Do the Data Support Manometric Subclassifications for Ineffective Esophageal Motility?

We read the article by Hiestand et al.[1] entitled, “Manometric Subtypes of Ineffective Esophageal Motility” with great interest. The authors have presented subclassification for the manometric diagnosis of ineffective esophageal motility (IEM) which is defined as ≥50% ineffective swallows.[2] Authors have subclassified IEM into more severe IEM-Persistens (IEM-P) and less severe IEM-Alternans (IEM-A) depending on presence of no normal swallows (IEM-P) vs. some normal swallows (IEM-A).

Authors showed that there is an increased distal esophageal acid exposure, weaker lower esophageal sphincter (LES), and lesser response to proton pump inhibitors (PPI) as measured by the degree of gastric acid suppression in patients with IEM-P. They go on to state that these are due to the more advanced disease state of dysmotility.

We are not sure how degree of acid suppression in the stomach can be physiologically related to esophageal motor activity. The pH study was done on PPI in 85% of included subjects. While authors have used separate criteria to define positive study in such patients, the number of such patients should be mentioned and compared for individual subtypes, as inadequate acid suppression can be related to the pH-study results. Further, the authors are implying that the same pathophysiological causes of decreased motility (IEM-P>IEM-A) are also leading to a worsening function of LES resting pressure (LESP)—while they themselves show that there is no difference in motility related issues (e.g. impaired bolus transit: 62% in IEM-A and 58% in IEM-P) or prevalence of connective tissue disorders. Mean LESP was significantly lower in IEM-P vs. IEM-A. The authors should discuss and compare the rate of hiatal hernia among 17/36 IEM-P and 129/195 IEM-A patients with available reflux study rather than the overall groups to see its correlation with reflux. Hiatal hernia and/or weak LES are known to be related to reflux, independent of body motility, and can be major confounding factors in the present study.[3, 4] We believe the conclusion that IEM-P is advanced IEM-A is not adequately supported by the data presented.