Revascularization of superior mesenteric artery occlusion via the arc of Buhler: A case report and literature review

Introduction

Stenosis or occlusion of the superior mesenteric artery (SMA) leads to chronic intestinal ischemia and hypoxia, resulting in intestinal mucosal injury, possible intestinal necrosis, and even death. This disease has an insidious onset with atypical early symptoms, making diagnosis difficult and compromising timely and optimal treatment planning. Delayed treatment can lead to severe consequences. ¹ Therapeutic SMA stenosis or occlusion approaches include percutaneous endovascular reconstruction, bypass surgery, and hybrid surgery.^2,3 Endovascular treatment has become the preferred first-line therapy for SMA ischemic diseases caused by arterial stenosis due to its safety and efficacy. ⁴

Case report

A 62 year-old female presented with 1 month of recurrent abdominal distension and postprandial pain, which was especially severe after meals, located around the umbilicus. She had experienced a weight loss of 15 kg over 2 months and went to the emergency department, where she was admitted for treatment. She took both enteric-coated aspirin (100 mg/day) and clopidogrel (75 mg/day). She denied any history of atrial fibrillation. She also denied other chronic illness. No smoking, alcohol use, or any other factors that could cause abdominal pain were identified. Computed tomography angiography (CTA) conducted at an outside hospital revealed ostial occlusion of the SMA with distal perfusion via the Arc of Buhler, and severe calcification of the proximal abdominal aorta (Figure 1). On admission, her physical exam revealed the following: tenderness in the lower abdomen without rigidity or rebound, and no abdominal mass. Lab tests returned results within normal ranges, any other potential causes of abdominal pain were excluded. After obtaining informed consent, the procedure was scheduled.OPEN IN VIEWER

The plan was to perform percutaneous SMA revascularization via access through the left brachial artery. Due to the nearly occluded SMA origin and severely calcified abdominal aorta, it was predicted that antegrade wiring could be difficult, so retrograde access via the Arc of Buhler would be attempted if needed. Open surgical bypass would be considered if endovascular revascularization failed. Left brachial arterial access was obtained with a 5F short sheath (Cordis, Miami Lakes, FL). Visceral angiography showed the proximal SMA was occluded without a visible stump. The sheath was upsized to a 6F, 90 cm sheath (Cook Medical, Bloomington, IN). A 5 F single curve catheter (Cordis) and 0.035 hydrophilic wire (Terumo, Somerset, NJ) were advanced into the abdominal aorta. Despite multiple attempts, the SMA ostium could not be wired based on pre-procedural celiac trunk measurements. The single curve catheter was positioned in the celiac trunk and angiography demonstrated retrograde SMA fill via the Arc of Buhler with complete SMA ostial occlusion. A microcatheter and a 0.014 wire (Cordis) were retrogradely passed through the celiac trunk, Arc of Buhler, and the distal end of the superior mesenteric artery, and passed through the occluded segment of the superior mesenteric artery (Figure 2). The right femoral artery was accessed, a 5F sheath was placed, and the wire was captured from the right groin using a snare device. A 7 F guide catheter was introduced, connected to a Y-adaptor, and angiography confirmed positioning in the abdominal aorta with no visible SMA origin. A 3 mm × 40 mm balloon (Boston Scientific, Natick, MA) was inflated across the SMA lesion. Subsequent angiography revealed antegrade flow through the SMA, and a 0.018 guidewire was exchanged to reach the distal end of the SMA via the lesion segment through the femoral artery. A 6.0 mm × 24 mm balloon-expandable bare-metal stent (Hippocampus) was deployed at the occlusion. The final angiography showed a widely patent SMA without residual stenosis (Figure 3).OPEN IN VIEWER

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Figure 3.

The wire was captured from the right groin. The SMA was not visible in the catheter angiography. A 3 mm × 40 mm balloon was inflated across the SMA lesion (yellow arrow). A 6.0 mm × 24 mm balloon-expandable stent was deployed at the occlusion (blue arrow).

The patient had complete symptom relief post-procedure. Dual antiplatelet therapy was prescribed for 6 months, followed by lifelong aspirin. Twelve-month follow-up CTA showed a patent SMA with no stent abnormalities (Figure 4).OPEN IN VIEWER

Discussion

The celiac trunk, SMA, and inferior mesenteric artery (IMA) are the major sources of blood supply to the intestines, with atherosclerosis being the predominant cause of stenosis or occlusion of these vessels. ⁵ SMA stenosis or occlusion can lead to chronic mesenteric ischemia (CMI), commonly presenting as postprandial abdominal pain and progressive weight loss due to intestinal hypoperfusion . ⁶ However, CMI may also progress to fatal bowel infarction. Treatment of CMI is warranted in the presence of symptomatic intestinal ischemia. Medical management focuses on relieving symptoms of CMI by improving microcirculation and anticoagulation. However, open surgical and endovascular revascularization are the most effective treatments for restoring SMA flow.

The main drawbacks of open surgical repair are the substantial trauma and high incidence of perioperative complications. In recent years, with advancements in endovascular techniques, balloon angioplasty, and stenting have become first-line therapies for the SMA. Compared to open surgery, endovascular treatment has the advantages of involving less trauma, a faster recovery, and shorter hospital stays. ⁷ Hybrid procedures perform retrograde SMA stenting via open or laparoscopic exposure of the distal SMA with direct vessel puncture. The advantage of this is the ability to directly inspect bowel viability before and after the procedure. If percutaneous SMA stenting is not feasible, hybrid procedures act as reliable alternatives. However, hybrid procedures have been reported to entail longer operative times, and higher morbidity and result in mortality rates. ⁸

In this case, antegrade endovascular revascularization was initially attempted. However, traditional antegrade SMA stenting is not feasible for all cases of CMI. The patient had an SMA ostial occlusion without a stump, which poses a challenge for endovascular treatment. In SMA ostial occlusions, angiography often cannot define the location of the origin, resulting in inadequate guidewire and catheter support.^4,9 The patient reported herein had an SMA ostial occlusion without a visible stump. Despite angiography from multiple angles, the SMAorigin could not be identified. However, the antegrade crossing of the lesion failed despite multiple attempts. Ultimately, the retrograde crossing of the SMA lesion via the Arc of Buhler was performed, followed by antegrade angioplasty and stenting. The Arc of Buhler was used for retrograde access in this case. This rare arterial connection between the celiac trunk and SMA was first reported by Buhler in 1904. The Arc of Buhler is present in approximately 3.3% of the normal population and is hemodynamically significant in 50% of patients with this anomaly. ¹⁰ It has been described as protective against mesenteric ischemia. ¹¹ In patients with isolated celiac or SMA stenosis or occlusion, collateral flow to the mesentery is supplied predominantly by the gastroduodenal artery (GDA). ¹² In cases of either SMA or celiac ostial occlusion, the Arc of Buhler may provide a new route for endovascular access. In combined celiac and SMA stenoses, the Riolan arterial arch is the primary collateral pathway, which has a significantly increased prominence of collateral vessels seen with stenoses exceeding 70%. ¹² Retrograde SMA revascularization through the IMA-Villemin arcade has also been reported. ⁹ The Riolan arch and Villemin arcade are other options for retrograde access to treat SMA lesions.

There are some difficulties and solutions for retrograde endovascular repair. First, this retrograde route is long and tortuous, impairing the controllability of the guidewire and catheter. To address this, a 6F, 90 cm sheath was placed directly into the CT for support to advance the microcatheters and wires across the entire occlusion. Second, the Arc of Buhler is small and fragile, rendering it at risk from injury. Therefore, the tailored selection of the guidewire and catheter is critical. A combination of a 5F single curve catheter, microcatheter, and 0.014 wire was used in this case. After crossing the distal SMA via the Arc of Buhler, the soft microcatheter was advanced to avoid potential injury. Third, the guidewire snare capture from the femoral access must be performed gently to avoid transection.

This case study has some limitations. First, it only included one patient. Second, in performing retrograde reconstruction via the Arc of Buhler to treat the initial segment occlusion of the SMA, the Arc of Buhler has a small diameter, long working distance, and high demand for intravascular technology. Preoperative evaluation and the preparation of instruments are necessary to reduce complications.

Conclusion

Endovascular treatment of SMA lesions is safe and effective. The presence of the Arc of Buhler or Riolan arch can increase the success rate of the endovascular repair of SMA ostial disease.