What is the difference between EndoFLIP (Functional Lumen Imaging Probe) and esophageal manometry?

Differences Between EndoFLIP and Esophageal Manometry

EndoFLIP (Functional Lumen Imaging Probe) and esophageal manometry are complementary diagnostic tools that measure different aspects of esophageal function, with manometry measuring pressure and contractility while EndoFLIP measures distensibility and compliance.

Key Differences

Measurement Parameters

• Esophageal Manometry:

  • Measures pressure changes within the esophagus
  • Evaluates peristaltic contractions and sphincter function
  • Assesses contractility of the esophageal body
  • Quantifies lower esophageal sphincter (LES) pressure and relaxation 1

• EndoFLIP:

  • Measures esophageal distensibility and compliance
  • Uses impedance planimetry technology
  • Evaluates cross-sectional area at various locations
  • Assesses the tension-strain relationship of the esophagus 2

Technical Approach

• Esophageal Manometry:

  • Uses pressure sensors along a catheter
  • High-resolution manometry provides detailed pressure topography
  • Evaluates esophageal function during swallowing 1, 3

• EndoFLIP:

  • Uses a balloon catheter with impedance electrodes
  • Measures distensibility during controlled balloon inflation
  • Provides the distensibility index (DI) in mm²/mmHg 4, 5

Clinical Applications

Esophageal Manometry Indications

According to the American Gastroenterological Association guidelines 1:

1. Indicated for:

   • Establishing diagnosis of dysphagia when mechanical obstruction cannot be found
   • Placement of intraluminal devices (e.g., pH probes)
   • Preoperative assessment before antireflux surgery

2. Possibly indicated for:

   • Preoperative assessment of peristaltic function
   • Evaluation of dysphagia after antireflux surgery or achalasia treatment

3. Not indicated for:

   • Confirming GERD diagnosis
   • Initial test for chest pain or other esophageal symptoms

EndoFLIP Applications

1. Diagnostic uses:

   • Evaluating esophagogastric junction (EGJ) distensibility
   • Detecting achalasia with relatively low integrated relaxation pressure (IRP)
   • Assessing contractile activity of the esophageal body 2, 5

2. Therapeutic applications:

   • EsoFLIP (therapeutic version) for dilation in achalasia and EGJ outflow obstruction
   • Intraoperative assessment during myotomy or fundoplication 6

Clinical Relevance and Complementary Nature

• Diagnostic Enhancement:

  • EndoFLIP can detect abnormalities in patients with normal manometry findings
  • Particularly valuable in cases with borderline manometric values 2

• Treatment Planning:

  • Manometry helps classify motility disorders according to Chicago Classification
  • EndoFLIP provides additional information on wall compliance and distensibility
  • Combined use improves surgical planning for achalasia and GERD 3, 6

Normative Values and Interpretation

• Manometry:

  • Standardized parameters like integrated relaxation pressure (IRP)
  • Chicago Classification v4.0 includes provocative tests to improve diagnostic yield 2, 7

• EndoFLIP:

  • EGJ distensibility index (EGJ-DI) at 40-60ml distention
  • Values below 2 mm²/mmHg generally considered abnormal
  • 50-60ml distention volumes recommended for clinical practice 4

Common Pitfalls

• Manometry:

  • Inconsistency in IRP measurements
  • Limited ability to assess mechanical properties of the esophagus
  • May miss subtle abnormalities in distensibility 2

• EndoFLIP:

  • Lack of standardization in anesthetic use, probe placement, and inflation protocols
  • Limited normative data compared to manometry
  • Primarily focused on EGJ with less established role in other conditions 5

In clinical practice, these tools should be viewed as complementary rather than competitive, with each providing unique insights into esophageal function and pathology.