INTRODUCTION: Previous studies with visible light spectroscopy (VLS) and laser Doppler flowmetry (LDF) have shown reduced mucosal circulation of the stomach and duodenal wall in patients with median arcuate ligament syndrome (MALS) and chronic mesenteric ischemia (CMI). However, transserosal microcirculatory assessment during the operative treatment of patients with these conditions has not yet been performed. We aimed to investigate if laparoscopic decompression for MALS and aortomesenteric bypass in CMI can result in immediate measurable increase in the microcirculation in stomach and duodenum. PATIENTS AND METHODS: In a single center, prospective comparative cohort study, twenty-eight patients suspected of MALS, and eleven with CMI underwent assessment of transserosal microcirculation of stomach and duodenum with Visible Light Spectroscopy (VLS) and Laser Doppler flowmetry (LDF), during surgery. Patients with computed tomography angiography (CTA) verified stenosis grade ≥50% in MALS and ≥70% in CMI were included in the study. Duplex ultrasound (DUS) was performed before and after the surgical treatment. The changes in the pre- and postoperative microcirculation were calculated with paired sample RESULTS: VLS showed significant increase in the transserosal relative hemoglobin concentration (rHb) after laparoscopic decompression in patients with MALS (Stomach, before: 58AU±13, after: 62AU±14, p = 0.017) and (Duodenum, before: 62AU±15, after:70AU±15, p = 0.004). Furthermore, a significantly increased blood flow was found in duodenum (Before: 276AU±89, After: 315AU±93, p = 0.015). However, the SaO2 was decreased significantly in the stomach (Before: 86AU±10, After: 82AU±14, p = 0.015), but remained unchanged in the duodenal serosa.The study did not find any increase in the microcirculation of the CMI patients after revascularization. The baseline transserosal microcirculation was indifferent between the groups. CONCLUSION: Laparoscopic decompression leads to enhanced transserosal microcirculation in stomach and duodenum in the patients with MALS. The baseline transserosal microcirculation in stomach and duodenum is indifferent in the MALS and CMI.