MALS was first described in 1963 as a syndrome attributed to compression of the celiac artery by the MAL [
4]. Although typical symptoms include epigastralgia, anorexia, and weight loss, most patients with a stenosed celiac artery caused by the MAL are asymptomatic. More recently, MALS (or compression of the celiac artery by the MAL) has attracted interest in relation to pancreaticoduodenal artery (PDA) aneurysms. Some authors have described the hemodynamic mechanisms of aneurysmal formation in the collateral vessels between the celiac artery and the SMA; that is, in the presence of compression in the celiac artery, the shear stress on the collateral vessel walls increases remarkably [
5]. Once a PDA aneurysm is diagnosed, it should be treated promptly as ruptured aneurysms are life-threatening and the risk of rupture is not related to the size of the aneurysm [
3].
The present report describes a case of a ruptured RGA aneurysm with MALS. The formation of an aneurysm in the gastric artery is rare [
1]. Although the etiology is unclear, the main causes of gastric aneurysm are said to be atherosclerosis, trauma, and inflammation [
6]. The present case did not display any of those causes; instead, we suppose the MAL played an important role in the development of this rare RGA aneurysm. In this case, the formation of a RGA aneurysm can be attributed to the increased stress on the vessel walls. Thus, the management of this patient with a ruptured RGA aneurysm and MALS should be the same as that for any patient with a PDA aneurysm and MALS. There are two proposed alternatives for the treatment of PDA aneurysms (embolization or resection), but the necessity for treatment of the stenosed celiac artery remains uncertain. Some authors have reported that celiac artery reconstruction might not be necessary given that no patients have developed organ ischemia or relapse of the aneurysm after coil embolization alone [
7,
8]. However, the follow-up periods in these reports were not long enough to draw a firm conclusion, as was acknowledged by the authors. On the other hand, there are some authors who do think that revascularization or decompression of the celiac axis is necessary to prevent the possibility of recurrence of the aneurysms [
9,
10]. Takase et al. reported that the follow-up period should be more than 10 years to allow the formation of new aneurysms if they are to occur; this is because they found that there was an approximately a 10-year difference in age between MALS patients with aneurysms and those without aneurysms [
10]. Other reports showed that simple reconstruction of the celiac trunk led to complete aneurysm regression [
11‐
13]. Furthermore, Mano et al. reported increasing stress on the vessel walls of the pancreaticoduodenal arcade in patients with PDA aneurysms with celiac artery occlusion [
5]. These reports support the hypothesis that the MAL can independently cause aneurysm formation. They also emphasize the importance of revascularization of the celiac axis. Normalization of celiac blood flow can treat the aneurysm and prevent the formation of new aneurysms. In fact, an intraoperative aortogram before MAL transection revealed blood flow coming from the SMA via the common hepatic artery to the RGA aneurysm. Similarly, a dilated DPA was the major collateral vessel feeding the splenic artery, instead of antegrade flow through the celiac artery. If we simply resected or excluded the RGA aneurysm, the shear stress on collateral vessels such as the DPA would increase, possibly forming new aneurysms in the long-term. The findings on follow-up CT 18 months after surgery showed an enlarged celiac artery (from 3.5 mm to 5 mm in diameter) and narrowed DPA without any new aneurysm development, supporting our speculation that normalization of the celiac blood flow decreased shear stress on the collateral vessels. Nevertheless, we declare the limitation in this case report that there were no objective findings such as direct blood pressure before and after the celiac revascularization, and ideally in the long term to verify the hemodynamic evidence of our discussion. Further follow up is necessary to determine the possible recurrence of aneurysms in this patient.
In conclusion, the present report described a rare case of a ruptured RGA aneurysm in a patient with MALS. Blood flow to the common hepatic artery from the SMA might be a causative factor for this exceptional aneurysm formation in the RGA as a result of the changed hemodynamic environment. While the necessity of the celiac artery revascularization could be questioned, the present case suggested the potential benefit of MAL transection to decrease the shear stress on the collateral vessels, which are otherwise prone to the formation of new aneurysms.