Paradox of gastric cardia – it becomes more acidic following meals while the rest of stomach becomes less acidic

Alan T Clarke ¹, Angela A Wirz ¹, John P Seenan ¹, Jonathan J Manning ¹, Derek Gillen ¹ and Kenneth EL McColl ^1*

¹ University of Glasgow, Western Infirmary, United Kingdom

^* To whom correspondence should be addressed. E-mail: k.e.l.mccoll{at}clinmed.gla.ac.uk.

Accepted 25 November 2008

Abstract

Introduction: The proximal cardia region of the stomach has a high incidence of inflammation, metaplasia and neoplasia. It demonstrates less acid buffering following meals than the more distal stomach. We employed novel high definition pHmetry to investigate acidity at the cardia under fasting conditions and in response to a meal.

Methods: 15 healthy subjects were studied. A custom made 12 electrode pH catheter was clipped at the squamo-columnar junction with 4 electrodes recording proximal to and 8 distal to the squamo-columnar junction. The most distal pH electrode was located at the catheter tip and 9 electrodes in the region of the squamo-columnar junction were 11mm apart.

Results: The electrode situated in the cardia 5.5mm distal to the squamo-columnar junction differed from all other intragastric electrodes during fasting in recording minimal acidity (pH<4 = 2.2%) while all other intragastric electrodes recorded high intragastric acidity (pH<4 = >39.%)(p<0.05). The cardia also differed from the rest of the stomach showing a marked increase in acidity in response to the meal (from 2.2% fasting to 58.4% at 60-70min after meal; p<0.05) while the electrodes distal to the cardia all showed a marked decrease in acidity (p<0.05). These changes in acidity at the cardia following the meal caused the gastric acidity to extend 10mm closer to the squamo-columnar junction.

Conclusion: Whereas, the rest of the stomach shows a marked fall in acidity on ingesting a meal, the cardia paradoxically increases in acidity to become the most acidic region throughout the postprandial period.