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The Gastroesophageal Flap Valve

1999; Lippincott Williams & Wilkins; Volume: 28; Issue: 3 Linguagem: Inglês

10.1097/00004836-199904000-00002

1539-2031

Lucius D. Hill, Richard A. Kozarek,

Dysphagia Assessment and Management

The normal antireflux barrier located at the gastroesophageal junction (GEJ) is a highly competent barrier to reflux of gastric content into the esophagus. The components of this barrier have been studied for many years. The lower esophageal sphincter (LES) has been cited as the most important component of the barrier. Increasing interest has been shown in the contribution to the closing mechanism of the crural fibers of the diaphragm. Although the gastroesophageal flap valve (GEV) was described years ago, it has received little attention and in fact was previously not depicted in a recognized anatomy book. Following the presentation of our work in England, Gray's Anatomy has now included a section on the "gastroesophageal flap valve" (Fig. 1).FIG. 1: The acute angle between the oesophagus and the upper part of the cardia (the angle of His or cardiac incisure) is extended within the lumen as a large fold. It has been proposed as a mechanism additional to the lower oesophageal sphincter limiting oesophageal reflux of gastric fluids. The various operations currently utilized in these patients accomplish this goal by reducing any hiatal hernia back into the abdominal cavity and rebuilding a functional flap valve mechanism.Dr. Qais Qutub Contractor and associates have published a study now on "Endoscopic Esophagitis And Gastroesophageal Flap Valve," which confirms our work. This well-written report from the King Fahad Hospital in Saudi Arabia emphasizes that grading the GEFV correlates better with the patient's reflux status than does measurement of the LESP. In our study in the cadaver, there was a gradient at the junction of the stomach and the esophagus. Since there is no sphincter pressure in the cadaver, it was concluded that the gradient was the result of the flap valve. This flap valve consisted of a musculomucosal fold created by the angle of entry of the esophagus into the stomach, and extended 3 to 4 cm along the lesser curve. The gradient of the GEJ was increased when the valve was lengthened surgically. This was done without raising the pressure in the LES. The extensive observations in the cadaver confirmed the presence of the flap valve. This led to the second portion of the study: inspection of the GEJ from below by a retroflexed endoscope. At surgery the GEV has been viewed through a gastrostomy performed in patients, both for visualization of gastric lesions and during gastric resection. The valve appears as a 180-degree musculomucosal fold extending along the lesser curvature for 3 to 4 cm. These findings led to the visualization of the valve through the retroflexed endoscope. In the preliminary group of normal subjects and patients with reflux a clear difference was seen in the appearance of the GEJ as seen from below with the retroflexed endoscope. These differences allowed for the development of a grading system. In control subjects there was a prominent fold of tissue along the lesser curvature that was closely apposed to the endoscope through all phases of respiration. This appearance was assigned Grade I (Fig. 2). Less commonly, the fold was present but was not as prominent and there were periods of rapid opening and closing around the endoscope. This was assigned Grade II (Fig. 3). In contrast, in reflux patients the fold was not prominent and the endoscope was not tightly gripped by the tissue. A hiatal hernia was present in nearly all of the patients. This was assigned Grade III (Fig. 4). Patients with reflux and a large hiatal hernia had essentially no fold, and the lumen of the esophagus was wide open allowing the squamous epithelium to be viewed from below (Grade IV, Fig. 5).FIG. 2: Grade I flap valve. Note the ridge of tissue, which is closely approximated to the shaft of the retroflexed endoscope. It extends 3 to 4 cm along the lesser curve.FIG. 3: Grade II flap valve. The ridge is slightly less well defined than Grade I and it opens rarely with respiration and closes promptly.FIG. 4: Grade III flap valve. The ridge is barely present, and there is often failure to close around the endoscope. It is nearly always accompanied by a hiatal hernia and esophagitis.FIG. 5: Grade IV flap valve. There is no muscular ridge at all. The gastroesophageal area stays open all the time, and squamous epithelium can often be seen from the retroflexed position. A hiatus is always present as is esophagitis.Videotapes from these patients were coded and displayed to two surgeons and three gastroenterolgists, who had no previous experience observing the valve; there was agreement in grade between four of five observers in 80% of the cases. Even when still photographs were graded, the same degree of agreement was present. Disagreement was never more than one grade and usually occurred when trying to decide between Grades I and II and between Grades III and IV. Therefore it was decided to categorize Grades I and II as normal in appearance, and Grades III and IV as a reflux appearance. These criteria were then applied to a prospective cohort of 44 patients undergoing endoscopy for clinical reasons by one endoscopist who was blinded to the patient's reflux status. In this group of patients grading of the valve predicted the patient's reflux status in 41 of the 44 patients, whereas measurement of the LES pressure alone predicted the status correctly in only 17 of the patients. We concluded from extensive studies that grading of the GEV correlates better with the patient's reflux status than measurement of the LES pressure. Dr. Contractor, at the King Fahad Specialist Hospital in Saudi Arabia, reports a series of carefully performed studies that confirms our finding. Dr. Contractor states that the frequency of an abnormal GEFV was significantly more common in patients with symptomatic GER with esophagitis as compared to controls. This indicates that abnormality of GEFV has a direct relationship to the severity of GERD. There are differences from our findings in that we did not see esophagitis with a true Grade I GEFV. The valve must be observed through all phases of respiration. If the valve opens with respiration, then reflux leading to esophagitis may occur. We are now carrying this a step further: with patients who give a history of upright reflux, we actually sit the patient up during endoscopy. We have noted that the valve disappears in patients with upright reflux. We are in the process of publishing these data. Our findings are in complete agreement with Dr. Contractor's group, which has documented that with Grades III and IV esophagitis occurs and does not occur with a Grade I to II GEV. We found that esophagitis of any degree was very rare in patients with a Grade I to II GEV valve. Another of their findings that is puzzling is that there was no esophagitis in 16 patients with Grades III and IV GEV. In the true Grades III and IV valve the esophagus has very little protection against reflux, and we found esophagitis to be consistent in nearly all of these patients. With further experience these minor differences should be reconciled; the important conclusion that advanced esophagitis does not occur with a Grade I or II valve is the significant finding. The sphincter and the valve work together and form a powerful deterrent to reflux in the normal situation. If the valve gives way, the sphincter usually gives way. This is not always true. When the stomach slides up into the posterior mediastinum, the valve may be retained and the patient may show little or no reflux. Usually, however, with a sliding hernia the valve and the sphincter are both lost. The relationship of the LES and the GEFV are shown in Fig. 6. The sphincter resides in the valve and they work together. The arrows indicate that increased intragastric pressure closes the GEFV against the lesser curve, increasing the efficiency of the valve.FIG. 6: The sphincter resides in the valve and they work together. The arrows indicate that increased intra-gastric pressure closed the GEFV against the lesser curve, increasing the efficiency of the valve.Now that these findings have been confirmed not only by Gray's Anatomy, but also by institutions on opposite sides of the globe, it is time for endoscopists to record what they see every time they perform an endoscopy. It has been puzzling to us that the endoscopist sees the valve every time he or she performs an endoscopy in a patient, and yet appears to be reluctant to describe a finding which is extremely helpful in the management of gastroesophageal reflux disease (GERD). Dr. Contractor is in agreement with us that retroflex grading of the GEV adds little time to the endoscopy and adds no cost to the procedure, and yet gives the endoscopist a powerful tool to correctly diagnose the patient's status with GERD. The appearances are easily learned, and agreement between observers is quite good. We believe that assessment of GEFV will be a useful addition to the armamentarium of the endoscopist. Lucius D. Hill, M.D. Richard A. Kozarek, M.D.