**5.2 Surgical treatment**

Laparotomy with visceral revascularization can be used to treat patients with both AMI and CMI. Patients presenting with signs and symptoms of AMI require urgent abdominal exploration, assessment of bowel viability, and revascularization. Several techniques for the restoration of intestinal perfusion are available to the vascular surgeon, and familiarity with a variety of options is crucial. Before revascularization, large segments of both small and large intestine may appear dusky, ischemic, or necrotic.

#### **5.3 Acute mesenteric ischemia**

#### **5.3.1 SMA embolectomy**

Perfusion of the mesenteric arteries is assessed by palpation and Doppler evaluation. In cases in which the obstruction is caused by an embolus, a proximal SMA pulse is often

Mesenteric Vascular Disease 241

bilateral subcostal incision, depending on the patient's body habitus and costal cartilage flare. Supraceliac-origin grafts are a poor choice in patients with compromised cardiac or pulmonary function or those with extensive atherosclerosis or circumferential calcification of the supraceliac aorta. In these cases, infrarenal sources of inflow are preferred (18, 19, 21).

Fig. 5. Antegrade aortoceliac–superior mesenteric artery bypass

**6. Treatment of nonocclusive mesenteric ischemia** 

The infrarenal aorta, a prior infrarenal aortic graft, or the iliac artery are excellent inflow sources, Two-vessel reconstructions can be performed with retrograde grafts by doing a side-to-side anastomosis to the SMA and an end-to-side anastomosis to the common hepatic artery. These grafts may be passed on top of or beneath the pancreas and curved in a C

The primary treatment for NOMI is medical, with extensive critical care support and prompt arteriography. Operative exploration is reserved for signs of peritonitis that suggest the presence of gangrenous bowel that requires excision. Interventional therapies can be initiated at the time of the diagnostic arteriogram and are targeted at relieving vasospasm using intra-arterial infusions of vasodilator medications. The most common intra-arterial agent is phosphodiesterase inhibitor papaverine and prostaglandin (22). Surgical exploration is required for all patients who have evidence of any threatened bowel, regardless of the underlying cause. The prognosis is poor, despite the absence of organic

**5.6 Retrograde mesenteric bypass** 

shape toward the hepatic artery.

obstruction in the principal arteries.

appreciated. Systemic heparinization is established. If the artery feels relatively soft and free of atherosclerotic disease, a transverse arteriotomy is performed distal to the area of obstruction, and the arterial lumen is assessed for thrombus. Balloon-tipped embolectomy catheters are gently passed proximally and distally until no more clot can be removed. Care must be taken not to overinflate the balloons and dissect the arterial intima. Distally, mesenteric vessels are very thin, and overinflation can result in rupture and intramesenteric extravasation. The transverse arteriotomy is then closed primarily with simple interrupted Prolene sutures if no endarterectomy is necessary. In cases in which a flow-limiting plaque is present, the arteriotomy is converted to a longitudinal one, and a local thromboendarterectomy is performed. Patch angioplasty with autogenous vein is the preferred method of revascularization owing to potential contamination from concomitant bowel resection. The arteriotomy site can also be used for distal anastomosis of an antegrade or retrograde bypass if necessary.
