2023 Volume 50 Issue 2 Pages 137-141
The patient was a 58-year-old male. He was admitted to our hospital with anorexia, weight loss (-10 kg/2 months), and repeated vomiting after radiofrequency catheter ablation (RFCA) for atrial fibrillation. Abdominal CT showed marked gastric dilatation and partial dilatation and collapse of the third portion of the duodenum. Since a part of the third portion of the duodenum was compressed by the superior mesenteric artery (SMA) and the aorta (Ao), we diagnosed SMA syndrome. Ultrasonography utilizing positional changes revealed that the distance between the SMA and Ao varied from 6.0 mm in the supine position, 40.1 mm in the left lateral recumbent position, 30.8 mm in the right lateral recumbent position, and 7.7 mm in the sitting position, with duodenal compression being reduced most in the left lateral recumbent position. After hospitalization and instruction in mosapride citrate administration, divided meals, and left-side supine position after meals, his symptoms including vomiting resolved.The patient was discharged from the hospital without any symptoms. Recently, RFCA for atrial fibrillation has been pointed out as a cause of SMA syndrome, in which the ablation energy from RFCA is radiated outside the heart and damages the perigastric vagal plexus, resulting in gastric peristalsis, anorexia, and weight loss, which causes SMA syndrome. In the present case, the peri-SMA intestinal tract was observed with positional ultrasonography, which allowed real-time observation of the opening of the duodenal stenosis as the SMA was greatly displaced in the left lateral recumbent position. Ultrasonography utilizing positional changes is useful for diagnosis of SMA syndrome and identification of the optimal position for prevention of the onset of this syndrome.
