A structurally intact and competent lower esophageal sphincter in the experimental model shortens and becomes incompetent during gastric distention. The aim of this study was to evaluate postprandial reflux as an indirect measure of this volume-induced sphincter shortening and incompetency. Reflux (pH <4) in the 2-hour period following a meal was retrospectively analyzed from the 24-hour esophageal pH recordings of 94 healthy volunteers and 609 symptomatic patients. Forty-six percent of patients had pathologic postprandial reflux (>95th percentile of normal). The prevalence was lower in patients with a structurally intact compared to a defective lower esophageal sphincter (32% vs. 58%; P <0.001). Pathologic postprandial reflux was greater in patients with abnormal compared to normal findings on 24-hour pH study (76% vs. 21%; P <0.001). Patients with a normal 24-hour pH study and postprandial reflux had shorter sphincter lengths (2.33 vs. 2.82 cm; P <0.001) and lower pressures (10.78 vs. 14.24 mm Hg; P <0.005). A hiatal hernia increased the prevalence of postprandial reflux (P <0.001) in all patients (67% vs. 38%) and in the subgroup with a structurally intact sphincter (75% vs. 27%, P <0.001). Postprandial reflux is a dynamic indicator of sphincter competency, and increases as the structural sphincter characteristics deteriorate and is augmented by a hiatal hernia.

The cause of foregut symptoms is often quite uncertain until a comprehensive evaluation has been performed. The critical elements of this evaluation include historic, radiographic, endoscopic, and physiologic data, and most importantly, the insight of a mature diagnostician. Patients who are not evaluated in a comprehensive way are at risk for serious postoperative problems; surgeons who perform interventions without appropriate diagnostic support may have to deal with these unhappy patients. In the long run, a complete workup provides the guidance for treatment and is cost-effective.