr. Chen.

The PADN-2 trial was sponsored by Nanjing Medical University. Dr. Chen reported serving as a consultant to MicroPort.