M1114 Evaluation of Gastric Mucosal Blood Flow Using Contrast-Enhanced Ultrasonography During Low-Dose Aspirin Therapy and During NSAID and Low-Dose Aspirin Combined Therapy

Background: Low-dose aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) are now used extensively for prevention of vascular disorders or treatment of chronic pain. The frequency of gastric mucosal lesions is expected to increase with combined use of these medicines. A histamine-2 receptor antagonist (H2RA) suppresses development of acid secretion and is expected to prevent development of gastric mucosal lesions associated with NSAIDs and low-dose aspirin. Evaluation of gastrointestinal blood flow is important for understanding the pathogenesis of various gastrointestinal diseases. Aim: we used a noninvasive examination method, transabdominal contrast-enhanced ultrasonography (low mechanical harmonic index imaging), and assessed gastric mucosal blood flow during low-dose aspirin therapy and combined therapy with low-dose aspirin and an NSAID (loxoprofen) and then investigated the effect of an H2RA (lafutidine) on gastric mucosal blood flow. Subjects and methods: The subjects were sixteen healthy volunteers without H. pylori infection. Their mean age was 24.4 years. Subjects in the placebe took low-dose aspirin (81mg) once a day for 14 days (days 1-14), 60 mg of loxoprofen three times a day for 7 days (days 8-14), and a placebo twice a day for 14 days (days 1-14). Subjects in the lafutidine followed the same protocol for low-dose aspirin and loxoprofen but took 10 mg of lafutidine twice a day for 14 days (days 1-14). We carried out contrast-enhanced ultrasonography with perflubutane on day 1, day 8, day 15 and measured gastric mucosal blood flow of the anterior wall of the gastric antrum. A time-intensity curve (TIC) for gastric mucosal blood flow was plotted from recorded ultrasonographic images. Three values were calculated from the TIC: AUC (area under the curve), TIC peak value and TIC peak time. We used these three values to measure gastric mucosal blood flow. Results: The AUC decreased significantly after taking low-dose aspirin (day 8) in both the placebo and lafutidine groups. However, no statistically significant decrease in the AUC was found between day 8 and day 15. The results for TIC peak value were the same as those for AUC. No significant extension of TIC peak time was shown between day 1, day 8 and day 15. No significant difference in AUC, TIC peak value and TIC peak time was found between the placebo and laftidine groups. Conclusion: Low-mechanical index imaging with perflubutane enables noninvasive assessment of gastric mucosal blood flow in real time. The use of this method in a daily primary care setting is expected to lead to prevention and early detection of gastric mucosal injury caused by aspirin and NSAIDs.