Achalasia diagnosed despite normal integrated relaxation pressure responds favorably to therapy

Background: Achalasia diagnosis requires elevated integrated relaxation pressure (IRP; manometric marker of lower esophageal sphincter [LES] relaxation). Yet, some patients exhibit clinical features of achalasia despite normal IRP and have LES dysfunction demonstrable by other means. We hypothesized these patients to exhibit equivalent therapeutic response compared to standard achalasia patients.

Methods: Symptomatic achalasia-like cases, despite normal IRP, displayed evidence of impaired LES relaxation using rapid drink challenge (RDC), solid swallows during high-resolution manometry, and/or barium esophagogram; were treated with achalasia therapies and compared to standard achalasia patients with raised IRP. Outcomes included equivalence for short- and long-term symptom response and stasis on barium esophagogram.

Key results: Twenty-nine normal IRP achalasia cases (14 males, median age 50 year, median Eckardt 6, barium stasis 12 ± 7 cm) and 29 consecutive standard achalasia controls underwent therapy. Among cases, LES dysfunction was most often identified by RDC and/or barium esophagogram. Short-term symptomatic success was equivalent in cases vs controls (90% vs 93%; 95% CI for difference: -19% to 13%). Median short-term (1 vs 1; 95% CI for difference: 0-1) and long-term Eckardt scores (2 vs 1; 95% CI for difference: 0-2) were similar in cases and controls, respectively. Adequate clearance was observed in 67% of cases vs 81% of controls on post-therapy esophagogram.

Conclusions and inferences: We described a subset of achalasia patients with normal IRP, but impaired LES relaxation identifiable only on additional provocative tests. These patients benefited from treatment, suggesting that such tests should be performed to increase the number of clinically relevant diagnoses.