The clinical manifestations of CACS include the triad of postprandial pain, nausea/vomiting, and weight loss [2]. In our present study, the postprandial pain is the most common symptom in all patients. However, these symptoms are usually nonspecific and are easily misdiagnosed as functional dyspepsia, peptic ulcer disease, or gastropathy. Patients will not present with symptoms if compensated well via the collateral vessels or the blood flow is sufficient to handle demands. There are two main theories used to explain the pathogenesis of the symptoms. The first theory is mesenteric ischemia arises either from direct foregut ischemia or, alternatively, through postprandial steal via collaterals from the superior mesenteric artery to the celiac bed, leading to midgut ischemia [16]. The second theory is neurogenic stimulation caused by direct compression of the celiac ganglion and plexus, leading to splanchnic vasoconstriction or via direct sympathetic pain fiber irritation [17].

Although CACS and SMAS are two rare different disorders with an uncertainty of pathogenesis, they share similar clinical symptoms. However, their association was seldom studied in the literature. Sianesi et al. reported 59 patients affected by CACS and 28 by SMAS [18]. The coexistence of both syndromes in 8 patients was observed in their study. In our present study, we identified the coexistence of CACS and SMAS in 64% of all patients. Based on our experiences in the current study, we hypothesize that CACS may be a rare etiology of SMAS because of the mesenteric ischemia of CACS can induce the weight loss of patients and result in the formation of SMAS.

The diagnosis of CACS is usually based on typical clinical symptoms with radiological imaging. Lateral view aortography had been thought to be a golden standard modality in diagnosing CACS [19]. However, it is invasive, expensive, and time consuming. Moreover, CACS may be misdiagnosed if only an anterior-posterior view is obtained. Scholbach reported that color Doppler ultrasound might be a powerful tool for CACS screening [20]. However, its role in diagnosing CACS is still controversial because of the influence of iatrogenic factors and the high degree of dependence on the technicians' ability and experience. Recently, multidetector CTA with proper 2D or 3D postprocessing techniques has become a more favorable modality in diagnosing vascular diseases, including CACS and SMAS [21, 22]. CTA can demonstrate the presence and degree of stenosis of the celiac artery and SMA, the collateral circulation, relationships between vessels and adjacent tissues, and excluding other causes of vascular obstruction. The classical findings of CACS in CTA include thickened MAL, asymmetrical, and respiratory-dependent stenosis of proximal celiac artery with poststenotic dilatation, hooked appearance of celiac artery with indentation of adjacent aorta [21]. In addition to the radiological imaging, a functional test ideally should be present to prove the presence of mesenteric ischemia. Currently, only PC2 tonometry or visible light spectroscopy has been validated [23].

In the treatment of CACS, there were a number of surgical approaches and endovascular therapies outlined in the literature. Conventional open surgery (either transabdominal by median laparotomy or retroperitoneal by left subcostal incision), including division of the MAL and/or resection of periarterial neurofibrotic tissue, is usually adequate in most patients [2, 24]. Moreover, some authors suggested additional arterial reconstruction of the entrapped celiac artery by primary reanastomosis, interposition grafting, or bypass to offer better outcome [25, 26]. The average rate of being symptom-free is around 70–80% after successful surgery based on long-term followup [26]. Although the success rates of open surgery on vascular patency are excellent, the operative trauma to the abdominal wall and cavity is extensive. Recently, laparoscopy is considered a novel approach for the treatment of CACS. In 2000, Roayaie et al. performed the first laparoscopic release of CACS [27]. In 2009, Baccari et al. reported a case series study, in which 14 of 16 patients remained symptom-free in the followup after laparoscopic approach [28]. Moreover, van Petersen et al. first applied an endoscopic retroperitoneal approach instead of an abdominal endoscopic approach for the release of the celiac trunk in CACS [29]. The reason was that retroperitoneal method can visualize the complex local anatomy more distinctly. The laparoscopic approach has the advantage of being less invasive but equally effective for decompressing the entrapped celiac artery. Moreover, it avoids the morbidity of an upper-midline laparotomy and shortens hospital stay, resulting in early refeeding [30]. Although there are more patients with CACS receiving the laparoscopic approach, there is potential risk of vascular injury through using the method such as our patient 12, and adjunctive celiac artery intervention is often required. Therefore, surgical approaches, both laparoscopic and open, can be safely performed with minimal morbidity and mortality. Endovascular therapies for revascularization of celiac artery by PTA with either balloon dilatation or stent implantation have been reported in the literature [31–33]. Furrer et al. first reported PTA in treating mesenteric ischemia in 1980 [31]. In reports thereafter, almost all patients were free of symptoms immediately after the intervention. However, the recurrence rate was high, and the duration of being symptom-free was relatively short. Hence, PTA and stenting in treating CACS are usually unsuccessful because the extrinsic pressure on the celiac artery (the surrounding fibrotic tissue or MAL) will result in the slippage of the stent and/or damage to their material. Prior surgical decompression followed by consolidation of stent implantation is optimal [33]. Therefore, endovascular therapy could play a role of adjuvant therapy or bridging to surgery in treating CACS. In our study, surgical and endovascular treatments were seldom performed in patients with CACS. Only three patients underwent invasive treatment in our present study. The main reason is not enough of an understanding of this disease for most surgeons and gastroenterologists. Patient 1 underwent PTA therapy but had poor response. Patient 2 underwent open laparotomy and had a favorable outcome. CTA demonstrated no stenosis of celiac artery in the postoperative followup. Patient 12 underwent laparoscopic resection of periarterial fibrotic tissue initially; however, it was converted to open surgery due to vascular injury. She had recurrent symptoms 3 months later after operation. In contrast, conservative medical treatment usually has no satisfactory benefits for CACS as in our study.