Characterization of esophageal striated muscle in patients with achalasia

Esophageal body motility in achalasia and Chagas' disease

Previous studies have correlated esophageal body motility findings in idiopathic (IdAc) achalasia and achalasia secondary to Chagas' disease (ChAc) with degree of megaesophagus. The aim of this study was to compare esophageal body manometric data in patients with IdAc and achalasia secondary to Chagas' disease and correlate it with the degree of megaesophagus and symptom duration. One hundred nontreated patients with achalasia, 79% IdAc and 21% secondary to ChAc were compared with regards to age of presentation, duration of symptoms, amplitude and duration of simultaneous contractions, frequency of failed contractions, and degree of megaesophagus. Seventy-one percent of patients were classified as nonadvanced megaesophagus (60 [76%] with IdAc and 11 [52%] with ChAc) and 29% as advanced megaesophagus (19 [24%] with IdAc and 10 [48%] with ChAc, P= 0.04). In IdAc but not in ChAc, the symptom duration was significantly longer in advanced megaesophagus (A) compared with nonadvanced megaesophagus (NA) (34.8 ± 6.3 months vs. 95.4 ± 22.2 months, P= 0.001). There was no difference in amplitude and duration of simultaneous contractions in both achalasia groups (P > 0.05). Duration of contractions were longer in IdAc compared with ChAc in (NA) (P < 0.05), but not in (A). In IdAc but not in ChAc the amplitude of simultaneous contractions decreased with increased esophageal dilatation (P < 0.05). In ChAc but not in IdAC, the duration of contractions increased with esophageal dilatation (P < 0.05). Failed contractions were more frequent in ChAc group (28.6%) than in IdAc (10% -P= 0.03). Patients with ChAc have a higher prevalence of advanced megaesophagus compared with IdAc at diagnosis. In IdAc there was a strong correlation between advanced megaesophagus and longer symptom duration, suggesting disease progression over time, not observed in ChAc in which a more extensive denervation occurs earlier in the disease process.

Effect of bolus volume on proximal esophageal contractions of patients with Chagas' disease and patients with idiopathic achalasia

Chagas' disease and idiopathic achalasia patients have similar impairment of distal esophageal motility. In Chagas' disease, the contractions occurring in the distal esophageal body are similar after wet or dry swallows. Our aim in this investigation was to evaluate the effect of wet swallows and dry swallows on proximal esophageal contractions of patients with Chagas' disease and with idiopathic achalasia. We studied 49 patients with Chagas' disease, 25 patients with idiopathic achalasia, and 33 normal volunteers. We recorded by the manometric method with continuous water perfusion the pharyngeal contractions 1 cm above the upper esophageal sphincter and the proximal esophageal contractions 5 cm from the pharyngeal recording point. Each subject performed in duplicate swallows of 3-mL and 6-mL boluses of water and dry swallows. We measured the time between the onset of pharyngeal contractions and the onset of proximal esophageal contractions (pharyngeal-esophageal time [PET]), and the amplitude, duration, and area under the curve (AUC) of proximal esophageal contractions. Patients with Chagas' disease and with achalasia had longer PET, lower esophageal proximal contraction amplitude, and lower AUC than controls (P≤ 0.02). In Chagas' disease, wet swallows caused shorter PET, higher amplitude, and higher AUC than dry swallows (P≤ 0.03).There was no difference between swallows of 3- or 6-mL boluses. There was no difference between patients with Chagas' disease and with idiopathic achalasia. We conclude that patients with Chagas' disease and with idiopathic achalasia have a delay in the proximal esophageal response and lower amplitude of the proximal esophageal contractions.

A high-resolution view of achalasia

BACKGROUND

High-resolution manometry (HRM) makes it possible to better evaluate spatial and temporal characteristics of esophageal motor function. This technology is revealing new observations regarding disordered motor function in esophageal diseases.

GOAL

The aim of this study was to define the essential features of achalasia using HRM.

STUDY

We performed HRM on 27 patients with achalasia, 10 patients with gastroesophageal reflux disease, and 10 controls. Ten 5 mL water swallows were recorded with a solid-state manometric assembly incorporating 36 circumferential sensors spaced at 1-cm intervals.

RESULTS

The resting lower esophageal sphincter pressure was greater in achalasia than in controls or gastroesophageal reflux disease. There was an absence of peristalsis in the smooth muscle esophagus and failure of lower esophageal sphincter relaxation. The resting upper esophageal sphincter pressure was not different among the 3 groups. In addition to the typical manometric findings of achalasia, new observations are included. Esophageal shortening, pressurization of the esophagus, and rhythmic contractions of the upper esophageal sphincter and striated muscle esophagus were frequently observed.

CONCLUSIONS

HRM demonstrates alterations of esophageal motor function in achalasia that are not easily observed with other manometric techniques.

The neural regulation of the mammalian esophageal motility and its implication for esophageal diseases

In contrast to the tunica muscularis of the stomach, small intestine and large intestine, the external muscle layer of the mammalian esophagus contains not only smooth muscle but also striated muscle fibers. Although the swallowing pattern generator initiates the peristaltic movement via vagal preganglionic neurons that project to the myenteric ganglia in the smooth muscle esophagus, the progressing front of contraction is organized by a local reflex circuit composed by intrinsic neurons similarly to other gastrointestinal tracts. On the other hand, the peristalsis of the striated muscle esophagus is both initiated and organized by the swallowing pattern generator via vagal motor neurons that directly innervate the muscle fibers. The presence of a distinct ganglionated myenteric plexus in the striated muscle portion of the esophagus had been enigmatic and neglected in terms of peristaltic control for a long time. Recently, the regulatory roles of intrinsic neurons in the esophageal striated muscle have been clarified. It was reported that esophageal striated muscle receives dual innervation from both vagal motor fibers originating in the brainstem and varicose intrinsic nerve fibers originating in the myenteric plexus, which is called 'enteric co-innervation' of esophageal motor endplates. Moreover, a putative local neural reflex pathway that can control the motility of the striated muscle was identified in the rodent esophagus. This reflex circuit consists of primary afferent neurons and myenteric neurons, which can modulate the release of neurotransmitters from vagal motor neurons in the striated muscle esophagus. The pathogenesis of some esophageal disorders such as achalasia and gastroesophageal reflux disease might be involved in dysfunction of the neural networks including alterations of the myenteric neurons. These evidences indicate the physiological and pathological significance of intrinsic nervous system in the regulation of the esophageal motility. In addition, it is assumed that the components of intrinsic neurons might be therapeutic targets for several esophageal diseases.

Enteric co-innervation of striated muscle fibres in human oesophagus

Oesophageal striated muscle of several mammalian species receives dual innervation from both vagal motor fibres originating in the brain stem and enteric nerve fibres originating in myenteric ganglia. The aim of this study was to investigate this so-called enteric co-innervation in the human oesophagus. Histochemical and immunohistochemical methods combined with confocal laser scanning microscopy were utilized to study innervation of 14 oesophagi obtained from body donors (age range 47-95 years). In addition, the distribution of striated and smooth muscle in longitudinal and circular layers of the tunica muscularis was studied semiquantitatively. The upper half of the oesophagus was built up of both muscle types with a predominance (>50-60%) of striated muscle, whereas the lower half consisted of smooth muscle only. The majority of motor endplates was compact and ovoid. Enteric nerve fibres on approximately 17% of motor endplates stained for neuronal nitric oxide synthase, vasoactive intestinal polypeptide, galanin and neuropeptide Y and were completely separated from vagal cholinergic nerve terminals. There was remarkable variability of co-innervation rates between striated muscle bundles with some reaching almost 50%. Myenteric neurons representing the putative source of enteric co-innervating nerve fibres, stained for all these markers, which were almost completely colocalized with NADPH-diaphorase. Our study provides evidence for enteric co-innervation of striated muscle in human oesophagus. From these and recent functional results in various rodent species, we suggest that this innervation component represents an integral part of an intramural reflex mechanism for local most likely inhibitory modulation of oesophageal motility.

Regional esophageal dysfunction in scleroderma and achalasia using multichannel intraluminal impedance and manometry

BACKGROUND

Achalasia and scleroderma are esophageal motility abnormalities characterized by severely impaired bolus transit. Combined multichannel intraluminal impedance and manometry (MII-EM) enables the simultaneous measurement of intraesophageal pressures and bolus transit at various levels within the esophagus.

AIM

The aim of the study was to evaluate and characterize regional pressure and transit profile differences in scleroderma and achalasia patients.

METHODS

A retrospective analysis was carried out of MII-EM studies of patients with scleroderma (15), achalasia (20), and poorly relaxing lower esophageal sphincter (LES) with normal esophageal body function (20) as a control group. Bolus presence and segmental transit were evaluated by MII.

RESULTS

In patients with achalasia, bolus transit was impaired across all four sites compared with scleroderma (P < 0.0125) even though distal esophageal pressures were higher (P < 0.05) in patients with achalasia. Pressures in patients with achalasia were similar across all four sites (ANOVA; saline, P = 0.373; viscous, P = 0.615). Bolus clearance rates and contraction amplitudes in patients with scleroderma decreased from proximal to distal. In the control group, bolus clearance was complete during > or = 83% of all swallows and esophageal pressure amplitudes increased distally.

CONCLUSION

While the overall bolus transit is impaired in both patients with achalasia and scleroderma regional pressure and bolus transit differences exist. Bolus transit abnormalities result from abnormal esophageal body contraction and not abnormal LES relaxation.

The Effect of an Effortful Swallow on the Normal Adult Esophagus

The effect of an effortful swallow on the healthy adult esophagus was investigated using concurrent oral and esophageal manometry (water perfusion system) on ten normal adults (5 males and 5 females, 20-35 years old) while swallowing 5-ml boluses of water. The effects of gender, swallow condition (effortful versus noneffortful swallows), and sensor site within the oral cavity, esophageal body, and lower esophageal sphincter (LES) were examined relative to amplitude, duration, and velocity of esophageal body contractions, LES residual pressure, and LES relaxation duration. The results of this study provide novel evidence that an effortful oropharyngeal swallow has an effect on the esophageal phase of swallowing. Specifically, effortful swallowing resulted in significantly increased peristaltic amplitudes within the distal smooth muscle region of the esophagus, without affecting the more proximal regions containing striated muscle fibers. The findings pertaining to the LES are inconclusive and require further exploration using methods that permit more reliable measurements of LES function. The results of this study hold tremendous clinical potential for esophageal disorders that result in abnormally low peristaltic pressures in the distal esophageal body, such as achalasia, scleroderma, and ineffective esophageal motility. However, additional studies are necessary to both replicate and extend the present findings, preferably using a solid-state manometric system in conjunction with bolus flow testing on both normal and disordered populations, to fully characterize the effects of an effortful swallow on the esophagus.

Differences in response of the proximal esophagus to wet swallows in patients of Chagas' disease and idiopathic achalasia

Chagas' disease and idiopathic achalasia have similar esophageal manifestations such as absent or incomplete lower esophageal sphincter relaxation and aperistalsis in the esophageal body (alterations seen mainly in the distal esophageal body). Our aim in this paper was to study the response of the proximal esophageal body to wet swallows in patients with Chagas' disease and patients with idiopathic achalasia. We retrospectively analyzed the time interval between the onset of the pharyngeal contractions 1 cm proximal to the upper esophageal sphincter, as well as 5 cm distal to the pharyngeal measurement. Amplitude, duration and area under the curve of contractions in the proximal esophagus were also determined in 42 patients with Chagas' disease (15 with associated esophageal dilatation), 21 patients with idiopathic achalasia (14 with concomitant esophageal dilatation) and 31 control subjects. The time between the onset of pharyngeal and proximal esophageal contractions was longer in patients with Chagas' disease and in those with esophageal dilatation (1.39 +/- 0.16 s) than in control subjects (0.86 +/- 0.04 s, P < 0.01). The amplitude of proximal esophageal contractions was lower in patients with idiopathic achalasia and esophageal dilatation (60.9 +/- 16.3 mmHg) than in control subjects (89.7 +/- 6.9 mmHg, P = 0.06). The authors conclude that in patients with advanced esophageal disease, the proximal esophageal contractions in Chagas' disease have a delayed response to wet swallows when compared with controls, and that the amplitude of proximal esophageal contractions was lower than expected in patients with idiopathic achalasia.

Esophageal contractions in Chagas' disease and in idiopathic achalasia

GOALS

The aim of this study was to compare the esophageal contractions in Chagas' disease and in idiopathic achalasia.

BACKGROUND

It is suggested that the esophageal involvement caused by Chagas' disease and by idiopathic achalasia, although similar, shows some differences.

STUDY

We studied the contractions at 2, 7, 12, and 17 cm below the upper esophageal sphincter in 25 patients with idiopathic achalasia (15 with dilatation), 52 with Chagas' disease (22 with dilatation), and 18 controls. Each subject performed 5 swallows of a 5-mL bolus of water alternated with 5 dry swallows.

RESULTS

In the distal esophageal body, the amplitude was lower in patients than in controls. Among patients with esophageal dilatation, the proximal amplitude was lower in patients with idiopathic achalasia, and the time interval between the contractions at 2 and 7 cm was longer in patients with Chagas' disease, the number of failed contractions was higher in Chagas' disease, and simultaneous contractions were more frequent in idiopathic achalasia. The simultaneous isobaric pressure in the distal esophagus was associated with an increase in proximal pressure that was higher than distal but lower than proximal swallowing pressure.

CONCLUSION

The results suggested that idiopathic achalasia and Chagas' disease cause similar impairment of distal esophageal motility, but in patients with esophageal dilatation the impairment of proximal motility may be not the same.

Proximal and distal esophageal contractions in patients with vigorous or classic esophageal Chagas' disease

BACKGROUND

Some patients with achalasia have distal esophageal contraction amplitude in the normal range, a condition called vigorous achalasia, and others have low contraction amplitude, a condition named classic achalasia. The difference in distal contraction amplitude may also be associated with a difference in proximal contraction amplitude.

AIM

To study the proximal and distal esophageal contractions in patients with Chagas' disease.

MATERIAL AND METHODS

We studied 28 patients with Chagas' disease, all with dysphagia and an esophageal radiologic examination with retention without dilation, and 18 controls. The patients with Chagas' disease had vigorous achalasia (distal amplitude over 34 mm Hg, n = 13) or classic achalasia (distal amplitude below 34 mm Hg, n = 15). We measured the contractions by the manometric method with continuous perfusion at 2, 7, 12 and 17 cm below the upper esophageal sphincter after five swallows of a 5 mL bolus of water.

RESULTS

There was no difference in proximal amplitude of contractions between classic or vigorous achalasia, and controls. In the proximal esophagus there was also no difference in duration or area under curve of contractions. In the distal esophagus, duration and area under curve were lower in classic than vigorous disease. Failed and simultaneous contractions were more frequent in patients than controls. Simultaneous contractions were seen more frequently in classic disease, and peristaltic contractions were seen more frequently in vigorous disease.

CONCLUSION

We did not find differences in proximal esophageal contractions of patients with classical or vigorous esophageal Chagas' disease, except for the higher number of simultaneous contractions seen in classic disease.

Impedance characteristics of esophageal motor function in achalasia

Detailed data on patterns of esophageal bolus transport in patients with achalasia are still lacking. To study these we applied the novel technique of multichannel intraluminal impedance measurements. Ten patients with achalasia were studied using a 16 channel system. Liquid and semisolid boluses of 10 mL were applied with the patients in a supine position. Patterns of bolus transport were determined and analyzed as compared to results obtained from 20 healthy subjects. The healthy subjects featured a unique typical primary peristalsis pattern independent of bolus viscosity. In contrast, achalasia patients demonstrated different impedance characteristics, including: (i) significantly lower baseline esophageal impedance during the resting state as compared with healthy volunteers (999 omega +/- 108 versus 2749 omega +/- 113); (ii) failed bolus transport through the esophagus in all cases; (iii) impedance evidence of luminal content regurgitation in 35% of the swallows (iv) impedance evidence of pathological air movement within the proximal esophagus during deglutition in 38% of the swallows, so called air trapping. Thus, impedance characteristics of achalasia have been defined and can be attributed to known symptoms of achalasia. They can be used as basic findings for further classification of pathological bolus transports in other esophageal motility disorders.

[Comparison between idiopathic achalasia and achalasia caused by Chagas' disease: a review on the publications about the subject]

BACKGROUND

Although idiopathic achalasia and achalasia caused by Chagas' disease have the same clinical manifestations and treatment, both with destruction of the esophageal myenteric plexus, it is possible that there are differences in the alterations of esophageal motility between the two diseases, caused by different grades of impairment of the excitatory and inhibitory esophageal neurons.

AIMS

We performed a review of papers with results about the pathophysiology and esophageal motility alterations in idiopathic achalasia and Chagas' disease.

DATE SOURCES

We reviewed papers which included data about the characteristics of idiopathic achalasia and Chagas' disease.

DATA SYNTHESIS

Impairment of inhibitory esophageal neurons was shown in the two diseases. The results of the studies of the effects of atropine, edrophonium and botulin toxin suggested that the excitatory innervation is more intensely impaired in Chagas' disease than in idiopathic achalasia, explaining the increase in the lower esophageal sphincter pressure found in achalasia. The patients with Chagas' disease have more circulating muscarinic cholinergic receptor M2 autoantibodies than patient with idiopathic achalasia. The duration of the contractions in the esophageal body is longer in idiophatic achalasia than in Chagas' disease.

CONCLUSIONS

The papers that studied Chagas' disease and idiopathic achalasia, mainly those which studied both diseases with the same methods, suggested that there are different grades of esophageal involvement by the two diseases, mainly the most important involvement of excitatory innervation in Chagas' disease than in idiopathic achalasia.

Esophageal striated muscle contractions in patients with Chagas' disease and idiopathic achalasia

Chagas' disease causes degeneration and reduction of the number of intrinsic neurons of the esophageal myenteric plexus, with consequent absent or partial lower esophageal sphincter relaxation and loss of peristalsis in the esophageal body. The impairment of esophageal motility is seen mainly in the distal smooth muscle region. There is no study about esophageal striated muscle contractions in the disease. In 81 patients with heartburn (44 with esophagitis) taken as controls, 51 patients with Chagas' disease (21 with esophageal dilatation) and 18 patients with idiopathic achalasia (11 with esophageal dilatation) we studied the amplitude, duration and area under the curve of esophageal proximal contractions. Using the manometric method and a continuous perfusion system we measured the esophageal striated muscle contractions 2 to 3 cm below the upper esophageal sphincter after swallows of a 5-ml bolus of water. There was no significant difference in striated muscle contractions between patients with heartburn and esophagitis and patients with heartburn without esophagitis. There was also no significant difference between patients with heartburn younger or older than 50 years or between men and women or in esophageal striated muscle contractions between patients with heartburn and Chagas' disease. The esophageal proximal amplitude of contractions was lower in patients with idiopathic achalasia than in patients with heartburn. In patients with Chagas' disease there was no significant difference between patients with esophageal dilatation and patients with normal esophageal diameter. Esophageal striated muscle contractions in patients with Chagas' disease have the same amplitude and duration as seen in patients with heartburn. Patients with idiopathic achalasia have a lower amplitude of contraction than patients with heartburn.

Esophageal motor disorders

Esophageal motor function remains of investigative and clinical interest because of its relevance to symptoms and its relation to the occurrence and management of gastroesophageal reflux disease. Refinement in diagnostic methods continues to occur, and improved tests for identifying the nature or severity of motor disturbances in both the proximal and distal esophageal regions are now well described. Controversy concerning the management of achalasia, the best-understood distal motor disorder, is resolving as the benefits and disadvantages of available treatment options are becoming recognized. The relation of esophageal motor dysfunction to outcomes from antireflux surgery remains incompletely understood.

Manometric heterogeneity in patients with idiopathic achalasia

BACKGROUND & AIMS

In certain cases of achalasia, particularly those in early stages with minimal endoscopic or radiographic abnormalities, the diagnosis may rely on manometry, which is the most sensitive test for the disease. The aim of this study was to critically evaluate the manometric criteria in a population of patients with idiopathic achalasia.

METHODS

Clinical histories and manometric recordings of 58 patients with idiopathic achalasia and 43 control subjects were analyzed with regard to esophageal body contraction amplitude, peristaltic effectiveness in terms of both completeness and propagation velocity, lower esophageal sphincter (LES) resting pressure, LES relaxation pressure, and intraesophageal-intragastric pressure gradient. Variants of achalasia were defined by finding manometric features that significantly differed from the remainder of achalasia patients, such that the diagnosis might be questioned.

RESULTS

Four manometrically distinct variants were identified. These variants were characterized by (1) the presence of high amplitude esophageal body contractions, (2) a short segment of esophageal body aperistalsis, (3) retained complete deglutitive LES relaxation, and (4) intact transient LES relaxation. In each instance, the most extreme variant is discussed and compared with the remainder of the achalasia population and with controls.

CONCLUSIONS

The significance in defining these variants of achalasia lies in the recognition that these sometimes confusing manometric findings are consistent with achalasia when combined with additional clinical data supportive of the diagnosis. Furthermore, such variants provide important clues into the pathophysiology of this rare disorder.