How do I interpret esophageal manometry results?

How to Interpret Esophageal Manometry Results

Interpret esophageal manometry systematically by first assessing lower esophageal sphincter (LES) function using integrated relaxation pressure (IRP), then evaluating esophageal body peristalsis using distal contractile integral (DCI) and contractile patterns, and finally applying the Chicago Classification to categorize findings into achalasia subtypes, major motility disorders, or minor peristaltic abnormalities. 1

Pre-Interpretation Requirements

Before interpreting manometry results, confirm that:

• Endoscopy with biopsies was performed first to exclude structural causes like strictures and eosinophilic esophagitis 1
• Patients fasted appropriately (6 hours standard, 12 hours if achalasia suspected with retained food at endoscopy) 1
• Motility-affecting medications were stopped 48 hours prior (nitrates, calcium channel blockers) 1
• Catheter-specific normal values are used, as values differ significantly between manufacturers (Manoscan vs Unisensor vs water-perfused systems) 1

Step 1: Assess LES Function (Rule Out Achalasia First)

Start by evaluating the integrated relaxation pressure (IRP), which measures LES relaxation during swallowing 1:

• IRP >15 mm Hg (Manoscan) or >25 mm Hg (Unisensor) indicates impaired LES relaxation and suggests achalasia or esophagogastric junction (EGJ) outflow obstruction 1
• Normal IRP with normal peristalsis rules out achalasia—this is the most critical distinction as missing achalasia before antireflux surgery is catastrophic 1, 2

If IRP is elevated, classify achalasia subtype based on esophageal body pressurization patterns 1:

• Type I (Classic): No pressurization, absent peristalsis
• Type II (Compression): Panesophageal pressurization (best prognosis)
• Type III (Spastic): Premature/spastic contractions with elevated IRP

Step 2: Evaluate Esophageal Body Peristalsis

Assess the distal contractile integral (DCI), which quantifies contraction vigor (amplitude × duration × length) 1:

• DCI <450 mm Hg·s·cm: Weak/failed peristalsis
• DCI 450-8000 mm Hg·s·cm: Normal peristalsis
• DCI >8000 mm Hg·s·cm: Hypercontractile esophagus (Jackhammer esophagus) 1

Measure distal latency (DL) from UOS relaxation to contractile deceleration point 1:

• DL <4.5 seconds: Premature contractions indicating distal esophageal spasm 1
• DL ≥4.5 seconds: Normal propagation velocity

Identify peristaltic breaks (gaps >5 cm in the 20 mm Hg isobaric contour) 1:

• Large breaks (>5 cm) in >50% of swallows: Fragmented peristalsis
• Failed peristalsis (DCI <450) in >50% of swallows: Ineffective esophageal motility

Step 3: Apply Chicago Classification Hierarchy

Major motility disorders (these take diagnostic precedence) 1:

1. Achalasia (Types I, II, III): Elevated IRP with absent/abnormal peristalsis
2. EGJ outflow obstruction: Elevated IRP with some preserved peristalsis
3. Distal esophageal spasm: ≥20% premature contractions (DL <4.5s) with normal IRP
4. Hypercontractile esophagus: ≥20% swallows with DCI >8000 mm Hg·s·cm
5. Absent contractility: 100% failed peristalsis with normal IRP

Minor motility disorders (diagnose only if no major disorder present) 1:

• Ineffective esophageal motility: >50% ineffective swallows (DCI <450 or large breaks)
• Fragmented peristalsis: >50% swallows with breaks >5 cm but DCI >450

Step 4: Perform Adjunctive Testing When Standard Swallows Are Inconclusive

If 10 standard 5-mL water swallows show minor abnormalities or are equivocal, perform provocative maneuvers to assess peristaltic reserve 1:

• Rapid drink challenge (RDC): 200 mL water drunk freely in upright position—normal response shows sustained esophageal contraction with IRP <15 mm Hg 1
• Multiple rapid swallows (MRS): 2 mL water every few seconds—normal response shows peristaltic inhibition during swallows followed by strong contraction 1
• Solid/viscous swallows or test meal: More physiologic than water, doubles diagnostic yield by unmasking pathology not seen with water alone 1

A test meal is particularly valuable when dysphagia persists despite normal water swallows, as it changed clinical diagnosis in 39% of patients and better predicted 2-year outcomes 1

Step 5: Integrate Clinical Context

Manometry findings must correlate with symptoms 3:

• Dysphagia, chest pain, hoarseness, vomiting, and weight loss have high specificity for esophageal motility disorders 3
• Regurgitation and heartburn alone have poor accuracy for distinguishing motility disorders from reflux 3
• Minor motility disorders have uncertain clinical significance—70% of patients are asymptomatic at 5-year follow-up, indicating good prognosis 1

Critical Pitfalls to Avoid

Do not diagnose GERD with manometry—manometry cannot confirm or exclude reflux disease 1, 2. Use pH or impedance-pH monitoring instead 1.

Do not use manometry as the initial test for chest pain—cardiac causes must be excluded first, followed by endoscopy and empiric PPI trial before manometry 2

Do not rely on endoscopic appearance to assess LES function—there is 58% discordance between endoscopic findings and manometric LES measurements 1, 4

Do not over-interpret minor motility disorders from water swallows alone—these findings often normalize with provocative testing or solid swallows and rarely progress over time 1

Recognize position-dependent differences—upright studies (more physiologic) yield different normal values than supine studies, particularly for solid-state catheters 1

Special Clinical Scenarios

Before antireflux surgery: Manometry is mandatory to exclude achalasia (performing fundoplication on achalasia is catastrophic) and strongly recommended to document peristaltic function 1, 2

After antireflux surgery with dysphagia: High-resolution manometry provides useful diagnostic information not obtainable by standard manometry, particularly when combined with test meals (diagnostic yield increases from 30% to 70% for dysmotility) 1

For pH probe placement: Manometry is the preferred method to localize the LES, with the pH probe placed 5 cm above the manometrically determined upper LES border 1

Eosinophilic esophagitis: Manometry does not provide diagnostic value—diagnosis requires endoscopy with biopsies 1