Chicago classification version 4.0© technical review: Update on standard high-resolution manometry protocol for the assessment of esophageal motility

Abstract

The Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). A key feature of CCv.4.0 is the more rigorous and expansive protocol that incorporates single wet swallows acquired in different positions (supine, upright) and provocative testing, including multiple rapid swallows and rapid drink challenge. Additionally, solid bolus swallows, solid test meal, and/or pharmacologic provocation can be used to identify clinically relevant motility disorders and other conditions (eg, rumination) that occur during and after meals. The acquisition and analysis for performing these tests and the evidence supporting their inclusion in the Chicago Classification protocol is detailed in this technical review. Provocative tests are designed to increase the diagnostic sensitivity and specificity of HRM studies for disorders of esophageal motility. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification, decrease the proportion of HRM studies that deliver inconclusive diagnoses and increase the number of patients with a clinically relevant diagnosis that can direct effective therapy. Another aim in establishing a standard manometry protocol for motility laboratories around the world is to facilitate procedural consistency, improve diagnostic reliability, and promote collaborative research.

FIGURE 1

Effect of position on esophageal motility in a healthy subject. The esophageal contraction tends to be slower, better coordinated and more vigorous in the supine (left panels) than the upright, seated (right panels) position. As a consequence, the proportion of ineffective, hypotensive contractions is often higher in the upright position. Appropriate normative values must be applied. Image Courtesy of Digestive Function: Basel at Klinik Arlesheim

FIGURE 2

EGJ outflow obstruction with IRP >15 mm Hg is more frequently observed with wet swallows in the supine, than the upright position. Many such cases are artefactual, are not associated with increased intra-bolus pressure and are related to pressure on individual sensors as the catheter passes through the EGJ. If discordant findings are present, then provocative tests are helpful to identify individuals with clinically relevant disease. Image courtesy of Oesophageal Laboratory, University College London

FIGURE 3

Multiple Rapid Swallows (MRS) is a physiological test that increases deglutitive inhibition of the esophageal contration and EGJ by asking the subject to swallow five times in quick succession. Subsequently, in healthy subjects, the MRS post-contraction is often augmented (more vigorous than normal). MRS highlights failure of deglutitive inhibition in patients with achalasia, esophageal spasm and hypercontractile disorders. Additionally, the lack of augmentation in the post-MRS contraction can indicate a lack of contractile reserve (ie, ability to respond to physiological or iatrogenic challenge). Image courtesy of Digestive Function: Basel at Klinik Arlesheim

FIGURE 4

Rapid Drink Challenge (RDC) is performed by asking the subject to drink a large volume of water (100–200 ml) by a series of swallows. The rate can be controlled by drinking through a straw. In healthy subjects, similar to MRS, RDC highlights deglutitive inhibition during repeated swallows (upper panel). Additionally, the presence of a normal contraction sequence following the RDC is a specific marker of normal contractility; however, this is not observed in all healthy controls. Rapid Drink Challenge (RDC) highlights failure of deglutitive inhibition in patients with achalasia (lower panel). In this case the patient had inconclusive findings with normal IRP during wet swallows (left panel). RDC revealed conclusive evidence of achalasia with pan-esophageal pressurization and IRP >50 mm Hg. The patient responded to pneumatic dilatation. Images courtesy of Functional GI Laboratory, Zürich University Hospital.

FIGURE 5

Effect of bolus consistency on esophageal motility in a healthy subject. The esophageal contraction tends to be faster (shorter distal latency), less well coordinated (larger break in contractile front) and less vigorous (lower DCI) in wet swallows (left panel) than solid swallows (right panel). Additionally the IRP is increased for solid swallows due to higher viscous resistance to bolus passage through the EGJ. Appropriate normative values must be applied. Solid swallows can augment peristaltic motility in health and, as in the case presented, demonstrate contractile reserve in patients with ineffective motility during water swallows. Image courtesy of Oesophageal Laboratory, University College London.

FIGURE 6

Representative excerpt from HRM recording of a solid test meal ingested by a normal, healthy subject. Image Courtesy of Digestive Function: Basel at Klinik Arlesheim

FIGURE 7

Water swallows (left panel) and start of solid test meal (right panel) in a patient with dysphagia for solids and normal endoscopy. The inclusion of solid swallows increases diagnostic sensitivity for motility disorders especially, as in this case, EGJ outflow obstruction. Additionally, the close temporal association of abnormal motility with symptoms supports the clinical relevance of the finding. Image Courtesy of Digestive Function: Basel at Klinik Arlesheim

FIGURE 8

Post-prandial observation with combined high-resolution impedance manometry can identify the causes of symptoms that occur after meals. Transient LES relaxations (TLESRs) are often observed, however, a high frequency of these events after meals is consistent with the diagnosis of gastro-oesophageal reflux disease. In this case of a patient with volume regurgitation after meals, reflux and belching were associated with TLESRs; however, repetitive volume regurgitation was caused by rumination. This was confirmed by the presence of rapid increase in gastric pressure (>25 mm Hg) coincident with LES and UES relaxation and immediately followed by typical symptoms. Image courtesy of Digestive Function: Basel at Klinik Arlesheim

FIGURE 9

Two alternate algorithms to guide the use of provocative tests during the CCv4.0 Protocol are provided. Left panel: Protocol commencing with wet swallows in the supine position. Right panel: Protocol commencing with wet swallows in the upright position. In both provocative tests that increase the sensitivity and specificity for detection of clinically relevant esophageal motility disorders are recommended.