Step 1. Vascular Access and Sheath Selection

Most commonly, access for mesenteric artery intervention is gained through a common femoral artery approach. An alternate approach is through the left brachial artery; however, this is associated with a higher rate of access site complications [14]. More recently, the radial approach has been used. After puncturing the chosen vessel, a vascular sheath is placed. The size and length of the sheath will be determined by the devices intended for use as well as access site. For femoral access many operators will select a 5–7 Fr vascular sheath ranging in length from 45 to 55 cm. Angled sheaths or guiding catheters will provide additional support for therapeutic devices. Larger sheath sizes will facilitate the use of guiding catheter for increased support in a coaxial system. Tip deflecting access sheaths, guide catheter such as the Morph AccessPro, and Universal Deflectable guides (Biocardia, San Carlos, CA, USA), can be helpful in negotiating the challenging SMA angles when a femoral approach is chosen. The brachial approach, which can provide greater pushability and torquability for unfavorable SMA angles, requires a longer sheath, typically 90 cm.

Step 2. Diagnostic Angiography

A flush catheter is positioned in the abdominal aorta above the origin of the celiac artery. A lateral digital subtraction angiogram is performed to characterize the occlusion length in the SMA, the presence of a stump, calcifications, as well as to evaluate patency of the celiac artery [14] (Figure 7.1).

Step 3. Vessel Selection

While working in a lateral view, the occluded vessel or stump is probed with a diagnostic catheter and hydrophilic wire such as a 0.035‐in. Glidewire (Terumo, Elkton, MD, USA). Some diagnostic catheter choices include a C1, Simmons I, or Sos Omni Selective catheters (Angiodynamics, Latham, NY, USA). If a 0.035 wire cannot be advanced through a CTO, a guiding catheter can be introduced over the wire to provide additional support. If a 0.035 wire still cannot be advanced through the lesion, a 0.018 or a 0.014 wire can be used with an appropriately matched microcatheter (Figures 7.2 and 7.3).

Step 4. Selective Angiography

A catheter is advanced over the wire and through the lesion. A hydrophilic glide catheter (Terumo, Elkton, MD, USA) may be needed if the catheter cannot be easily advanced through the diseased vessel. Selective angiography of the SMA is performed through a diagnostic catheter or microcatheter to ensure the catheter tip is in the true lumen of the vessel and a dissection or perforation has not occurred. The angiogram will also determine the landing site of a stent. Intravascular pressure measurements can be made at this point. A gradient greater than 10 mmHg is considered significant.

Step 5. Placement of a Working Wire

A nonhydrophilic working wire is replaced in the SMA through the catheter. The wire should be positioned distal enough to have good purchase within the vessel, but not too distal in a branch vessel where it could cause a perforation. The catheter is exchanged over the wire for a stent or angioplasty balloon. Embolic prevention has been observed in selected patients when using an embolic protection device [15]. These devices are used as a working wire while having an embolic protection apparatus such as a filter or balloon occlusion at the distal end of the wire. If a 0.035 device is chosen for intervention, the second wire like a V‐18 or V‐14 ControlWire (Boston Scientific, Marlborough, MA, USA) can be used as a buddy wire for additional support. The vascular sheath or guiding catheter should be as close to the ostium of the vessel as possible to support passage of a balloon or stent.

Step 6. Stent Placement

A balloon‐expandable stent is advanced over the wire and positioned in the proximal vessel. Before final positioning and deployment, an angiogram can be performed through the side arm of the sheath so that the proximal landing of the stent can be visualized. The proximal end of the stent should be deployed 3–5 mm extending into the aorta to ensure all proximal/ostial disease is covered. Balloon‐expandable stents are preferred over self‐expanding stents due to the precise placement. Stent selection will be based on the target vessel size and length of disease. Typical stent dimensions range from 5 to 7 mm × 15 to 40 mm. An additional stent may be deployed if the initial stent does not fully cover the target lesion. A self‐expanding stent can be used in more distal lesions or if an extension is required. Predilation using an angioplasty balloon may be needed if the stent cannot be advanced over the wire and through the lesion. Predilation can also be used if the vessel is completely occluded or the lesion is judged to be high grade. Predilation may increase the risk of distal thromboembolization (Figure 7.4).

Step 7. Posttreatment Angiography

A posttreatment angiogram is performed from the aorta. Residual stenosis of less than 30% is considered technically successful [14]. Intravascular pressure measurements can also be acquired with a gradient of less than 10 mmHg desired. Carefully evaluate the angiogram for evidence of distal embolization. Comparison with the prestent/angioplasty angiogram is essential (Figure 7.5).

Step 8. Revision

Poststent placement angioplasty or additional stenting may be necessary if the angiographic result is not adequate or if the pressure gradient is higher than 10 mmHg.

If present and recognized, distal embolization may require aspiration using an appropriately sized thrombectomy catheter. If the emboli cannot be aspirated, the patient is treated with anticoagulation. If signs of bowel infarction develop, emergent surgery with bowel resection is warranted.