A cross-sectional study found that patients who had laryngopharyngeal symptoms had reduced baroreflex sensitivity compared with those who had esophagogastric symptoms, suggesting a diminished vagal control.
In the study, published in JAMA Otolaryngology–Head & Neck Surgery, investigators compared autonomic measures in 53 adult patients undergoing esophageal manometry or transnasal panendoscopy at a specialist center.
Heart rate and blood pressure were recorded using a 3-lead electrocardiogram and finger photoplethysmography transducer, respectively. Baroreflex sensitivity (BRS) and heart rate variability were derived from these measurements. Esophageal physiology was assessed with high-resolution manometry in the digestive group and selected aerodigestive patients. The investigators used the Multiple Trigonometric Regressive Spectral (MTRS) method to calculate BRS from a short hemodynamic segment. Measurements were taken in an upright position without medications or a tilt table. Hemodynamic measurements were taken between the start of the second and fourth minutes of monitoring for resting hemodynamics. BRS calculation used data from 60 seconds before the start of the first timed inspiration to 60 seconds after the start of the last timed inspiration.
Among the key findings were:
- Patients in the aerodigestive group (n = 23) had significantly lower mean BRS compared with the digestive group (n = 30): 3.77 vs 9.76 s^–3 mmHg^–1 (odds ratio [OR] = 6.0 s^–3 mmHg^–1, 95% confidence interval [CI] = 4.7–7.2).
- The aerodigestive group showed lower parasympathetic-spectrum heart rate variability: 0.68 vs 1.30 (OR = 0.62, 95% CI = 0.39–0.85).
- Resting heart rate was higher in the aerodigestive group: 93 vs 75 min^–1 (difference of means = –18 min^–1, 95% CI = –26 to –10).
- Mean arterial pressure was lower in the aerodigestive group: 94 vs 104 mmHg (OR = 10, 95% CI = –1 to 21).
- A weak correlation was observed between reduced lower esophageal relaxation (integrated relaxation pressure) and reduced BRS (r = –0.33, 95% CI = –0.58 to –0.03).
The study population had a mean age of 61 (standard deviation [SD] = 15) years and included 26 women and 27 men. The patients in the aerodigestive group were more likely to report voice or throat symptoms (OR = 5.65, 95% CI = 1.82–17.5) and less likely to report classic reflux symptoms (OR = 0.60, 95% CI = 0.38–0.95) compared with the digestive group.
Additional participant characteristics included:
- Current or former smokers: 52% in the aerodigestive group vs 13% in the digestive group (OR = 7.09, 95% CI = 1.87–26.9).
- Weekly alcohol intake: 95% in the aerodigestive group vs 70% in the digestive group (OR = 2.03, 95% CI = 0.54–7.71).
Specific symptom prevalence:
- Dysphagia: 61% in aerodigestive group vs 40% in digestive group (OR = 1.52, 95% CI = 0.88–2.63).
- Odynophagia: 17% in aerodigestive group vs 23% in digestive group (OR = 0.75, 95% CI = 0.25–2.24).
- Daily dry cough for > 8 weeks: 39% in aerodigestive group vs 63% in digestive group (OR = 0.62, 95% CI = 0.35–1.1).
- Hoarseness: 57% in aerodigestive group vs 10% in digestive group (OR = 5.65, 95% CI = 1.82–17.5).
- Painless throat symptoms: 83% in aerodigestive group vs 40% in digestive group (OR = 2.07, 95% CI = 1.28–3.33).
- Classic gastroesophageal reflux disease symptoms: 48% in aerodigestive group vs 80% in digestive group (OR = 0.6, 95% CI = 0.38–0.95).
Detailed hemodynamic data included:
- Systolic blood pressure: 146 (SD = 21) mmHg in aerodigestive group vs 150 (SD = 25) mmHg in digestive group (difference of means = 6, 95% CI = –9 to 17).
- Diastolic blood pressure: 68 (SD = 17) mmHg in aerodigestive group vs 81 (SD = 23) mmHg in digestive group (difference of means = 13, 95% CI = 2 to 24).
Esophageal physiology measurements showed:
- Distal Contractile Integral (DCI): 1,213 (SD = 1,266) mmHg·s·cm in aerodigestive group vs 499 (SD = 496) mmHg·s·cm in digestive group (difference of means = –714, 95% CI = –1,265 to –163).
- Integrated Relaxation Pressure: 4.8 (SD = 4.6) mmHg in aerodigestive group vs 2.1 (SD = 2.5) mmHg in digestive group (difference of means = –2.7, 95% CI = –4.9 to –0.5).
- DeMeester score: 13.4 (SD = 11.5) in aerodigestive group vs 26.3 (SD = 24.7) in digestive group (difference of means = 12.9, 95% CI = 2.2 to 28).
- Distal acid exposure time: 3.9% (SD = 3.8%) in aerodigestive group vs 7.2% (SD = 6.5%) in digestive group (difference of means = 3.3%, 95% CI = –0.8 to 7.4).
Patient-reported outcome measures for the aerodigestive group included:
- Voice Handicap Index (10 item): mean 5.6 (SD = 8.3, range, 0–30).
- Eating Assessment Tool: mean 9.6 (SD = 11.7, range, 0–35).
- Glasgow-Edinburgh Throat Scale: mean 17.1 (SD = 16.9, range = 0–58).
The findings suggested that laryngopharyngeal sensorimotor dysfunction might "overwhelm" the autonomic system, deprioritizing less immediate functions like blood pressure stabilization.
The investigators highlighted that while the results of the study demonstrated an association between laryngopharyngeal symptoms and autonomic dysfunction, causality was not established. They noted several limitations, including the cross-sectional design and potential selection bias. Future studies are needed to further explore the overwhelmed vagus hypothesis and its clinical implications.
The authors declared having no competing interests.