A244 AGA ABSTRACTS

1430THE ESOPHAGEAL MUSCLE TffiCKNESS IN PATIENTS WITHHYPERTENSIVE ESOPHAGEAL PERISTALSIS,Ravinder K. Mittal, Nonko D. Pehlivanov, Jianmin Liu, Cheryl S. Beau­mont, Univ of CA, San Diego and San Diego VAMC, San Diego, CA;Univ of CA, San Diego, San Diego, CA.

There is a direct relationship between changes in muscle thickness asdetected by ultrasonography and esophageal contraction amplitude in nor­mal subjects. AIM: to determine the relationship between esophagealmuscle thickness and esophageal contraction amplitude in patients withnutcracker esophagus (NE) (mean esophageal contractions> 180 mm Hg).METHODS: We studied 10 normal subjects and 8 patients with NE.Simultaneous esophageal manometry and high frequency intraluminal ul­trasonography (using a 20 MHz Olympus probe) were performed. Ultra­sound images and esophageal pressures were recorded in the lower esoph­ageal sphincter (LES) and at 2, 4, 6, 8 and 10 em above the LES. Themonitoring was performed in the resting state and during standardizedswallow (WS) induced esophageal contraction (5 WS at each level). Theultrasound images were digitized and the thickness of the muscularispropria (both circular and longitudinal muscle) was measured using animage analysis software. Images corresponding to the time periods beforeswallow induced contraction (baseline) and peak of the contractions wereanalyzed. RESULTS: Muscularis propria in patients was markedly thickercompared to normal subjects, at the LES, as well as at all the esophageallevels, both at the baseline and at the peak of swallow induced contractions.The muscles were thicker at the 2 cm compared tolO cm site in theesophagus. The change in thickness during esophageal contraction wassimilar in patients compared to normal subjects. The correlation betweenthe peak muscle thickness and contraction amplitudes was stronger innormal subjects (r=0.55) compared to the patients (r=0.45). CONCLU­SIONS: The increase in baseline wall thickness is most likely responsiblefor the high amplitude esophageal contractions in patients with nutcrackeresophagus.

Muscularis thickness ofthe esophagus innormal and nutcracker esophagus patients

LES 2CM 4CM 6CM 8CM 10CMBSL PK BSL PK BSL PK BSL PK BSL PK BSL PK

normal 1.95 2.54 1.281 231 1.14 2.14 1.08 2.21 1.07 2.17 1.06 2.05NE 256' 2.9]' 211'1 333' 1.82' 3.10' 1.71' 2.83' 1.55' 252' 1.43' 2.32'

• P<.05 vs. control; t P<.05 vs. 10em. BSL: baseline; PK: peak.

1431COMPARISON OF ESOPHAGEAL MUSCULARIS PROPRIA INPATIENTS WITH DIFFUSE ESOPHAGEAL SPASM ANDHEALTHY SUBJECTS,Ravinder K. Mittal, Nonko Pehlivanov, Jianmin Liu, Univ of CA, SanDiego and San Diego VAMC, San Diego, CA.

Diffuse esophageal spasm (DES) is thought to be due to the impairedinhibitory innervation of the smooth muscles of the esophagus. Autopsystudies show that patients with DES may have hypertrophy of the esoph­ageal muscle. AIM: to compare the esophageal muscle in patients withDES to normal subjects using high frequency intraluminal ultrasonography(HFIU). METHODS: We studied lO normal subjects and 7 patients withDES (defined as: if> 30%, but not all, of the swallow induced contractionswere simultaneous in onset). Simultaneous manometry and HFIU (using a20 MHz Olympus probe) were performed. HFlUS images and pressurerecordings were obtained in the lower esophageal sphincter (LES) and at 2,4, 6, 8 and 10 em above the LES. They were performed in the baseline stateand during swallow induced contractions (5 swallows at each level). TheHFIU images were digitized and the muscularis propria thickness (MPT)(both circular and longitudinal muscle) was measured using an imageanalysis software. Images corresponding to the baseline periods and at thepeak of contractions were analyzed. RESULTS: Esophageal MPT in DESpatients was significantly thicker compared to normals during baseline aswell as at the peak of contractions in the LES as well as at all theesophageal levels tested. The MPT was thicker at the 2 em compared to the10 em site in both groups. The change in MPT during esophageal contrac­tion was not different between the two groups. The correlation between thepeak muscle thickness and contraction amplitudes was stronger in normalsubjects (r=.55) compared to the patients (r=.34). CONCLUSIONS:Patients with DES show thicker distal esophageal muscle compare tonormal subjects. The abnormal muscularis propria may contribute to dys­phasia in DES patients.

Thickness ofmuscularis propria innormal subjects and patients with DES

LES 2em 4em 6em 8em iDemBSL PK BSL PK BSL PK BSL PK BSL PK BSL PK

Normal 1.95 2.54 1.281 2.31 1.14 2.14 1.08 2.21 1.07 2.17 1.06 2.05patient 2.64' 3.30' 2.36'1 3.43' 2.22' 335' 1.84' 2.BO' 1.73' 2.60' 1.50' 2.59'

• P<.05 vs. normal; t P<.05 vs. 10em. BSL: baseline; PK; peak.

GASTROENTEROLOGY Vol. US, No.4

1432SCHATZKI RING: REASONS FOR DELAY IN DIAGNOSIS ANDLONG TERM RESPONSE TO DILATATION.Maree E. Pekin, Ian J. Cook, St George's Hosp, Kogarah NSW, Australia.

A lower Schatzki ring is a common cause of solid food dysphagia. Patientsare often symtomatic for many years before diagnosis. From a patientdatabase, prospectively collected by one clinician from 1992 - 1998, therewere 53 patients with a Schatzki ring; 51 of whom presented with dyspha­gia and in 10 of these dysphagia was attributable to another cause. In theremaining 41 patients in whom dysphagia was attributable to the ring, theaverage duration of symptoms prior to diagnosis was 6.4 years (range 0.1- 27 yrs). The site of reported bolus hold up was cervical in 14, midretrostemal in 14 and low retrostemalin13patients.Prior to referral to StGeorge Hospital, 37 barium swallows had been performed in 31 of the 41symptomatic patients. The ring was demonstrated radiologically in only 9of these 31(29%). However, in all but one case, prone views of the distaloesophagus were either not performed (5) or not reported (25) by theradiologist. Following referral, repeat barium swallows in 15 patients,including prone views where necessary 01, NS in 4) demonstrated the ringin another 7 patients. Hence, a barium swallow was diagnostic in a total of16 of 31 (52%) patients with symptomatic rings. An endoscopic diagnosishad been made prior to referral in 3 of 18 07%) patients who hadundergone a total of 28 gastroscopies. Of the 40 undergoing repeat endos­copy, the ring was seen in 26 (65%). In a further 5 patients, a ring wasinferred from the appearance of a squamo-columnar mucosal tear imme­diately following dilatation raising the endoscopic diagnostic sensitivity to78%. In 36 of 40 patients who underwent dilatation follow up data wasavailable. 34 of 36 (94%) had immediate resolution of symptoms followingone dilatation and 100% after repeat dilatation in the remaining 2. Cumu­lative dysphagia recurrence rates requiring repeat dilatation were: 8 (20%)at 1 year, 9 (23%) at 2 years, 14 (35%) at 3 years. We conclude: I. Amucosal ring is a common incidental finding in the dysphagic patient; 2. Anormal barium swallow and normal endoscopy does not preclude a diag­nosis of Schatzki ring causing dysphagia but may contribute to delay indiagnosis; 3 Diagnostic sensitivity of radiology is only 52% and endos­copy is 65%; 4. Symptom recurrence is high necessitating repeat dilatationin one third at 3yrs.

1433PREVALENCE AND RADIOLOGIC FEATURES OF THE LOWERESOPHAGEAL MUSCULAR RING,Trung Pham, Christian Stevoff, Ikuo Hirano, Northwestern Memorial HospI Northwestern Med Sch, Chicago, IL.

Objective: The lower esophageal muscular ring is a poorly defined entitycompared to the well recognized Schatzki's, or mucosal, ring. The purposeof this study is to report on the radiographic prevalence and features ofmuscular rings. Methods: All upper GI studies and barium swallowsperformed at Northwestern Memorial Hospital between March 1999 andOctober 1999 were reviewed. Muscular rings were defined radiographi­cally as broad, smooth narrowings at the upper end of the esophagealvestibule, with variable caliber that often disappeared completely withesophageal distension. Studies with muscular and mucosal rings werecompiled with the accompanying radiology reports for study indications,symptomatology, and radiologic diagnoses. Measurements are reported asmean ::!: standard deviation. Significance was determined by Student's ttest. Results: 506 radiographs were reviewed. Study indications includedabdominal pain (31%), dysphagia 09%), gastroesophageal refluxlheart­bum 00%), inflammatory bowel disease (7%), anemialGI bleed (5%),diarrhea (4%), nausealvomiting (3%), obstruction (3%) and miscellaneous08%). Eleven (2.2%) muscular rings and 21 (4.2%) mucosal rings wereidentified. Ten of the 19 mucosal rings were identified on the radiologyreports while none of the muscular rings were noted. Patients with mus­cular rings had a mean age of 66 :!: 12 years, while those with mucosalrings had a mean age of 59 ::!: 14 years. Nine of the 11 patients (82%)identified with muscular rings had associated hiatal hernias. compared to20 of the 21 patients (95%) with mucosal rings. 36% of muscular ringpatients had complaints of dysphagia, compared to 21% of mucosal ringpatients. The muscular ring thickness was 9.9 ::!: 3.6 mm, with a maximumdiameter of 21.4 :!: 7.4 mm, a minimum diameter of 5.3 ::!: 4.9 mm, and alocation of 39 :!: 15 mm above the diaphragm. The mucosal ring thicknesswas 4.4 :!: 1.5 rnm, with diameter of 22.6 ::!: 5.9 mm, and location 33 ::!: 14mm above the diaphragm. The differences between the thicknesses andminimum diameters of the mucosal and muscular rings were statisticallysignificant (P<0.05). Conclusions: Although uncommon, the lower esoph­ageal muscular ring is an underrecognized entity. Muscular rings occurabout half as frequently as mucosal rings. Thickness and minimal luminaldiameters of muscular rings compared to mucosal rings are importantcriteria in differentiating the two types of rings. This distinction is impor­tant given differences in their presentations and treatments.