SAN DIEGO – Pulmonary artery denervation is efficacious for treating combined pre- and postcapillary pulmonary hypertension attributable to left heart failure, based on results of the Chinese PADN-5 trial reported at the Transcatheter Cardiovascular Therapeutics annual meeting.
Susan London/MDedge News
Dr. Shao-Liang Chen
This ablative treatment has been studied among patients with pulmonary hypertension attributable to other etiologies, but not in randomized fashion among this population, noted lead investigator Shao-Liang Chen, MD, of Nanjing (China) First Hospital, Nanjing Medical University. The treatment is an attractive one, as medications recommended for pulmonary arterial hypertension are not recommended for joint pre- and postcapillary pulmonary hypertension (group II pulmonary hypertension).
In PADN-5, 98 patients were randomized to pulmonary artery denervation or to sham denervation plus open-label sildenafil (Viagra), which at the time of trial initiation was thought to be safe and potentially beneficial.
The trial’s main outcome, 6-minute walk distance at 6 months, improved in both groups, according to data reported at the meeting and simultaneously published in JACC Cardiovascular Interventions. But the improvement was about four times greater in the pulmonary artery denervation group. Secondary efficacy outcomes also favored that group, and the rate of fatal pulmonary embolism did not differ for the two groups.
“The PADN-5 trial demonstrates the benefits of pulmonary artery denervation for patients with combined pre- and postcapillary pulmonary hypertension. Patients with preserved and with reduced ejection fraction equally benefited,” summarized Dr. Chen, who pioneered this procedure about 7 years ago. “There was no sign of any harm of sildenafil in patients with combined pre- and postcapillary pulmonary hypertension.”
Trial critique
“This is a very difficult study to conduct, being able to recruit patients and actually have these procedures done,” commented press conference moderator Ori Ben-Yehuda, MD, professor of clinical medicine and director, coronary care unit, UC San Diego Medical Center.
At the same time, he expressed some reservations about the trial. “Sildenafil in the control group might actually be expected to ... decrease your effect size. Also, particularly in men, perhaps even in women, it might unblind them to which group they are in and undermine your sham design,” he noted. In addition, some hemodynamic changes after pulmonary artery denervation – a decrease in wedge pressure and an increase in ejection fraction – were puzzling.
“We need a lot more data here. There are some issues with this trial in terms of design, and we haven’t even gotten into the issue of whether there were core labs, whether the echoes, the hemodynamics, were read blindly,” Dr. Ben-Yehuda maintained. “This issue of secondary or group II pulmonary hypertension due to left heart failure is one that has been very frustrating in terms of actual PA-specific therapies. So this is an important step further, but it needs confirmation in truly sham-controlled trials that have no potential for unblinding.”
The catheter used in PADN-5 is available in China but has not received clearance in the United States, he pointed out. “There are alternative or competing technologies, one using ultrasound, for example, that has a very similar approach. … We’ll have to see how it ends up [performing].”