Is integrated relaxation pressure a promising predictor of effectiveness of peroral endoscopic myotomy for achalasia?

BACKGROUND

Peroral endoscopic myotomy (POEM), first introduced in 2010, appears to be an effective therapy with few complications. This study aimed to find an optimal predictor of POEM outcome in achalasia.

METHODS

We retrospectively assessed 89 patients diagnosed with achalasia who underwent POEM in General Hospital of Tianjin Medical University, from September 2012 to March 2015. Associations of Eckardt score with symptom duration, lower esophageal resting pressure, 4-second integrated relaxation pressure (4s-IRP), and maximum esophageal diameter were assessed before POEM. The most relevant data were progressively grouped to compare symptom improvement after POEM in 85 patients at 1 year follow-up.

RESULTS

The most significant correlation was found between 4s-IRP and Eckardt score (p < 0.01). The 85 achalasia patients (1-year follow-up after POEM) were divided into 3 groups according to 4s-IRP values; patients with mean 4s-IRP of 25 - 34 mmHg exhibited significantly greater improvement of clinical symptoms compared with the remaining 2 groups (p < 0.05). No significant postoperative difference was noted between types I and II in all patients according to Chicago classification criteria. The 40 patients with 4s-IRP of 25 - 34 mmHg were further divided into 2 subgroups; the 28 patients with type II achalasia responded better to POEM than the 12 with type I disease (p < 0.05).

CONCLUSIONS

4s-IRP, together with achalasia subtypes, may predict treatment outcome after POEM. Patients with type II achalasia and 4s-IRP of 25 - 34 mmHg may experience more satisfactory remission after POEM.