Achalasia: a new clinically relevant classification by high-resolution manometry

Abstract

Background & aims: Although the diagnosis of achalasia hinges on demonstrating impaired esophagogastric junction (EGJ) relaxation and aperistalsis, 3 distinct patterns of aperistalsis are discernable with high-resolution manometry (HRM). This study aimed to compare the clinical characteristics and treatment response of these 3 subtypes.

Methods: One thousand clinical HRM studies were reviewed, and 213 patients with impaired EGJ relaxation were identified. These were categorized into 4 groups: achalasia with minimal esophageal pressurization (type I, classic), achalasia with esophageal compression (type II), achalasia with spasm (type III), and functional obstruction with some preserved peristalsis. Clinical and manometric variables including treatment response were compared among the 3 achalasia subtypes. Logistic regression analysis was performed using treatment success as the dichotomous dependent variable controlling for independent manometric and clinical variables.

Results: Ninety-nine patients were newly diagnosed with achalasia (21 type I, 49 type II, 29 type III), and 83 of these had sufficient follow-up to analyze treatment response. Type II patients were significantly more likely to respond to any therapy (BoTox [71%], pneumatic dilation [91%], or Heller myotomy [100%]) than type I (56% overall) or type III (29% overall) patients. Logistic regression analysis found type II to be a predictor of positive treatment response, whereas type III and pretreatment esophageal dilatation were predictive of negative treatment response.

Conclusions: Achalasia can be categorized into 3 subtypes that are distinct in terms of their responsiveness to medical or surgical therapies. Utilizing these subclassifications would likely strengthen future prospective studies of treatment efficacy in achalasia.

Figure 1

Methodology for using the isobaric contour tool to determine the 4-second IRP and the PFV. The pressure highlighted by the isobaric contour tool is progressively increased during analysis until it excludes a period of 4 seconds from the pressure domain of the EGJ. That value is equal to the 4-second IRP and, in this example, is equal to 10 mm Hg because the 3 segments (white bars) define a cumulative period of time of 4 seconds during which the pressure is less than 10 mm Hg (solid isobaric line). The PFV is illustrated using a second isobaric contour with a setting of 30 mm Hg (dashed black line). The PFV is the slope of the line connecting the distal temporal margin of the transition zone with the superior proximal margin of the EGJ on the 30-mm Hg isobaric contour line (pink dashed line), expressed in centimeters/seconds. In this example, the PFV is 3.5 cm/s.

Figure 2

Achalasia subtypes. The subtypes are distinguished by 3 distinct manometric patterns of esophageal body contractility. Type I is illustrated in both a color pressure topography plot (A) and as a 3-dimensional plot to illustrate the pressure gradients spanning the esophagus and proximal stomach (B). In panel a, there is no significant pressurization within the body of the esophagus, and this would be classified as failed peristalsis with an IRP of 42 mm Hg. The 3-dimensional rendering of these pressure data in B clearly illustrates that esophagogastric flow cannot occur because the esophageal pressure is too low to overcome the EGJ high-pressure zone. C represents a swallow from a type II achalasia patient with compartmentalized pressurization spanning the entire length of the esophagus. The 3-dimensional rendering of these pressure data (D) illustrates that the isobaric column within the esophagus equals the EGJ pressure and would likely be associated with esophagogastric flow. E illustrates a pressure topography plot of a spastic contraction in a type III achalasia patient. Although this swallow is also associated with rapidly propagated pressurization, the pressurization is attributable to an abnormal lumen obliterating contraction. The 3-dimensional rendering of these pressure data (F) illustrates the peaks and valleys of that spastic contraction, and this swallow would likely appear as a rosary-bead pattern on fluoroscopy.

Figure 3

Flow chart of the patient population analyzed.

Figure 4

Maximal esophageal pressurization in the distal esophagus during the 10 test swallows among achalasia subtypes. Values plotted are the means for each patient at whatever locus along the distal segment exhibited the greatest pressure. Type II patients exhibited significantly greater pressures than type I, whereas type III patient pressures were greater than types I or II.