Study: Robot-assisted Surgery Lowers Heart Strain, Improves Exercise Capacity in CTEPH Patients

Robot-assisted pulmonary artery denervation (PADN) — a minimally invasive surgical procedure that destroys some of the nerves innervating the pulmonary artery to reduce blood pressure — can lower heart strain and improve exercise capacity in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

That finding was reported in the study, “Pulmonary Artery Denervation for Patients With Residual Pulmonary Hypertension After Pulmonary Endarterectomy,” published in the Journal of the American College of Cardiology.

CTEPH is a rare and severe form of pulmonary hypertension (PH), in which increased blood pressure inside the pulmonary arteries — the blood vessels connecting the lungs to the heart — is caused by the presence of blood clots.

Pulmonary endarterectomy (PEA) — a surgical procedure that reduces blood pressure inside pulmonary arteries by removing blood clots and scar tissue — is the treatment of choice for those with CTEPH.

If successful, the procedure may ease patients’ symptoms dramatically, or even cure the disease. However, some patients may be left with residual signs of CTEPH after undergoing the procedure.

Investigators now have reported the findings of a study assessing whether PADN would be a safe and effective option to treat those who are left with residual CTEPH after undergoing PEA.

The randomized, blinded, sham-controlled study enrolled a total of 50 patients with residual CTEPH who continued to show signs of the disease despite treatment.

In the study, patients were assigned randomly to receive PADN or a sham intervention with Adempas (riociguat). PADN was performed using Stereotaxis’ Robotic Magnetic Navigation System to destroy nerves in the patients’ pulmonary arteries.

The main goal of the study was a change in pulmonary vascular resistance (PVR) — a measure of heart strain — over the course of a year. The study’s secondary goal was to assess changes in exercise capacity — assessed based on the six-minute walk test — over the same period of time.

Analyses showed that over the course of one year, patients who had undergone PADN had higher reductions in PVR compared to those who received the sham procedure — mean 258 vs. 149 dynes per second per centimeter (dyn‧s‧cm⁻⁵). Mean pulmonary artery pressure also was lower in the PADN group (25.8 mm Hg) compared to the sham group (33.8 mm Hg).

Patients who had PADN were able to cover longer distances in the six-minute walk test compared to controls (mean of 470 vs. 399 meters, or 513 vs. 436 yards).

“Our results demonstrate that pulmonary artery denervation may serve as an important new therapy for residual chronic thromboembolic pulmonary hypertension,” Alexander Romanov, MD, PhD, said in a press release. Romanov is from the E. Meshalkin National Medical Research Center and is first author of the study.

“The use of robotic technology enables the success of such procedures by enhancing [their] precision and safety. We are proud to be pioneering new therapies that can improve medical care and hope that this technology will be further tested in patients with different types of pulmonary hypertension,” Romanov said. 

PADN also was found to be safe, with only two patients (one from each group) developing a groin hematoma following the procedure. In both cases, this was resolved rapidly with no major consequences.

“We are delighted to see the strength of clinical benefits shown in this pioneering study,” said David Fischel, chairman and CEO of Stereotaxis.

“We have long known that Robotic Magnetic Navigation can broadly improve and enable interventional medicine. Pulmonary hypertension remains a disease with significant unmet medical need, and this therapy offers potential promise in one of the first non-arrhythmia indications for Stereotaxis to pursue,” Fischel added.