YIELD PRESSURE, ANATOMY OF THE CARDIA AND GASTROESOPHAGEAL REFLUX

The yield pressure at which the cardia opens in response to gastric di stension was measured in 155 subjects with and without gastro-oesophag eal reflux (GOR) and after Nissen fundoplication. Yield pressure was m easured by endoscopy or during oesophageal manometry. The median press ure was significantly lower in subjects with GOR than in those without (P < 0.0001). After successful Nissen fundoplication this pressure in creased to supranormal values (P < 0.0001). There was a close relation ship between yield pressure and the presence and size of hiatus hernia and also between yield pressure and the valvular appearance of the ca rdia at endoscopy. There was a significant correlation between yield p ressure. and oesophageal acid exposure. However, no relationship was o bserved between yield pressure and lower oesophageal sphincter pressur e or intra-abdominal length. These results suggest that yield pressure is useful for assessment of the competence of the cardia, particularl y after antireflux surgery. The competence of the cardia is greatly in fluenced by its anatomical structure.