INTRODUCTION — Esophageal manometry is indicated in the evaluation of dysphagia or noncardiac chest pain in patients without evidence of mechanical obstruction, ulceration, or inflammation. It is also an important tool in the evaluation of gastroesophageal reflux disease (GERD), both for correct placement of pH electrodes and as an essential part of preoperative evaluation prior to antireflux procedures.
High resolution manometry (HRM) with esophageal pressure topography (EPT) plotting combines improvements in pressure sensing technology with a greatly increased number of pressure sensors and an analysis paradigm that displays data as a topographic plot that morphs anatomy and physiology.
This topic will discuss the critical features that distinguish HRM with EPT from conventional manometry, metrics for EPT, a classification scheme of motility disorders developed for HRM (Chicago Classification [CC]) and will detail the diagnostic criteria within this classification scheme. The indications for motility testing, technical aspects of conventional manometry, and the clinical manifestations and management of specific motility disorders are discussed separately. (See "Overview of gastrointestinal motility testing" and "Distal esophageal spasm and hypercontractile esophagus" and "Achalasia: Pathogenesis, clinical manifestations, and diagnosis" and "Overview of the treatment of achalasia".)
HIGH-RESOLUTION MANOMETRY (HRM)
Overview — The fundamental difference between conventional manometry and high resolution manometry (HRM) is the number of pressure sensors used and the spacing between them (figure 1) [1]. (See "Overview of gastrointestinal motility testing", section on 'Esophagus'.)
In contrast to conventional manometry where three to eight sensors are spaced at 3 to 5 cm intervals, HRM sensors are typically spaced 1 cm apart along the length of the manometric assembly. Hence, catheters with up to 36 sensors allow for simultaneous pressure readings spanning both sphincters and the entire interposed esophagus.
Esophageal pressure topography (EPT) is a three-dimensional plotting format devised for depiction of HRM studies. EPT interpolates pressure values between sensors to create a pressure continuum. Pressure magnitude is converted into a color scale using cold colors to denote low pressures and hot colors to denote higher pressures (figure 1). In an EPT plot, time and location within the esophagus are continuous variables and pressure magnitude is indicated at each x-y coordinate by color. The result is a seamless isobaric contour (IBC) map spanning from above the upper esophageal sphincter (UES) to below the esophagogastric junction (EGJ). This also allows for the depiction of real-time luminal pressure gradients and spatial transition points of contraction amplitude or propagation velocity along the esophagus that correlate with anatomic and/or physiologic landmarks.
Both EPT analysis and conventional manometry aim to characterize peristalsis and EGJ function. However, the types of measurements obtained differ substantially. Several novel metrics and nomenclature have been devised specifically to quantify esophageal function in EPT. (See 'Analysis' below and 'Classification of motility disorders by esophageal pressure topography (EPT)' below.)
Correlating manometric with clinical data — Esophageal manometry study results are correlated with the following clinical findings to establish a diagnosis:
●Patient presentation (presence and characteristics of dysphagia, chest pain)
●Imaging studies (eg, barium esophagram)
●Endoscopic findings
●Functional luminal imaging probe (FLIP) findings
Technique — The technical aspects of performing HRM studies mirror those of conventional manometry in terms of preprocedure patient preparation and transnasal intubation [2]. (See "Overview of gastrointestinal motility testing", section on 'Esophagus'.)
In HRM, once the manometric catheter is positioned across the EGJ, no further repositioning is required. Simultaneous assessment of sphincters and esophageal body with a single series of swallows is possible with the catheter in a single, fixed position. This is in contrast to conventional manometry where pull-though maneuvers and repeated catheter repositioning are required to separately assess the sphincters and different esophageal regions.
The data acquisition period with HRM also tends to be shorter than with conventional manometry, possibly increasing study acceptability and tolerability among patients.
Similar to conventional manometry, HRM is not dependent on any specific hardware and can be accomplished with different pressure transduction technologies such as water-perfused systems, solid state strain gauge devices, or Tact-array technology. However, as performance characteristics of each pressure transduction technology are unique, HRM requires its own set of reference values developed for each specific system.
Indications — The indications to perform HRM are the same as those described for conventional manometry and include the evaluation of dysphagia, gastroesophageal reflux disease (GERD) resistant to standard therapy, noncardiac chest pain, or systemic diseases affecting smooth muscle or the autonomic nervous system [3]. Studies using HRM suggest enhanced performance and accuracy for assessing motility disorders, especially in the sphincters, compared with conventional manometry [4,5]. Therefore, HRM has become the preferred manometric technique for the assessment of motility. (See "Overview of gastrointestinal motility testing", section on 'Esophagus'.)
Protocol summary — The study protocol is summarized as follows [6]:
●Begin the study with the patient in the supine position. Once the manometry catheter is positioned, the patient undergoes a 10-swallow protocol, consisting of 10 liquid swallows, each using 5 mL of water or saline (when using HRM with impedance). Next, one multiple rapid swallow (MRS) sequence is performed (ie, five liquid swallows, 2 mL each, administered using a 10 mL syringe, two to three seconds apart).
●Change patient position to upright. The patient undergoes a minimum of five liquid swallows, each using 5 mL of water or saline. The patient then undergoes rapid drink challenge (ie, ingestion of water, 200 mL, as quickly as possible through a straw) [7].
Other tests (eg, provocative swallows with viscous and solid food challenges) can be added to the basic protocol if a motility disorder is suspected but is not identified with the standardized protocol. However, there are few validated metrics to determine the significance of swallow patterns associated with these challenges [8-11].
Analysis
Pressure topography landmarks — EPT plots have several stereotypic features reflective of unique features of esophageal anatomy, physiology, and pathophysiology that are crucial to the accurate interpretation of these studies.
Anatomic sphincters — The upper and lower esophageal sphincters are usually easily visualized with EPT. Sphincter margins are characterized by an abrupt change in pressure along the luminal axis where a distinct high-pressure zone or pressure band can be identified. These high-pressure zones, together with sphincter relaxation with swallowing, allow for easy localization of the esophageal sphincters.
The EGJ is subject to substantial morphologic variability in EPT plots largely due to potential laxity in the attachment between the lower esophageal sphincter (LES) and the crural diaphragm (figure 2) [12]:
●With a completely normal EGJ, the crural diaphragm is directly superimposed on the LES, making it possible to identify the crural diaphragm only on the basis of its inspiratory contraction (figure 2).
●With slight or inconsistent separation between the LES and crural diaphragm, there is no low pressure gap between the two, and the presence or absence of hiatus hernia is indeterminant (figure 2) [12].
●With a definite hiatal hernia, there is complete separation between the LES and crural diaphragm, permitting the independent assessment of either constituent. Note that the respiratory inversion point (RIP) can localize either above the crural diaphragm or the LES in such cases; the implications of this remain controversial.
Some individuals have been observed to transition between morphologic types during prolonged manometric recordings, emphasizing the laxity of the LES-crural diaphragm attachment that can occur [13].
Contractile segments — Esophageal peristalsis consists of a progressive sequence of segmental contractions demarcated by three pressure troughs (proximal, middle, and distal) (figure 1) [14]. The first contractile segment is continuous with the pharyngeal and UES contraction, while the fourth contractile segment is the LES. The second and third contractile segments, comprising most of the tubular esophagus, are not always distinct and sometimes merge as a seamless contraction.
Transition zone — A stereotypical morphologic feature of peristalsis is the major pressure trough between the first and second contractile segments, alternatively labeled the "transition zone" [15-17]. Physiologic studies have concluded that this is the region of transition from central nervous system (CNS) control of peristalsis to enteric nervous system (myenteric plexus) control. Transition zone defects may be related to dysphagia in a small percentage of patients (<4 percent) [17].
Contractile deceleration point (CDP) — Conduction velocity, a defining feature of an esophageal contraction, is measured on EPT by the slope of the 30 mmHg IBC (figure 3). Conduction velocity is not constant along the length of the esophagus and is more rapid proximally than distally. Physiologic studies have demonstrated that the transition from rapid to slow propagation correlates with the formation of the phrenic ampulla, a transient structure composed of the effaced, elongated, and elevated LES [18].
The contraction deceleration point (CDP) demarcates the proximal region in which the conduction (peristaltic) velocity is fast from the distal region where propagation is slow, reflecting the progression from peristalsis to ampullary emptying [19]. The CDP location is determined on EPT plots by defining the intersection point between two tangent lines of the 30 mmHg isobaric contour: one extending distally from the transition zone and the other extending proximally from the EGJ when it reestablishes its normal post-deglutitive position. An added criterion is that the CDP is localized within 3 cm of the proximal margin of the EGJ [19].
EPT metrics — Several metrics and nomenclature have been devised specifically to quantify esophageal function in esophageal pressure topography (EPT) (table 1).
Integrated relaxation pressure (IRP) — IRP is a measure for assessing the adequacy of EGJ relaxation with swallowing.
Abnormal deglutitive LES relaxation is the most fundamental abnormality of esophageal motility [20]. However, using intraluminal manometry, LES pressure cannot be distinguished from other contributions to intraluminal pressure at the level of the EGJ, most notably, the crural diaphragm. Additionally, outflow obstruction caused by stenosis or extrinsic compression can lead to elevated intrabolus pressure that is indistinguishable from impaired LES relaxation. Consequently, the metric developed to distinguish normal from impaired EGJ relaxation was termed the IRP.
IRP is defined as the average minimum EGJ pressure for four seconds of relaxation (contiguous or noncontiguous) within 10 seconds of swallowing (upper sphincter relaxation).
The IRP is a complex metric as it involves localizing the margins of the EGJ, demarcating the time window following deglutitive upper sphincter relaxation within which EGJ relaxation will occur, applying an e-sleeve measurement within that 10-second time box (figure 4), and then determining the four seconds during which the e-sleeve value was least. IRP is the mean pressure during those four seconds.
The published upper limit of normal for the IRP is 15 mmHg which represents the 95th percentile in a series of 75 asymptomatic controls [20]. However, normal values are specific for specific manometric apparatus (sensor types and arrays). Additionally, the threshold value for defining a swallow as pathologic may require some degree of latitude based on the fact the concurrent contractile pattern may affect the intrabolus pressure generated at the EGJ [21]. Depending on these mitigating factors, the upper limit of normal for the IRP can be as low as 10 mmHg or as high as 22 mmHg.
Distal latency (DL) — Distal latency (DL) is a measure of peristaltic timing and is dependent on the integrity of deglutitive inhibition rather than peristaltic velocity [22]. DL is defined as the interval between UES relaxation and the CDP (figure 3). (See 'Contractile deceleration point (CDP)' above.)
Based on the DL, contractions are defined as premature or of normal latency. In normal subjects, the median DL is 6.2 seconds with a minimal value of 4.6 seconds, thereby establishing 4.5 seconds as the lower limit of normal [23]. In instances of increased intrabolus pressure, wherein the swallowed bolus is trapped between the distal esophageal contraction and the EGJ, the DL should be determined at an IBC pressure exceeding EGJ pressure so as not to mistake compartmentalized esophageal pressurization for a lumen-obliterating contraction. (See 'Pressurization patterns' below.)
Distal contractile integral (DCI) — Distal contractile integral (DCI) is a summary measure of the vigor of the distal esophageal contraction. The DCI is essentially a composite of the mean distal contractile amplitude, length of the distal esophagus, and contractile duration.
The DCI is measured for the segment spanning from the proximal to distal pressure troughs [4]. A box is constructed to delineate the contractile activity relegated to the second and third contractile segments (figure 5). The DCI is then calculated by summing the pressure measurements at each enclosed coordinate. To exclude the effects of vascular artifacts and/or intrabolus pressure in the DCI computation, the first 20 mmHg is discounted. Therefore, the DCI value is greater than zero only when foci of intra-esophageal pressure exceed 20 mmHg.
Contraction vigor — Although an ineffective contraction (meaning a contraction that did not clear a swallowed bolus from the esophagus) was originally defined in conventional manometry on the basis of low-amplitude peristalsis, this criterion was not used to define weak peristalsis in the first versions of the Chicago Classification (CC). Rather, contractions were categorized as "weak" because of small or large breaks in the 20-mmHg isobaric contour. Consequently, when correlating conventional line-tracing analysis with pressure topography analysis, one study found breaks in the 20-mmHg isobaric contour to be nonspecific for ineffective peristalsis [24]. To clarify the distinction between contractile vigor and the contraction pattern, CC version 4.0 (CC-4) separates these concepts and bases the evaluation of contractile vigor entirely on the DCI, using cutoff values of 100 mmHg·s·cm for failed peristalsis and 450 mmHg·s·cm for weak peristalsis. The value for weak peristalsis was derived directly from the study while the threshold for failed peristalsis represented a convenient compromise between proposed values ranging from 50 to 150 mmHg·s·cm. Both failed and weak peristaltic contractions are ineffective. At the other extreme of contractile vigor, it was accepted to keep the cutoff for hypercontractility at 8000 mmHg·s·cm but to eliminate the "hypertensive" designation for contractions with DCI between 5000 and 8000 mmHg·s·cm because it has no apparent clinical significance.
Contraction vigor based on DCI values are defined as follows:
●Failed peristalsis – DCI <100 mmHg·s·cm
●Weak peristalsis – DCI >100 mmHg·s·cm, but <450 mmHg·s·cm
●Ineffective – Failed peristalsis or weak peristalsis or peristaltic break >5 cm in the setting of a DCI ≥450 mmHg·s·cm
●Normal – DCI 450 to 8000 mmHg·s·cm
●Hypercontractile – DCI >8000 mmHg·s·cm
With respect to hypercontractility, there are instances in which this phenomenon involves the LES as well as the second and third contractile segments, and others in which it seemingly only involves the LES (figure 6). Excluding the LES from the measurement domain in such cases might then fail to detect the abnormality; hence, in the CC-4 it was decided to incorporate the LES into the DCI measurement domain in these instances and to use the existing cutoff value (8000 mmHg) to define hypercontractility. It was reasoned that the degree to which the LES pressure normally exceeds 20 mmHg is sufficiently slight such that its "normal" contribution to the DCI would be trivial.
Contraction pattern — Irregularities in the contraction pattern characterized by breaks in the 20 mmHg isobaric contour but not ineffective define "fragmented peristalsis." However, since small breaks (<3 cm) in the 20 mmHg isobaric contour are frequently encountered in normal subjects [25], putting them within the realm of normal, it requires large breaks (>5 cm) in the 20-mmHg isobaric contour to meet this definition. Larger breaks are more common in patients with dysphagia than in controls (14 versus 4 percent) [26]. Hence, ineffective contractions include fragmented contractions that are defined as contractions with a large break in the 20-mmHg isobaric contour, but normal or elevated DCI (>450 mmHg·s·cm) [27]. Similarly, a premature contraction must have both a DL <4.5 seconds and a DCI >450 mmHg·s·cm to qualify; otherwise it would be considered failed and fall under the category of "ineffective contractions."
Pressurization patterns — The distinction between an esophageal contraction and pressurization is that while a contraction signifies a lumen-obliterating squeeze of the circular muscle clamping down on the pressure recording device, pressurization is recorded within an open lumen; for example, between the closed upper and lower sphincters [28,29]. In EPT, pressurization is evident by straight, vertical bands of increased pressure "blocked" at either end by a greater, obstructing pressure.
When pressurization involves the entire esophagus, it is termed as "panesophageal pressurization" (figure 7) [30]. This pattern defines type II achalasia (see 'Disorders of EGJ outflow obstruction' below). A more limited region of pressurization, termed "compartmentalized pressurization," can occur between an esophageal contraction and the EGJ in the setting of hiatus hernia, a crural diaphragm contraction, after fundoplication surgery, or after bariatric surgery [31]. Proximal compartmentalized pressurization can also occur in the setting of isolated, nonperistaltic distal esophageal contractions.
CLASSIFICATION OF MOTILITY DISORDERS BY ESOPHAGEAL PRESSURE TOPOGRAPHY (EPT) — The Chicago Classification (CC, now in version 4.0 [CC-4]) of esophageal motility is an algorithmic scheme for diagnosis of esophageal motility disorders from clinical esophageal pressure topography (EPT) studies [6]. The CC-4 esophageal motility disorders, along with their criteria, are outlined in the table (table 2). A key feature of the CC is the categorization of esophageal motility disorders into conditions never seen in normal individuals and those that are defined on the basis of being statistically outside of the norm (expected in approximately 5 percent of a "normal" population) but not necessarily indicative of pathology.
Efforts have been made to link the CC diagnoses to conventional manometric diagnoses when possible. However, with the use of HRM and EPT metrics, the CC has essentially redefined manometric diagnoses such that conventional methods are mostly of historical interest. (See 'EPT criteria for motility disorders' below.)
Stepwise approach to EPT analysis — Diagnostic flowcharts can progressively identify physiologic dysfunction into the following: disorders of esophagogastric junction (EGJ) outflow obstruction and disorders of esophageal peristalsis (algorithm 1A-B).
Step 1: Assess the EGJ
●EGJ morphology – Although EGJ morphology (figure 2) is not a defining criterion for any of the motility disorders (table 2), determining the existence of a hiatus hernia is an important clinical finding. (See "Hiatus hernia".)
A hiatus hernia may cause the manometric catheter to not traverse the EGJ into the intra-abdominal space thereby distorting EPT metrics, and potentially compromising the study. Intra-abdominal location of the manometric catheter is verified by noting that inspiration augments the recorded pressure (as opposed to decreasing the recorded pressure when the catheter is located in the mediastinum). The point of transition between the two is the respiratory inversion point (RIP), which is usually at the level of the crural diaphragm (CD) (except with larger hiatal hernias). (See 'Anatomic sphincters' above.)
●EGJ pressure – Similar to EGJ morphology, the measurement of basal EGJ pressure is not a defining criterion for any of the motility disorders, but a hypertensive or hypotensive EGJ pressure can be an important clinical finding pertinent to the diagnosis of achalasia or gastroesophageal reflux disease (GERD), respectively. (See 'Disorders of EGJ outflow obstruction' below.)
●Integrated relaxation pressure (IRP) – The determination of normal or abnormal EGJ relaxation after swallowing is made based on the median value of the IRP among the 10 test swallows (see 'Integrated relaxation pressure (IRP)' above). IRP is a major diagnostic criterion for all subtypes of achalasia and for EGJ outflow obstruction. (See 'Disorders of EGJ outflow obstruction' below.)
Step 2: Characterize esophageal contractility
●Peristaltic vigor and pattern (figure 8).
●Each test swallow should be categorized as intact, weak, failed, hypercontractile, or fragmented. Only swallows of DCI >450 mmHg·s·cm can be categorized as premature or fragmented. (See 'Distal latency (DL)' above and 'Contraction pattern' above and 'Distal contractile integral (DCI)' above.)
●DL: Measurement of the DL requires that the CDP be reliably identifiable since it is the interval between upper esophageal sphincter (UES) relaxation and the CDP (figure 3) (see 'Distal latency (DL)' above and 'Contractile deceleration point (CDP)' above). In practical terms, this means that the DCI needs to be >450 mmHg·s·cm.
Premature contractions are of particular significance because these are infrequently encountered in normal individuals and are important diagnostic criteria for type III achalasia and distal esophageal spasm (DES) [32]. (See 'Disorders of EGJ outflow obstruction' below and 'Contractile deceleration point (CDP)' above.)
●DCI (figure 5): Although initially devised as a measurement to define hypercontractility (eg, nutcracker or jackhammer esophagus), the DCI can be measured on any swallow and is also used as the means of identifying failed peristalsis (DCI <100 mmHg·s·cm) or weak peristalsis (DCI <450 mmHg·s·cm) [33]. (See 'Distal contractile integral (DCI)' above and 'Hypercontractile esophagus' below.)
Step 3: Characterize pressurization patterns, if present
●Panesophageal pressurization, defined by the 30 mmHg isobaric contour, is a defining characteristic of type II achalasia. Compartmentalized pressurization is a frequent finding in EGJ outflow obstruction. (See 'Disorders of EGJ outflow obstruction' below.)
These pressurization patterns (figure 7) are defined independently of the IRP, but are much more prevalent when the IRP is abnormal. (See 'Pressurization patterns' above and 'Integrated relaxation pressure (IRP)' above.)
EPT criteria for motility disorders — Esophageal motility disorders can be classified into disorders of esophagogastric junction (EGJ) outflow obstruction and disorders of peristalsis (table 2).
Disorders of EGJ outflow obstruction — Disorders of EGJ outflow include achalasia and EGJ outflow obstruction:
●Achalasia - Esophageal pressure topography (EPT) criteria for achalasia subtypes (figure 9):
•Type I – Median IRP >upper limit of normal, 100 percent failed peristalsis, minimal pressurization within the esophagus.
•Type II – Median IRP >upper limit of normal, no normal peristalsis, panesophageal pressurization with ≥20 percent of swallows.
•Type III – Median IRP >upper limit of normal, no normal peristalsis, preserved fragments of nonpropagating distal peristalsis or premature (spastic) contractions with DCI >450 mmHg·s·cm with ≥20 percent of swallows.
●Clinical implications – With conventional manometry, achalasia was loosely subdivided into classic and vigorous subtypes; however, there was no consensus on diagnostic criteria or on whether or not such a distinction was meaningful. (See "Achalasia: Pathogenesis, clinical manifestations, and diagnosis", section on 'Diagnostic evaluation'.)
With HRM, three discernible achalasia subtypes were defined based on distinct patterns of esophageal pressurization associated with lower esophageal sphincter (LES) dysfunction (figure 9) [30]. The key significance of this observation is that each subgroup has distinct physiology and unique treatment considerations. Treatment for achalasia is discussed in detail separately. (See "Overview of the treatment of achalasia".)
●EGJ outflow obstruction – EGJ outflow obstruction can be suspected based on manometric findings but requires confirmation with other clinical data (symptoms [eg, dysphagia], imaging, endoscopy, functional luminal imaging probe) because it can be related to artifact [34] (see 'Correlating manometric with clinical data' above):
•EPT criteria – Median IRP >upper limit of normal, some instances of intact peristalsis or weak peristalsis such that the criteria for achalasia are not met (figure 7).
•Clinical implications – EGJ outflow obstruction does not meet diagnostic criteria of achalasia because some peristalsis is preserved. However, impaired LES deglutitive relaxation is observed in both conditions, and the treatment can be similar (provided that EGJ outflow obstruction is confirmed with complimentary studies). Therapy is typically directed towards lowering LES pressure with botulinum toxin, dilation, surgical myotomy, or per oral endoscopic myotomy. Outcome data regarding this entity are limited.
While EGJ outflow obstruction can be an incomplete expression or evolving case of achalasia [35], it has also been reported to occur in benign and malignant infiltrative disorders. Therefore, endoscopic ultrasound and/or CT imaging to rule out neoplasia should be considered as part of the evaluation [31,36].
Disorders of peristalsis
Absent contractility
●EPT criteria – Normal median IRP, 100 percent of swallows with failed peristalsis (figure 8) (see 'Integrated relaxation pressure (IRP)' above). Note that achalasia should be considered when IRP values are borderline and when there is evidence of esophageal pressurization.
●Clinical implications – Absent contractility is associated with poor esophageal bolus transit and can be associated with dysphagia for both liquids and solids. The two main associated conditions are GERD and collagen vascular diseases (eg, scleroderma). (See "Gastrointestinal manifestations of systemic sclerosis (scleroderma)", section on 'Esophageal involvement'.)
Patients with absent contractility and an impaired antireflux barrier are prone to very severe esophagitis from gastroesophageal reflux. Absent contractility is also encountered in patients with post-fundoplication dysphagia.
Distal esophageal spasm (DES)
●EPT criteria – Normal median IRP, >20 percent premature contractions (DL <4.5 seconds) (figure 10). (See 'Integrated relaxation pressure (IRP)' above.)
●Clinical implications – Early iterations of the CC adopted "simultaneous contractions," as described in conventional manometry (contractile front velocity [CFV] >9 cm/second) as defining criterion for DES. However, subsequent evaluation demonstrated this to be a nonspecific finding because of regional variability in contractile velocity, the observation that regions of apparent rapid contraction velocity often occurred with weak peristalsis, and the lack of correlation between these "spastic" events and symptoms [32].
Consequently, the metric of DL was proposed as an alternative, more specific measure to define DES [37] (see 'Distal latency (DL)' above). Reduced DL is a rare finding, encountered in only 24 of 1070 consecutive patients who underwent manometry in one series [32]. However, all 24 of these patients had a dominant symptom of dysphagia or chest pain and were diagnosed and managed as either DES (6 patients) or spastic (type III) achalasia (18 patients). That study suggested that the diagnosis of DES based on an abnormal DL defined a distinct clinical phenotype. However, further studies evaluating the clinical outcomes of patients diagnosed with DES based on reduced DL are needed. (See "Distal esophageal spasm and hypercontractile esophagus".)
Hypercontractile esophagus
●EPT criteria – At least two swallows with a DCI >8000 mmHg·s·cm with single-peaked or multi-peaked contraction (figure 11). There are three subgroups of hypercontractile esophagus (see 'Distal contractile integral (DCI)' above):
•Single-peaked hypercontractile swallows
•Jackhammer with repetitive prolonged contractions
•Hypercontractile swallows with a vigorous LES after contraction
●Clinical implications – Hypercontractile esophagus is a relatively rare disorder, accounting for just 4 percent of patients referred for manometric evaluation in a large series from tertiary referral centers [33]. Patients usually have associated dysphagia. In conventional manometry, the nearest equivalent to hypercontractile esophagus is nutcracker esophagus. (See "Distal esophageal spasm and hypercontractile esophagus".)
Hypercontractile esophagus may be a primary disorder of excessive excitation of the smooth muscle esophagus or potentially a reaction to EGJ outflow obstruction [33]. When this pattern is associated with a distal esophageal obstruction, the motility abnormality will resolve with resolution of the obstruction.
Ineffective esophageal motility (IEM)
●Esophageal pressure topography (EPT) criteria – Median IRP <15 mmHg and ≥50 percent failed peristalsis or >70 percent ineffective swallows (figure 8). Ineffective swallows include (see 'Contraction pattern' above):
•Failed peristalsis – DCI <100 mmHg·s·cm
•Weak peristalsis – DCI >100 mmHg·s·cm, but <450 mmHg·s·cm
•Fragmented swallow – Large breaks (>5 cm) in the 20-mmHg isobaric contour in the setting of a DCI ≥450 mmHg s cm
●Clinical implications: IEM is associated with impaired bolus transit through the esophagus and nonobstructive dysphagia [19]. This term has been adopted from conventional manometry substituting DCI criteria for failed and weak contractions [24]. (See 'Distal contractile integral (DCI)' above.)
Data supporting pharmacologic interventions for IEM are limited. (See "Medical management of gastroesophageal reflux disease in adults", section on 'PPI refractory symptoms'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Achalasia" and "Society guideline links: Esophageal manometry and pH testing".)
SUMMARY AND RECOMMENDATIONS
●High-resolution manometry (HRM) for the evaluation of esophageal motility disorders employs catheters with up to 36 longitudinally-distributed sensors allowing for simultaneous pressure readings within both sphincters and the esophageal body. (See 'High-resolution manometry (HRM)' above.)
●Esophageal pressure topography (EPT) is a three-dimensional plotting format devised for depiction of HRM studies wherein both time and location within the esophagus are continuous variables and pressure magnitude is indicated at each x-y coordinate by color. The result is a seamless isobaric contour (IBC) map spanning from above the upper esophageal sphincter (UES) to below the esophagogastric junction (EGJ) (figure 1). (See 'High-resolution manometry (HRM)' above.)
●The interpretation of clinical EPT studies required the development of metrics customized to highlight the key pathophysiologic features of esophageal motor disorders.
The most important of these are the integrated relaxation pressure (IRP) for assessing the adequacy of EGJ relaxation with swallowing, the distal contractile integral (DCI) for characterizing the vigor of the distal esophageal contraction, and the distal latency (DL) to identify instances of premature distal esophageal contraction. (See 'EPT metrics' above.)
●The Chicago Classification version 4.0 (CC-4) of esophageal motility is an algorithmic scheme for diagnosis of esophageal motility disorders from clinical EPT studies. A key feature of CC-4 is the categorization of esophageal motility disorders into disorders with EGJ outflow obstruction and disorders of esophageal peristalsis. (See 'Classification of motility disorders by esophageal pressure topography (EPT)' above and 'Stepwise approach to EPT analysis' above.)
●The CC has clarified the diagnosis of achalasia, both by standardizing the diagnostic criteria and by defining three distinct subtypes based on the pattern of associated esophageal contractility: essentially no contractility in type I, panesophageal pressurization in type II, and premature contractions in type III. (See 'Disorders of EGJ outflow obstruction' above.)
●HRM with EPT has also defined the entity of EGJ outflow obstruction in which there is preserved peristalsis in association with EGJ outflow obstruction of severity consistent with achalasia. In fact, EGJ outflow obstruction can be a variant form of achalasia, but it also occurs in the setting of EGJ stenosis (eg, inflammatory, neoplastic) or related to a manometric artifact. An endoscopic ultrasound and/or CT to rule out a neoplasia should be considered in patients with EGJ outflow obstruction on HRM. (See 'Disorders of EGJ outflow obstruction' above.)
●The CC has clarified the diagnosis of distal esophageal spasm (DES), defining it on the basis of premature contraction (reduced latency relative to the timing of the swallow) in the distal esophagus as opposed to the very nonspecific finding of increased propagation velocity. (See 'Distal esophageal spasm (DES)' above.)
