Comparison of hemodynamic stress in healthy vessels after parent artery occlusion and flow diverter stent treatment for internal carotid artery aneurysm.

OBJECTIVE: De novo aneurysms generally develop in healthy vessels after parent artery occlusion for large internal carotid artery (ICA) aneurysm, possibly owing to increased hemodynamic stress in the remaining vessels. In recent years, there has been a shift toward flow diverter stent treatment. However, there is a lack of direct evidence and data that prove this change in hemodynamic stress in healthy vessels after parent artery occlusion and flow diverter stent treatment. The authors compared hemodynamic stress in healthy-side vessels before and after parent artery occlusion and flow diverter treatments. METHODS: The authors included patients who underwent 3D cine phase-contrast MRI before and after large ICA aneurysm treatment. Spatially and temporally averaged volume flow rates and spatially averaged systolic wall shear stress (WSS) in healthy-side ICA distal to the posterior communicating artery (C1 segment according to Fisher's classification) were measured before and after parent artery occlusion and flow diverter treatments. RESULTS: Seventeen patients were included (5 patients in the parent artery occlusion group and 12 in the flow diverter group). At 1-2 months after treatment, median volume flow rate in healthy-side ICA increased from 5.36 ml/sec to 6.28 ml/sec (total increase 117%, p = 0.04) in the parent artery occlusion group and from 4.65 ml/sec to 4.93 ml/sec (total increase 106%, p = 0.02) in the flow diverter group. In the parent artery occlusion group, median WSS in the C1 segment of the healthy-side ICA increased from 3.91 Pa to 5.61 Pa (total increase 143%, p = 0.08); however, no significant increase was observed in the flow diverter group (4.29 Pa to 4.57 Pa [total increase 107%, p = 0.21]). CONCLUSIONS: Postoperatively, volume flow rate and WSS in the C1 segment of the healthy-side ICA significantly increased in the parent artery occlusion group. Therefore, the parent artery occlusion group was more prone to de novo aneurysm than the flow diverter group.

Heterotopic pancreatitis: gastric outlet obstruction due to an intramural pseudocyst and hamartoma.

Heterotopic pancreas, usually a silent gastrointestinal malformation, may become clinically evident when complicated by chronic inflammation. We report a case of pancreatitis and extensive pseudocyst formation in the gastric antrum, which caused gastric outlet obstruction. The diagnosis was obscured by a history of emesis during pregnancy and a previously resected gastric polyp. The nature of the obstructive lesion was not diagnosed preoperatively in spite of endosonographic evaluation. Intraoperatively, a cystic tumor of the stomach wall was found, the lesion was excised, and a pyloroplasty was performed to close the excision site. Histology revealed heterotopic pancreatic tissue with chronic inflammation, fibrosis and pseudocyst formation and adjacent to this lesion a myoglandular hamartoma. The patient is symptom-free two years after surgery and no recurrence was found. The nature of heterotopic pancreatic tissue, its diagnosis and management are discussed.