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Ultrasound-Based Denervation Gains Traction in PAH

PARIS — Ultrasound-based denervation helped patients with pulmonary arterial hypertension (PAH) when medical therapy was not enough, the TROPHY1 study indicated.

Improvements in pulmonary hemodynamics were observed 4-6 months among the 23 patients who underwent pulmonary artery denervation with SoniVie’s TIVUS therapeutic intravascular ultrasound system:

  • Pulmonary artery pressure reduced (looking at minimum, maximum, and median values)
  • Pulmonary vascular resistance down from ~675 to ~575 dyn·sec/cm5
  • Right atrial pressure down from ~10.5 to ~8.0 mm Hg
  • Pulmonary arterial compliance increased from ~1.6 to ~1.9 mL/mm Hg

As late as 8 months, patients improved 6-minute walk distances by around 40m and daily step counts by approximately 800 steps, Alex Rothman, BM BCh, PhD, of the University of Sheffield Medical School, England, showed the audience here at EuroPCR.

Harrison Farber, MD, of Boston University, commented that these were “very promising” data that will nonetheless need further confirmation.

Pulmonary artery denervation is thought to work for PAH because the associated vascular constriction and remodeling may be signs of a sympathetic system on overdrive, Rothman said.

The non-occlusive ultrasound procedure heats up nerves to over 116 ºF (47 ºC) at a depth of 0.4 in (10 mm), according to prior computer simulation and ex vivo studies by his group.

Eight centers (from Europe, the U.S., and Israel), participated in the present study. Patients were in WHO functional class III despite best medical therapy. Average age was 60 years and 78% of the cohort were women. In half of the group, PAH was associated with connective tissue disease; the condition was idiopathic in about one-third and drug-induced in the rest.

No procedure-related serious adverse events were reported after denervation. However, there were 11 hospitalizations for PAH.

Patients did not change their PAH medications over the course of the study.

Rothman disclosed honoraria from SoniVie.