Vagal efficiency predicts response to external neurostimulation for abdominal pain
CHICAGO — Measuring vagal efficiency through respiratory sinus arrythmia in patients with functional abdominal pain could help predict therapeutic response to percutaneous electrical nerve field stimulation, according to research presented at the NASPGHAN Annual Meeting.
Percutaneous electrical nerve field stimulation (PENFS) is a relatively new treatment for functional abdominal pain that delivers neurostimulation through an external device on the ear.
“Vagal efficiency is extracted from the regression slopes of repeated samples of heart rate,” Katja Kovacic, MD, of the Medical College of Wisconsin, said in her presentation.
Kovacic said vagal efficiency shows how well the vagal brake can regulate the heart during shifts in posture, and individuals with low vagal efficiency may have more difficulties adjusting to stressors.
To determine if vagal efficiency could help predict response to PENFS, researchers enrolled 115 patients aged 11 years to 18 years in a double-blind, sham-controlled trial. They randomly assigned patients who had at least one functional abdominal pain disorder to receive PENFS therapy or sham stimulation. Investigators assessed abdominal pain using a composite pain score.
A subset of 87 patients underwent heart rate variability measurements before therapy, after 3 weeks, and 8 weeks to 12 weeks after therapy. Researchers performed electrocardiogram recording in during 3-minute posture shifts in supine, sitting and standing positions.
Patients in the treatment (n = 44) and sham (n = 43) groups had no difference in levels of baseline pain.
Kovacic and colleagues found that patients in the active PENFS group who had low vagal efficiency had reduced pain scores at week 3 compared with their pre-treatment scores.
“This may have lots of clinical relevance,” Kovacic said. “There are no biomarkers to any therapy for functional Gi disorders. Could this be a door into a simple test, a 9-minute test, to figure who may respond to therapies like this.” – by Alex Young
Kovacic K, et al. Abstract 217. Presented at: NASPGHAN; Oct. 17-19, 2019; Chicago.
Disclosures: Kovacic reports serving on the advisory board for Takeda Pharmaceuticals.