Esophageal balloon distention and cerebral evoked potential recording in the evaluation of unexplained chest pain

Meta-analysis: the epidemiology of noncardiac chest pain in the community

BACKGROUND

Prevalence of, and risk factors for, noncardiac chest pain in the community have not been well studied.

AIMS

To conduct a systematic review and meta-analysis to examine these issues.

METHODS

MEDLINE, EMBASE and EMBASE Classic were searched (up to March 2011) to identify population-based studies reporting prevalence of noncardiac chest pain in adults (≥15 years) according to self-report, questionnaire or specific symptom-based criteria. Prevalence of noncardiac chest pain was extracted for all studies, and according to study location and certain other characteristics including presence or absence of gastro-oesophageal reflux disease (GERD) symptoms, where reported. Pooled prevalence overall, as well as odds ratios (OR), with 95% confidence intervals (CIs) were calculated.

RESULTS

Of 18 articles evaluated, 16 reported prevalence of noncardiac chest pain in 14 separate populations, containing 24 849 subjects. Pooled prevalence of noncardiac chest pain in all studies was 13% (95% CI 9-16). The prevalence of noncardiac chest pain was higher in Australian studies and in studies using a questionnaire to define its presence, compared with those using Rome I or II criteria. Prevalence was no different in women vs. men (OR 0.99; 95% CI 0.82-1.20). The prevalence was markedly higher in subjects who also reported GERD (OR 4.71; 95% CI 3.32-6.70) and increased according to frequency of GERD symptoms.

CONCLUSIONS

Pooled prevalence of noncardiac chest pain in the community was 13%, but there were few studies. Rates did not appear to differ according to gender or age. Presence of GERD was strongly associated with noncardiac chest pain.

Non-cardiac chest pain: prevalence of reflux disease and response to acid suppression in an Asian population

BACKGROUND

Gastroesophageal reflux disease is thought to be the commonest cause of 'non-cardiac chest pain'. The use of proton-pump inhibitors resulting in improvement in the chest pain symptom would support this causal association.

OBJECTIVES

To determine the prevalence of gastroesophageal reflux disease in non-cardiac chest pain and the response of chest pain to proton-pump inhibitor therapy.

METHODS

Patients with recurrent angina-like chest pain and normal coronary angiogram were recruited. The frequency and severity of chest pain were recorded. All patients underwent esophagogastroduodenoscopy and 48-h Bravo ambulatory pH monitoring before receiving rabeprazole 20 mg bd for 2 weeks.

RESULTS

The prevalence of gastroesophageal reflux disease was 66.7% (18/27). The improvement in chest pain score was significantly higher in reflux compared to non-reflux patients (P = 0.006). The proportion of patients with complete or marked/moderate improvement in chest pain symptoms were significantly higher in patients with reflux (15/18, 83.3%) compared to those without (1/9, 11.1%) (P < 0.001).

CONCLUSION

The prevalence of gastroesophageal reflux disease in patients with 'non-cardiac chest pain' was high. The response to treatment with proton-pump inhibitors in patients with reflux disease, but not in those without, underlined the critical role of acid reflux in a subset of patients with 'non-cardiac chest pain'.

Neurophysiologic assessment of esophageal sensory processing in noncardiac chest pain

BACKGROUND & AIMS

Esophageal hypersensitivity is thought to be important in the generation and maintenance of symptoms in noncardiac chest pain (NCCP). In this study, we explored the neurophysiologic basis of esophageal hypersensitivity in a cohort of NCCP patients.

METHODS

We studied 12 healthy controls (9 women; mean age, 37.1 +/- 8.7 y) and 32 NCCP patients (23 women; mean age, 47.2 +/- 10 y). All had esophageal manometry, esophageal evoked potentials to electrical stimulation, and NCCP patients had 24-hour ambulatory pH testing.

RESULTS

The NCCP patients had reduced pain thresholds (PT) (72.1 +/- 19.4 vs 54.2 +/- 23.6, P = .02) and increased P1 latencies (P1 = 105.5 +/- 11.1 vs 118.1 +/- 23.4, P = .02). Subanalysis showed that the NCCP group could be divided into 3 distinct phenotypic classifications. Group 1 had reduced pain thresholds in conjunction with normal/reduced latency P1 latencies (n = 9). Group 2 had reduced pain thresholds in conjunction with increased (>2.5 SD) P1 latencies (n = 7), and group 3 had normal pain thresholds in conjunction with either normal (n = 10) or increased (>2.5 SD, n = 3) P1 latencies.

CONCLUSIONS

Normal esophageal evoked potential latencies with reduced PT, as seen in group 1 patients, is indicative of enhanced afferent transmission and therefore increased esophageal afferent pathway sensitivity. Increased esophageal evoked potential latencies with reduced PT in group 2 patients implies normal afferent transmission to the cortex but heightened secondary cortical processing of this information, most likely owing to psychologic factors such as hypervigilance. This study shows that NCCP patients with esophageal hypersensitivity may be subclassified into distinct phenotypic subclasses based on sensory responsiveness and objective neurophysiologic profiles.

The pathophysiology of non-cardiac chest pain

Various underlying mechanisms have been described in patients with non-cardiac chest pain (NCCP). By far, gastroesophageal reflux disease (GERD) is the most common cause and thus requires initial attention when patients with NCCP are managed. Esophageal dysmotility can be demonstrated in 30% of the NCCP patients, but appears to play a very limited role in symptom generation. A significant number of patients with NCCP lack any evidence of GERD and have been consistently shown to have reduced perception thresholds for pain. Peripheral and/or central sensitization have been suggested to be responsible for visceral hypersensivity in NCCP patients. Further understanding of the underlying mechanisms for pain in patients with NCCP will likely improve our current therapeutic approach.

Identification of the optimal parameters for recording cortical potentials evoked by mechanical stimulation of the human oesophagus

Cortical evoked potentials (CEP) have been recorded in response to both electrical stimulation (ES) and mechanical stimulation (MS) of the oesophagus. While the optimal parameters for recording reproducible oesophageal CEP to ES have recently been established, they have not yet been determined for MS, and reported CEP to MS show considerable variability. This study aimed to identify the optimal parameters required to record reproducible MS induced CEP. CEP were recorded from the vertex (Cz) in six subjects (one female; age range 23-47 years). MS was performed 5 cm above the lower oesophageal sphincter by rapidly inflating a 2-cm long silicone balloon at a frequency of 0.2 Hz. The rise time to maximum inflation was 165 ms. In order to determine the minimum number of stimuli required to produce optimal signal-to-noise quality, we acquired data in runs of 25, 50, 100 and 300 stimuli and to determine the stimulation intensity that produced the shortest latency and the largest amplitude CEP, we averaged four runs of 50 stimuli at five different intensities ranging from sensory threshold to pain. CEP reproducibility was then assessed in three subjects on three separate occasions using parameters determined from these measurements. We found that optimal signal-to-noise quality was achieved by averaging four runs of 50 stimuli; that P1 latency was shortest and P1-N1 amplitude largest at intensities of 75% and pain threshold and that highly reproducible CEP were obtained in all individuals. We conclude that it is possible to obtain highly reproducible oesophageal CEP to MS which can now be compared to those obtained by ES in order to identify which is most suitable for clinical studies.

Esophageal sensitivity and symptom perception in gastroesophageal reflux disease

Patients with gastroesophageal reflux disease (GERD) experience a wide spectrum of symptoms, varying both in quality and severity. This review summarizes clinical observations of esophageal sensitivity and symptom perception in GERD patients. The Bernstein test, although lacking standardization, remains a useful tool in determining esophageal sensitivity to acid stimuli. Ambulatory 24-hour pH monitoring with symptom event marking and subsequent symptom-reflux correlation between acid reflux events and esophageal symptomatology now provides an alternative method for establishing esophageal acid sensitivity. The intraesophageal balloon distention test (IEBD) was developed to assess esophageal sensitivity to mechanical stimuli. Variants of each of these tests have been applied to the evaluation of uncomplicated GERD patients and patients with esophagitis and Barrett's metaplasia, who generally demonstrate less esophageal sensitivity than the former group. Studies using these methods have demonstrated increased esophageal sensitivity in patients with esophageal chest pain and have also identified a subset of patients with esophageal symptoms yet normal esophageal acid exposure, a condition referred to as "hypersensitive esophagus." The Bernstein test, 24-hour pH monitoring with symptom assessment, and IEBD have each contributed to our understanding of esophageal pain syndromes; it is hoped that future work in this area will lead to improved and more specific therapy for these patients.

Treatment of symptomatic nonachalasia esophageal motor disorders with botulinum toxin injection at the lower esophageal sphincter

The purpose of this study was to determine if botulinum toxin injection at the lower esophageal sphincter improves symptoms in patients with nonachalasia spastic esophageal motility disorders. Fifteen patients with nonachalasia spastic esophageal motility disorders (diffuse esophageal spasm, nonspecific esophageal motility disorders, and lower esophageal sphincter dysfunction) unresponsive to medical therapy underwent endoscopic injection of botulinum toxin at the level of the gastroesophageal junction. Symptoms were scored (0 = no symptoms, 1 = mild, 2 = moderate, 3 = severe and 4 = very severe) before treatment, at seven days and every 30 days after treatment. There was significant improvement in chest pain, dysphagia, and regurgitation at 7,30,60 and 90 days after treatment. At one month after treatment, 11 of 15 (73%) patients had a good or excellent response to treatment. At the last patient interview (mean follow-up of 10.6 months), five (33%) patients continued to have a good to excellent response, whereas 10 (67%) underwent subsequent treatment with repeat botulinum toxin, pneumatic dilation, or bougienage. We conclude that botulinum toxin injection at the gastroesophageal junction leads to significant symptom improvement in patients with nonachalasia esophageal motility disorders. These results suggest that botulinum toxin may be an effective treatment option in some of these patients not responsive to conventional medical therapy.

Oesophageal sensation assessed by electrical stimuli and brain evoked potentials--a new model for visceral nociception

Sensory thresholds and brain evoked potentials were determined in 12 healthy volunteers using electrical stimulation of the oesophagus 28 and 38 cm from the nares. The peaks of the evoked potentials were designated N for negative deflections and P for positive. Continuous electrical stimulation (40 Hz) at the 38 cm position resembled heartburn (five of 12 subjects) while non-specific ('electrical') sensations were provoked at 28 cm (10 of 12). Thresholds of sensation and of pain were lower at the initial than the second determination, but did not differ with respect to stimulation site. The pain summation threshold to repeated stimuli (2 Hz, 5 stimuli) was determined for the first time in a viscus. This threshold was lower than the pain threshold to single stimuli at 38 cm (p < 0.02). Evoked potential latencies did not change significantly over a six month period while the N1/P2 amplitude was higher at the first measurement (p < 0.05). P1 and N1 latencies were significantly shorter 38 cm (medians 100 and 141 ms) than 28 cm from the nares (102 and 148 ms) (p = 0.04 and p = 0.008). Electrical stimulation of the oesophagus may serve as a human experimental model for visceral pain. Longer evoked potential latencies from the proximal compared with distal stimulations provide new information about the sensory pathways of the oesophagus.