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Bhatt DL, editor. Guide to Peripheral and Cerebrovascular Intervention. London: Remedica; 2004.

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Guide to Peripheral and Cerebrovascular Intervention.

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Mesenteric artery stenosis

and .

Chronic mesenteric ischemia is usually related to progressive atherosclerotic narrowing of the mesenteric arteries. Due to the wide range of causes, mesenteric ischemia often goes undiagnosed and untreated, leading to high morbidity and mortality.

Mesenteric arterial anatomy

An understanding of mesenteric arterial anatomy is crucial to understanding and managing these patients. The gastrointestinal tract is supplied by the celiac trunk, the superior mesenteric artery (SMA), and the inferior mesenteric artery (IMA) [13]. The celiac trunk originates from the anterior aorta just below the diaphragm at the level of the thoracic vertebrae 12 (T12) or the first lumbar vertebra. It branches into the common hepatic, splenic, and left gastric arteries.

  • The left gastric artery supplies the lesser curvature of the stomach and collateralizes with the right gastric artery branch of the hepatic artery.
  • Brances of the common hepatic artery include the hepatic and gastroduodenal arteries; the latter supplies the distal stomach and duodenum.
  • The gastroduodenal artery supplies the greater curvature of the stomach via the right gastroepiploic artery.

The SMA is located a few centimeters below the celiac artery, usually around the first lumbar vertebra at 20°–30° caudal angulation. It supplies the pancreas, duodenum, jejunum, and the right half of the colon. The branches of the SMA are the inferior pancreaticoduodenal artery, the jejunal and ileal braches, the ileocolic artery, the right colic artery, and the middle colic artery.

The IMA originates from the mid to distal infrarenal aorta around the third lumbar vertebra, which is usually ≥ 5 cm below the origin of the SMA. It supplies the distal transverse, left, and sigmoid portions of the colon and the rectum. Its branches are the left colic artery, the sigmoid (inferior left colic) arteries, and the superior rectal artery. The SMA and IMA collateralize via the marginal artery of Drummond and the meandering mesenteric artery.

Arcuate ligament syndrome

Arcuate ligament syndrome is caused by compression of the celiac trunk by the median arcuate ligament of the diaphragm and is typically seen in middle-aged, female patients. Individuals complain of abdominal pain with eating, postprandial emesis, and may present with marked weight loss. The pain is usually less severe than intestinal ischemic pain. Bruit may be heard in the upper abdomen during a physical exam. On angiography with the image intensifier in the lateral position, the median arcuate ligament is seen to compress the celiac axis; this is accentuated by deep expiration (see Figure 5). The historical treatment is surgical division of the median arcuate ligament. This is curative, although surgical bypass is sometimes necessary.

Figure 5. A celiac artery with (a) minimal narrowing, (b) accentuated to a moderate degree by deep expiration.

Figure 5

A celiac artery with (a) minimal narrowing, (b) accentuated to a moderate degree by deep expiration. (Figure courtesy of Deepak L Bhatt, MD.)

Clinical features

Mesenteric artery stenosis results in insufficient blood flow to the small intestine, causing intestinal ischemia. Chronic mesenteric ischemia is usually due to atherosclerosis, but is rarely caused by extensive fibromuscular disease or trauma. The celiac trunk, SMA, and IMA usually have ostial disease and occlusions are typically found in the proximal few centimeters of these arteries. Chronic mesenteric ischemia results when at least two of the three major splanchnic arteries have severe stenosis. The SMA is almost always involved in symptomatic cases. At rest, patients have sufficient intestinal blood flow to maintain gut viability and prevent symptom development. However, the increased demand on mesenteric circulation after a meal may overwhelm the compensatory ability of the collateral circulation, thereby causing postprandial intestinal angina.

Patients with chronic mesenteric ischemia typically present in the fifth or sixth decades of life [14,15]. They often have atherosclerotic disease elsewhere, such as peripheral vascular disease, coronary artery disease, and/or cerebrovascular disease. Females are more likely to be affected than males. Most patients complain of postprandial abdominal pain. The classic description is crampy or colicky pain located in the epigastric area that begins 15–30 minutes following eating, lasts for 2–3 hours, and gradually subsides. The postprandial pain can result in fear of food (sitophobia) [16]. Patients may compensate by eating smaller portions. Most patients with chronic mesenteric ischemia have marked weight loss. A physical examination often reveals weight loss and generalized signs of atherosclerosis. Rarely, patients have an abdominal bruit. Most often, patients initially receive a malignancy work-up.

Diagnosis

Plain abdominal x-ray, CT, and endoscopy are insensitive in diagnosing chronic mesenteric ischemia, but can rule out other diseases (such as malignancy). Duplex ultrasound requires excellent technical skills and a well-prepared patient. Vessel tortuosity, respiratory motion, and the presence of bowel gas impede good visualization.

Velocity parameters used to determine the presence of ≥ 70% stenosis (peak systolic velocity >275 cm/s for the celiac artery and >200 cm/s for the SMA) have been reported with sensitivities and specificities of around 90% compared with angiography. Therefore, duplex ultrasound is fairly reliable in excluding the diagnosis of chronic mesenteric ischemia.

Gadolinium-enhanced MRA has also been used in the diagnosis of mesenteric artery stenosis. Biplanar aortography, including selective engagement of the celiac trunk, SMA, and IMA, remains the diagnostic test of choice. Lateral abdominal aortograms are optimal to visualize the origin and the proximal portion of the mesenteric arteries. In addition to defining the extent of the disease, angiography determines collateral flow. Chronic mesenteric ischemia requires flow-limiting stenosis or occlusion of at least two of the three mesenteric arteries. In general, large collaterals (such as the wandering artery of Drummond from the IMA to the SMA in the case of SMA stenosis) are present and help to confirm the presence of lesions that are suspected to be flow limiting.

Management

Patients with chronic mesenteric ischemia have traditionally been treated with mesenteric vascular surgical revascularization [17,18]. Overall, the operative mortality remains high (approximately 7.5%–10%) [16]. There are several surgical revascularization strategies, including visceral endarterectomy, antegrade supraceliac aorta to visceral bypass, and retrograde infrarenal aorta to visceral bypass. Before surgical revascularization, the patient may benefit from total parenteral nutrition (TPN). Although there is controversy regarding the length and benefit of TPN, improving the nutritional status of the patient prior to surgery seems rational.

Transaortic visceral endarterectomy is a technically challenging procedure that requires extensive retroperitoneal vascular exposure. This technique also has a greater risk of paraplegia because of supraceliac aortic cross-clamping. Endarterectomy may be particularly beneficial in cases where the patient has both visceral stenosis and RAS. Endarterectomy is very difficult in patients with extensive aortic atherosclerosis and an alternative technique may be considered.

Retrograde SMA bypass is the most commonly performed visceral bypass procedure. The simplicity of the approach to the infrarenal aorta and infrapancreatic SMA makes this procedure attractive to surgeons. With retrograde bypass, care must be taken to configure a graft that will not kink. Antegrade bypass is the procedure of choice when there is marked infrarenal aortic atherosclerosis. Endarterectomy appears to have the lowest recurrence rate, followed by antegrade bypass reconstruction, and finally retrograde reconstruction.

Endovascular treatment is becoming the first-line therapy for chronic mesenteric ischemia at many experienced centers. Early studies found high restenosis rates; however, stenting has significantly improved outcomes. Visceral surgical revascularization in a malnourished patient, even in specialized centers, leads to significant morbidity and mortality in comparison with endovascular treatment. The endovascular approach is less invasive and compares favorably with surgery in terms of clinical success, complications, and long-term outcomes. Steimetz et al. demonstrated that endovascular therapy for mesenteric artery stenosis is efficient in both the short and long-term [19].

Angiography

Typical indications for mesenteric angiography include chronic mesenteric ischemia or intestinal angina, acute mesenteric ischemia, and uncontrolled gastrointestinal bleeding. Initially, lateral aortography should be performed to identify the origin of the mesenteric vessels (see Figure 6). Selective cannulations of the celiac trunk (see Figure 7), SMA (see Figure 8), and IMA can usually be performed using a JR4 or LIMA catheter in the lateral projection. In some cases, catheters with longer tips, such as the SOS or Cobra catheters, may be needed for selective injections.

Figure 6. (Above left) A lateral abdominal aortogram to visualize the mesenteric arteries.

Figure 6

(Above left) A lateral abdominal aortogram to visualize the mesenteric arteries. Lateral aortograms are optimal to visualize the origin and proximal portion of the mesenteric arteries. SMA: superior mesenteric artery.

Figure 7. (Above right) Selective cannulation of the celiac trunk with a Judkin's Right 4 catheter.

Figure 7

(Above right) Selective cannulation of the celiac trunk with a Judkin's Right 4 catheter. The angiogram shows a normal celiac trunk bifurcating into the common hepatic and splenic arteries in the anteroposterior view.

Figure 8. (Left) Selective cannulation of the superior mesenteric artery (SMA) with an SOS catheter.

Figure 8

(Left) Selective cannulation of the superior mesenteric artery (SMA) with an SOS catheter. The angiogram shows an SMA of normal appearance

For good quality mesenteric angiograms without streaming, the rate of injection should match the flow rate of the vessel being studied. Typical flow rates are 10 mL/s for the celiac trunk, 8 mL/s for the SMA, and 3 mL/s for the IMA. DSA acquisition may be less helpful for mesenteric angiography due to the presence of bowel gas. In patients being evaluated for gastrointestinal bleeding, the clinically suspected vessel should be injected first.

Intervention

Mesenteric artery revascularization can be performed using either the femoral or the brachial approach, with the femoral approach being preferred. Many of the concepts discussed in the section on renal artery intervention also apply to mesenteric artery revascularization, including the use of similar guide catheters, such as the Hockey Stick, Multipurpose, JR4, and RDC catheters in 6–8 Fr sizes. Most operators currently use a 6-inch Fr guide catheter and a 0.014-inch guidewire system.

Once an appropriate guide is seated in the ostium, unfractionated heparin is administered at 60 U/kg to achieve an activated clotting time of 200–250 seconds. The stenosis is crossed with a 0.014-inch guidewire and predilated with an appropriately sized balloon catheter (5–6 mm diameter for most mesenteric arteries). Mesenteric angioplasty has a good technical success rate but a high rate of restenosis [20], and routine stenting is recommended. Following dilatation, an appropriately sized stent (typically 6–7 mm diameter) is advanced and deployed to cover the entire lesion, with 1–2 mm of the stent extending into the aorta to ensure complete coverage of the ostium (see Figure 9).

Figure 9. Successful endovascular stenting of superior mesenteric artery stenosis for chronic mesenteric ischemia.

Figure 9

Successful endovascular stenting of superior mesenteric artery stenosis for chronic mesenteric ischemia. (a) Pre-stenting; (b) Post-stenting. (Figure courtesy of Deepak L Bhatt, MD.)

A major consideration in the choice of the stent is that it has good radial strength to prevent recoil of the ostium for mesenteric artery stenting. The ostium is typically then postdilated with the stent balloon partially in the aorta at higher atmospheres to flare the ostium. Similarly to in renal stenting, care should be taken to align the balloon catheter coaxially during postdilatation to avoid creating aortic dissections. Potential complications of mesenteric artery stenting include atheroembolization, aortic dissections, and access site vascular complications. Postprocedure, patients should receive lifelong aspirin and clopidogrel for 1–12 months. In the future, emboli protection devices and drug-eluting stents may further improve the safety and durability of endovascular mesenteric artery revascularization.

By agreement with the publisher, this book is accessible by the search feature, but cannot be browsed.

Copyright © 2004, Remedica.
Bookshelf ID: NBK27423

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