Esophageal Manometry Interpretation Guidelines

Pre-Interpretation Requirements

• The American Gastroenterological Association recommends that endoscopy with biopsies should be performed first to exclude structural causes like strictures and eosinophilic esophagitis, and that patients should fast appropriately, with motility-affecting medications stopped 48 hours prior 1, 2
• The American Gastroenterological Association suggests that catheter-specific normal values should be used, as values differ significantly between manufacturers 3

Step 1: Assess LES Function

• The American College of Gastroenterology recommends evaluating the integrated relaxation pressure (IRP) to assess lower esophageal sphincter (LES) function, with IRP >15 mm Hg (Manoscan) or >25 mm Hg (Unisensor) indicating impaired LES relaxation and suggesting achalasia or esophagogastric junction (EGJ) outflow obstruction 4, 3
• The American College of Gastroenterology suggests classifying achalasia subtype based on esophageal body pressurization patterns, with Type I (Classic) having no pressurization, absent peristalsis 4
• The American College of Gastroenterology recommends that normal IRP with normal peristalsis rules out achalasia, which is the most critical distinction as missing achalasia before antireflux surgery is catastrophic 5

Step 2: Evaluate Esophageal Body Peristalsis

• The American Gastroenterological Association recommends assessing the distal contractile integral (DCI) to quantify contraction vigor, with DCI <450 mm Hg·s·cm indicating weak/failed peristalsis, DCI 450-8000 mm Hg·s·cm indicating normal peristalsis, and DCI >8000 mm Hg·s·cm indicating hypercontractile esophagus (Jackhammer esophagus) 4, 2
• The American Gastroenterological Association suggests measuring distal latency (DL) from UOS relaxation to contractile deceleration point, with DL <4.5 seconds indicating premature contractions and distal esophageal spasm 4, 2

Step 3: Apply Chicago Classification Hierarchy

• The American College of Gastroenterology recommends applying the Chicago Classification hierarchy to categorize findings into achalasia subtypes, major motility disorders, or minor peristaltic abnormalities, with major motility disorders taking diagnostic precedence 4, 1
• The American College of Gastroenterology suggests that achalasia (Types I, II, III) is characterized by elevated IRP with absent/abnormal peristalsis, EGJ outflow obstruction is characterized by elevated IRP with some preserved peristalsis, and distal esophageal spasm is characterized by ≥20% premature contractions (DL <4.5s) with normal IRP 4, 2

Step 4: Perform Adjunctive Testing When Standard Swallows Are Inconclusive

• The American Gastroenterological Association recommends performing provocative maneuvers, such as rapid drink challenge (RDC) or multiple rapid swallows (MRS), to assess peristaltic reserve when standard swallows are inconclusive 2, 3
• The American Gastroenterological Association suggests that a test meal can be valuable when dysphagia persists despite normal water swallows, as it can change clinical diagnosis and better predict 2-year outcomes 2

Step 5: Integrate Clinical Context

• The American College of Gastroenterology recommends that manometry findings must correlate with symptoms, and that minor motility disorders have uncertain clinical significance, with 70% of patients being asymptomatic at 5-year follow-up 2
• The American College of Gastroenterology suggests that dysphagia, chest pain, hoarseness, vomiting, and weight loss have high specificity for esophageal motility disorders, while regurgitation and heartburn alone have poor accuracy for distinguishing motility disorders from reflux 2

Critical Pitfalls to Avoid

• The American Gastroenterological Association recommends avoiding the diagnosis of GERD with manometry, as manometry cannot confirm or exclude reflux disease, and instead using pH or impedance-pH monitoring 4, 5
• The American Gastroenterological Association suggests avoiding the use of manometry as the initial test for chest pain, as cardiac causes must be excluded first, followed by endoscopy and empiric PPI trial before manometry 4
• The American Gastroenterological Association recommends recognizing position-dependent differences, with upright studies yielding different normal values than supine studies, particularly for solid-state catheters 1, 3

Esophageal Manometry Indications and Guidelines

Clear Indications for Manometry

• Manometry is indicated to establish the diagnosis of dysphagia when mechanical obstruction cannot be found on endoscopy or barium studies, particularly to diagnose achalasia, as recommended by the American Gastroenterological Association 6, 7, 8, 9, 10, 11, 12, 13
• Manometry is indicated for proper placement of intraluminal devices when positioning depends on functional landmarks like the lower esophageal sphincter 6, 7, 8, 9, 10, 11, 12, 13
• Manometry is indicated before antireflux surgery if there is any question of an alternative diagnosis, especially achalasia, to prevent catastrophic outcomes if fundoplication is performed on a patient with achalasia 6, 7, 8, 9, 10, 11, 12, 13

Possible Indications

• Manometry is possibly indicated for preoperative assessment of peristaltic function in all patients being considered for antireflux surgery, though this is not an absolute requirement, as suggested by guidelines from the American College of Gastroenterology 6, 7, 8, 9, 10, 11, 12, 13
• Manometry is possibly indicated to assess dysphagia symptoms in patients who have undergone either antireflux surgery or treatment for achalasia 6, 7, 8, 9, 10, 11, 12, 13

Clinical Algorithm for Appropriate Use

• For dysphagia patients, the American Gastroenterological Association recommends first performing endoscopy with biopsies to exclude structural abnormalities, then considering barium esophagram, and finally proceeding to manometry if structural causes are excluded and functional disorder is suspected, particularly achalasia 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
• For chest pain patients, guidelines suggest ruling out cardiac causes, performing endoscopy with esophageal biopsies, trial empiric PPI therapy, and considering pH or impedance-pH monitoring before manometry, as recommended by the American College of Cardiology and the American Gastroenterological Association 6, 7, 8, 9, 10, 11, 12, 13, 16

High‑Resolution Manometry Is the Gold‑Standard Diagnostic Test for Achalasia

Diagnostic Criteria and Guideline Recommendations

• The American Gastroenterological Association (AGA) states that esophageal manometry is required to establish a diagnosis of dysphagia when no mechanical obstruction is identified, especially when achalasia is suspected. 17
• High‑resolution manometry (HRM) is the definitive test for achalasia because it demonstrates the two cardinal physiologic abnormalities: (1) impaired deglutitive lower esophageal sphincter (LES) relaxation with an integrated relaxation pressure > 15 mm Hg, and (2) absent esophageal body peristalsis. 18
• The 2024 AGA guidelines designate HRM as essential not only for confirming achalasia but also for classifying the disorder into Chicago Classification subtypes (I, II, III), which guides phenotype‑directed therapy and improves outcomes. 19

Role of Complementary Imaging

• A timed barium esophagram may reveal delayed barium clearance and structural changes suggestive of achalasia, but it cannot confirm the diagnosis; it should be performed alongside HRM as a complementary study. 19, 20

Tests That Do Not Diagnose Achalasia

• Conventional upper endoscopy (EGD) can show indirect signs (e.g., retained secretions, puckered gastro‑esophageal junction) but cannot confirm achalasia because it does not assess motility. 19
• Endoscopic ultrasound (EUS) has no role in primary achalasia diagnosis; it is reserved for evaluating esophagogastric junction outflow obstruction when pseudo‑achalasia from infiltrative disease or malignancy is a concern. 18, 21
• Esophageal pH monitoring is not indicated for diagnosing achalasia; the AGA specifies that pH testing should not be used to diagnose motility disorders, and conversely, manometry should not be used to diagnose gastro‑esophageal reflux disease. 17

Clinical Management Algorithm

• Step 1: Perform high‑resolution esophageal manometry to assess for achalasia or other major motility disorders. 19
• Step 2: Obtain a timed barium esophagram concurrently to evaluate structural outflow obstruction. 19
• Step 3: Consider functional luminal imaging probe (FLIP) as an adjunct if manometric findings are equivocal. 19

Safety Considerations

• Performing antireflux (fundoplication) surgery without prior manometry to exclude achalasia can lead to catastrophic outcomes; the AGA mandates mandatory manometric evaluation before antireflux surgery when an alternative diagnosis such as achalasia is possible. 17, 21