Abdominal Angina Treatment & Management

No effective medical therapy exists. Percutaneous transluminal angioplasty (PTA) may be an alternative therapy for selected patients.

Currently, the most common indication for treatment of stenoses or occlusions of mesenteric vessels is the presence of symptoms related to intestinal ischemia. In the absence of sufficient data on the natural history of mesenteric arterial stenosis, the presence of asymptomatic disease does not constitute an indication for treatment. In the only study reporting the clinical course of patients with asymptomatic stenosis of mesenteric vessels, Thomas and colleagues reviewed 980 aortograms and identified 15 patients with stenosis of all 3 mesenteric vessels, only 4 of whom developed symptoms. ^{[6, 7]}

Mesenteric revascularization relieves the symptoms of abdominal angina and may prevent intestinal infarction. Classically, the operation for relieving the symptoms of abdominal angina includes thrombectomy (removal of the obstructing lesion) and/or bypass of the obstructed portion of the blood vessel with an endogenous or prosthetic vascular conduit. Because atherosclerosis involves systemic circulation, generally all 3 blood vessels (celiac artery, superior mesenteric artery, inferior mesenteric artery) are involved. Typically, patients become symptomatic only when all 3 blood vessels are severely narrowed by atherosclerosis. Relieving the symptoms of abdominal angina requires revascularization of at least 2 of the 3 blood vessels.

With the advent of modern endovascular surgery, many new techniques have emerged as possible alternatives to bypass surgery. Its less invasive nature makes endovascular surgery ideal for patients with multiple comorbidities, who may be at high risk for complications from open surgery.

When endovascular surgery for mesenteric revascularization is performed, the patient is placed on a fluoroscopy table and sedated by the anesthesiologist. Generally, most of these procedures do not require general anesthesia. Bilateral groins are prepped and draped in standard surgical fashion, the femoral pulse is palpated, and a needle is inserted into the artery. Using the Seldinger technique, a guide wire is inserted through the needle, and its position is checked with fluoroscopy. The artery is dilated, and sheaths are left in place. An appropriate catheter is introduced through the sheath, and an angiogram is performed.^[8] Below is a more detailed description of endovascular surgery.

Endovascular surgery

First, an aortogram is performed, and the origins of the celiac, superior mesenteric, and inferior mesenteric arteries are visualized. The left anterior oblique view is best for visualizing the origins of the celiac and superior mesenteric arteries. Once a narrowed artery is identified, a guide wire is passed through the catheters, and an attempt is made to pass the wire across the narrowed portion of the artery under direct fluoroscopy. Once the wire is passed across the stenotic area, the artery's narrowed portion can be dilated with a dilator, and a balloon angioplasty is performed.

If residual stenosis after the angioplasty is more than 50% of the expected artery luminal, it is advisable to place a stent^[9] across the narrowed portion of the blood vessel. After stent placement, an angiogram is performed to determine whether there has been a complete resolution of stenosis. If resolution has occurred, the catheters and sheaths can be removed. The arteriotomy site in the femoral arteries can be closed by various commercially available endovascular devices or by open surgical techniques. After the completion of the procedure, patients are started on a clear liquid diet, with the diet advanced as tolerated.

Potential complications of endovascular mesenteric revascularization procedures are dissection of mesenteric arteries (which necessitates conversion to open surgery), rupture of mesenteric arteries (small areas of perforation can be covered by stent grafts, but larger areas of perforation require open surgery), embolization of atherosclerotic plaques (which can lead to gangrene of the small/large bowel), groin hematoma (which necessitates performing duplex ultrasonography to rule out pseudoaneurysm of the common femoral artery), and acute limb ischemia (from embolization of atherosclerotic plaques to the extremity).

Open surgery

Lesions that are not amenable to endovascular management are dealt with through open surgical technique. The surgery is performed under general anesthesia, the patient’s abdomen is prepped and draped, and a midline incision is made from xiphoid to pubic tubercle. Skin, subcutaneous tissue, and anterior rectus fascia are divided, and the peritoneal cavity is then entered. The transverse colon is reflected upwards, and the middle colic artery is identified and traced back to the origin of the superior mesenteric artery. Proximal and distal control of the superior mesenteric artery is obtained and an arteriotomy is performed to open the artery, followed by embolectomy and removal of atherosclerotic plaques.

There are 2 types of arteriotomy that can be performed: transverse and longitudinal. Transverse arteriotomy can be closed primarily, but for longitudinal arteriotomies, a vein patch closure is preferred to avoid residual stenosis of the artery. Other surgical options include the following:

• Antegrade bypass: A vascular conduit is used to bypass the stenosed area of the mesenteric vessel. Inflow is from the supraceliac aorta. Unlike other vascular bypasses, where native vein is the preferred conduit, prosthetic grafts are more suitable for mesenteric revascularization. (See first 3 images below.)
• Retrograde bypass: In this bypass, inflow for the conduit comes from the distal, nondiseased portion of the aorta or common iliac arteries. (See fourth image below.) The celiac artery is exposed at its origin in preparation for antegrade bypass. The superior mesenteric artery and several branches are exposed for antegrade bypass. This photo shows an antegrade bypass from the aorta to the superior mesenteric artery and the celiac artery (superior mesenteric artery anastomosis is shown) using a Dacron graft. This operative photograph shows a completed retrograde bypass to the superior mesenteric artery using ePTFE graft material. Photograph courtesy of Jamal Hoballah, MD, University of Iowa College of Medicine.

Classic surgical operations have excellent outcomes. Possible complications include embolization of atherosclerotic plaques, leading to gangrenous bowel, wound infection, and damage to native aorta/iliac arteries.

• Intraoperative duplex ultrasonographic examination is performed to confirm the technical adequacy of the revascularization, as shown below. This completion duplex ultrasonographic study shows excellent flow at the distal anastomosis.
• Controversies in surgical treatment include the following:

  • Antegrade bypass versus transaortic endarterectomy versus retrograde bypass
  • The role of duplex ultrasonography in follow-up
  • The role of magnetic resonance imaging (MRI) in follow-up
  • The management of asymptomatic occlusion detected at follow-up
  • The best material for bypass, ie, vein or prosthetic graft
• The specific approach to surgical reconstruction, ie, bypass versus endarterectomy (shown below), depends on the location and number of stenoses, previous surgeries, patient comorbidities, and local operative conditions. Because patency and the rates of morbidity and mortality are similar for both types of surgery, the authors prefer to individualize each patient, applying the technique best suited to the circumstances. Follow-up of patients with duplex ultrasonography is performed yearly for the first several years. Asymptomatic occlusions are followed expectantly. Most patients succumb to other atherosclerotic comorbidities before developing symptomatic restenoses or occlusions. However, if a restenosis is identified, it is treated based on the same criteria as the original lesion. This diagram shows the possible incision for a trapdoor aortotomy. Plaque at the orifices of the visceral vessels is removed after the trapdoor incision is lifted. When a satisfactory endarterectomy has been achieved, the trapdoor is sutured shut.

• Although most of these patients are cachectic, preoperative central venous nutrition has not been shown to decrease complications and is employed only selectively.
• No particular dietary restrictions are associated with the surgery. After adequate surgical correction, patients may resume the usual diet for their particular underlying medical condition (if any).