Fig. 1

Typical pictures of three types of HRM classification before and after stent treatment. A Type I achalasia before treatment, no esophageal contraction and no esophageal pressurization. B Type II achalasia before treatment, is characterized by panesophageal pressurization and absence of a peristaltic contraction. C Type III achalasia before treatment, there are at least 20% premature contractions, defined as DL < 4.5 s. D Type I achalasia after treatment, low esophageal pressure decrease after stent insertion for 1 month and removed. E Type II achalasia after treatment, panesophageal pressure reduced, peristaltic contraction appeared. F Type III achalasia after stent treatment, Spastic hypertension disappeared