Machine Learning Clustering Identifies Achalasia-Spectrum Phenotypes in Distal Esophageal Spasm.

Diagnose non-achalasia esophageal motility disorders on high-resolution manometry performed with the full CCv4.0 protocol, and treat the manometric pattern as a disorder only when it is accompanied by clinically relevant symptoms. The protocol requires both positions: supine (60-second adaptation, 30-second landmark/baseline, ten 5 mL wet swallows, one multiple rapid swallow of five 2 mL swallows at 2-3 second intervals) and upright at >=80 degrees (five 5 mL wet swallows plus a 200 mL rapid drink challenge); solid swallows, a solid test meal, or pharmacologic provocation (amyl nitrite, cholecystokinin) are added when standard swallows do not explain the symptom. IRP thresholds are manufacturer- and position-specific (for the Medtronic system, abnormal median IRP is >=15 mmHg supine and >=12 mmHg upright). CCv4.0 grades diagnoses as conclusive or inconclusive: distal esophageal spasm requires a normal median IRP plus >=20% premature contractions (distal latency <4.5 s with DCI >=450 mmHg*s*cm) AND clinically relevant dysphagia or non-cardiac chest pain; hypercontractile esophagus requires a normal median IRP plus >=20% hypercontractile supine swallows (DCI >8,000 mmHg*s*cm) AND clinically relevant dysphagia or non-cardiac chest pain, with mechanical obstruction excluded. Ineffective esophageal motility requires a normal IRP in both positions plus >70% ineffective swallows or >=50% failed peristalsis, where an ineffective swallow is weak (DCI 100-450), failed (DCI <100), or fragmented; 50-70% ineffective swallows is inconclusive and requires supportive testing. Absent contractility requires a normal median IRP in both supine and upright positions with 100% failed peristalsis, and because achalasia can present this way, provocative testing and adjunctive investigation are needed when there is any clinical suspicion of achalasia. Manometric EGJ outflow obstruction is never conclusive on manometry alone: it requires an elevated median IRP in BOTH the primary and secondary position plus >=20% of swallows with elevated intrabolus pressure, with peristalsis preserved; a conclusive, clinically relevant diagnosis additionally requires compatible symptoms (dysphagia or non-cardiac chest pain) AND at least one supportive investigation showing obstruction (timed barium esophagram with tablet and/or functional lumen imaging probe). An isolated elevated supine IRP, an isolated elevated upright IRP, or isolated elevated intrabolus pressure alone are each inconclusive and do not establish EGJOO. CCv4.0 is a diagnostic classification and does not issue treatment recommendations; therapy for these entities is not traceable to this document.