Simplifying the evaluation of postprandial antral motor function in patients with suspected gastroparesis

Objectives: Antral hypomotility is associated with symptoms of gastric stasis[fnc,l. Aims: To quantitate antral motor function in patients with suspected gastroparesis due to idiopathic or secondary hypomotility; and to determine whether there are simpler indices to assess antral motility. Methods: Standard eight-lumen antroduodenal manometry was performed in 67 patients for 3-h fasting and 2-h postprandial measurements. Antral motility 1 cm proximal to the pylorus was quantitated for a 2-h fed period as an index: MI = In[(number contractions x (amplitudes) + 1]. Fifteen healthy volunteers served as controls. Results: Forty-one patients had hypomotility and 26 normal antral motility, defined by a MI ≤ 13.67. Patients with antral hypomotility due to a neuropathic (n = 17) or myopathic (n = 3) disorder showed a significantly lower MI (11.6 ± 0.3 [SEM]; 95% confidence interval 11-12.1)compared with patients with idiopathic hypomotility (n = 21, MI = 12.5 ± 0.2). There were fewer antral contractions postprandially in patients with secondary hypomotility than in idiopathic hypomotility (66 ± 6 per 2 h vs 90 ± 10; p < 0.05), and both were lower than in healthy controls (224 ± 15). Mean amplitudes of antral contractions were similar for the neuropathic, idiopathic and control groups, but lower in myopathic (33 ± 6 mm Hg) compared with neuropathic disorders (48 ± 4 mm Hg; fifth percentile 30.6 mm Hg). Conclusions: An antral MI < 12.1 should lead to a search for an underlying neuropathic or myopathic process; an average of less than 1 contraction per minute postprandially is a simple estimate of significant hypomotility. Antral contractions with a mean amplitude < 30 mm Hg suggest a myopathic disorder.