Previous studies have demonstrated a cause and effect relationship between standard Stamm gastrostomy (SG) and subsequent gastroesophageal reflux (GER). To further investigate this clinical problem, three additional types of gastrostomy were evaluated in regard to their influence on the lower esophageal high pressure zone (LEHPZ). Twenty-three male cats were entered in the study weighing 2.6 to 3.6 kg. Baseline manometric studies of the LEHPZ were determined after ketamine anesthesia. In group I (n = 9), Witzel gastrostomy was performed over a 12 Fr catheter without fixation of the stomach to the anterior abdominal wall. In group II (n = 7), percutaneous gastrostomy was performed without fixation of the stomach to the anterior abdominal wall. In group III (n = 7), percutaneous gastrostomy was performed but the stomach was firmly fixed to the abdominal wall. LEHPZ pressures were then repeated 2 weeks postoperatively. Mean preoperative LEHPZ pressure for group I was 16.2 +/- 3.72 mmHg, group II was 16.5 +/- 6.91 mmHg, and group III was 18.3 +/- 5.59 mmHg. Mean postoperative pressure for group 1 was 14.7 +/- 4.26 mmHg, group II was 16.5 +/- 5.77 mmHg, and group III was 10.8 +/- 3.97 mmHg. LEHPZ pressure was similar preoperatively and postoperatively in groups I and II but was significantly decreased postoperatively (P less than .01) in group III. Contrast studies demonstrated maintenance of the angle of His in group 1 and II and alteration of the angle of His in group III. Gastrostomy associated with fixation of the stomach to the anterior abdominal wall results in decreased LEHPZ pressures. This predisposes the subject to GER.(ABSTRACT TRUNCATED AT 250 WORDS)