New technologies in the gastrointestinal clinic and research: Impedance and high-resolution manometry

Table 1 Classification of individual swallows based on pressure topography criteria

Classification	Criteria
EGJ Deglutitive Relaxation (referenced to gastric pressure)
Normal relaxation	4 s Integrated Relaxation Pressure (IRP) < 15 mmHg
Impaired relaxation	4 s IRP >= 15 mmHg
Distal Segment Contraction (referenced to gastric pressure)
Normal	<= 2 cm defect in the 30 mmHg isobaric contour, Contractile Front Velocity (CFV) < 8 cm/s, Intrabolus Pressure (IBP) < 15 mmHg, and Distal Contractile Integral (DCI) < 5000 mmHg × s × cm
Mild peristaltic defect	Normal appearing wavefront propagation with a 2-5 cm defect in the 30 mmHg isobaric contour
Severe peristaltic defect	Evidence of wavefront propagation with a >= 5 cm defect in the 30 mmHg isobaric contour
Absent peristalsis	No propagating contractile wavefront and minimal (< 3 cm) contractile activity or pressurization greater than the 30 mmHg IBC
Nutcracker	DCI > 5000 and < 8000 mmHg × s × cm
Spastic nutcracker	DCI > 8000 mmHg × s × cm
Spasm	Simultaneous contraction (CFV > 7.5 cm/s)
Elevated intrabolus pressure	IBP > 15 mmHg compartmentalized between the EGJ and the peristaltic wavefront
Panesophageal pressurization	Esophageal pressurization UES to EGJ with > 30 mmHg IBP

Table 2 Distal esophageal motility disorders based on pressure topography criteria

Disorder	Criteria
With Normal EGJ Relaxation (mean IRP < 15 mmHg)
Peristaltic Weakness
Intermediate	More than 30% of swallows with mild or severe peristaltic defects, but numerically insufficient to constitute severe peristaltic weakness
Severe	>= 70% of swallows with severe peristaltic defects
Aperistalsis	100% swallows with absent peristalsis
Nutcracker Esophagus	Normal CFV, Mean DCI > 5000 and < 8000 mmHg × s × cm, can be localized to either distal subsegment or LES
Spastic Nutcracker	Normal CFV, Mean DCI > 8000 mmHg × s × cm
Distal Esophageal Spasm	Normal EGJ relaxation and spasm (CFV > 8 cm/s) with >= 20% of swallows
Esophageal Obstruction	Increased IBP or panesophageal pressurization not associated with EGJ obstruction
With Impaired EGJ Relaxation (mean IRP >= 15 mmHg)
Achalasia
Classic achalasia	Impaired EGJ relaxation and aperistalsis
Achalasia with esophageal compression	Impaired EGJ relaxation, aperistalsis, and panesophageal pressurization with >= 20% of swallows
Spastic achalasia	Impaired EGJ relaxation, aperistalsis, and spasm with >= 20% of swallows
EGJ Obstruction
Mild	Elevated IBP (15-30 mmHg) that is compartmentalized between the peristaltic wavefront (normal, weak, or nutcracker) and EGJ
Severe	IBP > 30 mmHg that is compartmentalized between the peristaltic wavefront (normal or nutcracker) and EGJ