Subtype of Achalasia and Integrated Relaxation Pressure Measured Using the Starlet High-resolution Manometry System: A Multicenter Study in Japan

Background/Aims ManoScan and Sandhill high-resolution manometry (HRM) systems are used worldwide; however, the diagnosis of achalasia on the Starlet HRM system is not fully characterized. Furthermore, the impact of calcium channel blockers and nitrites in treating achalasia has not been investigated using HRM. Management of recurrent cases is a priority issue, although few studies have examined patient characteristics. Methods We conducted a multicenter, large-scale database analysis. First, the diagnosis of treatment-naive achalasia in each HRM system was investigated. Next, patient characteristics were compared between type I-III achalasia, and the impact of patient characteristics, including calcium channel blocker and nitrite use for integrated relaxation pressure (IRP) values, were analyzed. Finally, patient characteristics with recurrent achalasia were elucidated. Results The frequency of type I achalasia with Starlet was significantly higher than that with ManoScan and Sandhill HRM systems. In achalasia, multivariate analysis identified male sex, advanced age, long disease duration, obesity, type I achalasia, and sigmoid type as risk factors related to normal IRP values (< 26 mmHg). Calcium channel blockers and nitrites use had no significant impact on the IRP values, although achalasia symptoms were indicated to be alleviated. In recurrent cases, the IRP value was significantly lower, and advanced age, long disease duration, and sigmoid type were more common than in treatment-naive patients. Conclusions We should cautiously interpret the type of achalasia and IRP values in the Starlet HRM system. Symptoms of recurrent cases are related to disease progression rather than IRP values, which should be considered in decision making.