High-resolution manometry studies are frequently imperfect but usually still interpretable

Abstract

Background & aims: Clinical esophageal manometry can be technically challenging. We investigated the prevalence and causes of technically imperfect, high-resolution esophageal pressure topography (EPT) studies at a tertiary referral hospital.

Methods: We reviewed 2000 consecutive clinical EPT studies that had been performed with consistent technique and protocol. A study was considered technically imperfect if there was a problem with pressure signal acquisition, if the catheter did not pass through the esophagogastric junction (EGJ), or if there were fewer than 7 evaluable swallows (without double-swallowing, and so forth). Data from the technically imperfect studies were interpreted blindly to determine a diagnosis; this diagnosis was compared with the diagnosis based on chart review.

Results: We identified 414 technically imperfect studies (21% of the series). These were attributed to fewer than 7 evaluable swallows (58%), inability to traverse the EGJ (29%), sensor or thermal compensation malfunction (7%), and miscellaneous artifacts (6%). The most frequent causes of failure to traverse the EGJ were a large hiatal hernia (50%) and achalasia (24%). The condition most frequently associated with an incomplete swallow protocol was achalasia (33%). Despite the limitations, the diagnosis of achalasia was achieved correctly by blinded interpretation in 77% of cases and nonblinded interpretation in 94% of cases.

Conclusions: Technically imperfect EPT studies are common in a tertiary care center; large hiatal hernia and achalasia were the most frequent causes. However, despite the technical limitations, the data still could be interpreted, especially in the context of associated endoscopic and radiographic data.

Figure 1

Examples of technically imperfect studies. In Panel A the catheter did not pass through the EGJ because of a large hiatal hernia. During inspiration (white arrows), the pressure decreased in all the recording sensors indicating that all pressure sensors were in the chest. In Panel B, it was not possible to obtain 7 evaluable swallows because of double swallows and belches. In Panel C, a vascular artifact was observed in the distal esophagus. Panel D illustrates a technically imperfect study with multiple malfunctioning pressure sensors.

Figure 2

Causes of technically imperfect EPT studies. Fewer than 7 analyzable swallows and an inability to traverse the EGJ or diaphragm were the most common causes of technically imperfect studies.

Figure 3

Examples of technically imperfect studies in patients with achalasia. In Panel A, the EPT study was considered imperfect as each swallow was followed by a belch. The mean integrated relaxation pressure (IRP) was 10 mmHg. Esophageal residual contractions were observed with a borderline value of distal latency (4.8 s). This EPT was classified as rapid propagation by the blinded reviewers. The chart review revealed that the patient had a previous Heller myotomy and the managing physician’s diagnosis was treated type III achalasia. In Panel B, the catheter did not pass through the EGJ. The EPT diagnosis of achalasia was based on the absence of peristalsis, pan-esophageal pressurization and consistent EGD findings. In Panel C, each swallow was consistently followed by a belch. The EPT diagnosis of achalasia was based on the absence of EGJ relaxation (IRP= 32 mmHg) and absent peristalsis. In Panel D, dysfunction of several pressure sensors occurred intermittently. The EPT diagnosis of achalasia was based on the absence of EGJ relaxation (IRP= 22 mmHg), the absence of peristalsis and the occurrence of pan-esophageal pressurization.

Figure 4

False positive diagnosis of achalasia in patients with large hiatal hernias. In the two EPT studies the tip of the catheter was not in the abdominal cavity. In Panel A, absence of lower esophageal sphincter (LES) relaxation during swallowing was associated with absent peristalsis and pan-esophageal pressurization. In Panel B, absence of LES relaxation was associated with a premature contraction characterized by a distal latency (DL) < 4.5 s. The abnormal IRP is a manifestation of the abnormal EGJ position related to the large hernia and not an intrinsic defect in inhibition.