Diagnostic evaluation in patients with suspected achalasia

EUS: endoscopic ultrasound; FLIP: functional lumen imaging probe; FNA: fine needle aspiration; IRP: integrated relaxation pressure; LES: lower esophageal sphincter.

* Diagnostic manometric findings of achalasia are incomplete relaxation of the LES (IRP above the upper limit of normal) and aperistalsis in the distal two-thirds of the esophagus.

¶ Equivocal manometric findings include incomplete LES relaxation but some preserved peristalsis; some complete LES relaxation with aperistalsis.

Δ FLIP uses high-resolution impedance planimetry during volume-controlled distension to measure esophageal cross-sectional area and distensibility (ie, cross-sectional area in relation to distension pressure). Refer to UpToDate content on FLIP for additional details.