Journal article
Hypercapnic ventilatory response in epilepsy patients treated with VNS: A case-control study
Epilepsia (Copenhagen), Vol.62(9), pp.e140-e146
09/2021
DOI: 10.1111/epi.16997
PMCID: PMC9113047
PMID: 34265074
Abstract
Central CO
chemoreception (CCR), a major chemical drive for breathing, can be quantified with a CO
re-breathing test to measure the hypercapnic ventilatory response (HCVR). An attenuated HCVR correlates with the severity of respiratory dysfunction after generalized convulsive seizures and is a potential biomarker for sudden unexpected death in epilepsy (SUDEP) risk. Vagus nerve stimulation (VNS) may reduce SUDEP risk, but for unclear reasons the risk remains higher during the first 2 years after implantation. The vagus nerve has widespread connections in the brainstem, including key areas related to CCR. Here we examined whether chronic electrical stimulation of the vagus nerve induces changes in CCR.
We compared the HCVR in epilepsy patients with or without an active VNS in a sex- and age-matched case-control study. Eligible subjects were selected from a cohort of patients who previously underwent HCVR testing. The HCVR slope, change in minute ventilation (VE) with respect to change in end tidal (ET) CO2 (∆ VE/ ∆ ETCO2) during the test was calculated for each subject. Key variables were compared between the two groups. Univariate and multivariate analyses were carried out for HCVR slope as dependent variable.
A total of 86 subjects were in the study. HCVR slope was significantly lower in the cases compared to the controls. Cases had longer duration of epilepsy and higher number of anti-epileptic drugs (AEDs) tried during lifetime. Having active VNS and ETCO2 were associated with a low HCVR slope while high BMI was associated with high HCVR slope in both univariate and multivariate analyses.
We found having an active VNS was associated with relatively attenuated HCVR slope. Although duration of epilepsy and number of AEDs tried during lifetime was significantly different between the groups, they were not predictors of HCVR slope in subsequent analysis.
Chronic electrical stimulation of the vagus nerve by VNS may be associated with an attenuated CCR [Correction added on 24 November 2021, after first online publication: The preceding sentence has been revised from “Chronic electrical stimulation of VNS nerve by VNS…”]. A larger prospective study may help to establish the time course of this effect in relation to the time of VNS implantation, whether there is a causal relationship, and determine how it affects SUDEP risk.
Details
- Title: Subtitle
- Hypercapnic ventilatory response in epilepsy patients treated with VNS: A case-control study
- Creators
- Rup K Sainju - Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, USADeidre N Dragon - University of IowaHarold B Winnike - University of IowaPatrick Ten Eyck - University of IowaMark A Granner - University of IowaBrian K Gehlbach - Roy J. and Lucille A. Carver College of MedicineGeorge B Richerson - Roy J. and Lucille A. Carver College of Medicine
- Resource Type
- Journal article
- Publication Details
- Epilepsia (Copenhagen), Vol.62(9), pp.e140-e146
- DOI
- 10.1111/epi.16997
- PMID
- 34265074
- PMCID
- PMC9113047
- NLM abbreviation
- Epilepsia
- ISSN
- 0013-9580
- eISSN
- 1528-1167
- Grant note
- R01 NS113764 / NINDS NIH HHS UL1 TR002537 / NCATS NIH HHS U01 NS090414 / NINDS NIH HHS
- Language
- English
- Date published
- 09/2021
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Clinical Research Unit; Iowa Neuroscience Institute; Biostatistics; Neurosurgery; Health, Sport, and Human Physiology ; Internal Medicine
- Record Identifier
- 9984303024802771
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