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CHAPTER 88 • Renal Revascularization 961

Right renal vein

retracted cephalad

Dividing

right renal artery

Saphenous vein graft

Proximal anastomosis

Completing distal

anastomosis

Saphenous vein graft

Completed hepatorenal

bypass

FIGURE 88 –6, cont’d

962 Section XII • Vascular

3. CLOSING

◆ Both of the inner two layers of the right and left subcostal incisions are closed in a similar

fashion with running absorbable suture (2-0 Vicryl), and the outer layers (external oblique

and anterior rectus fascia) are closed with running monoﬁ lament (2-0 PDS or Maxon)

suture.

STEP 4: POSTOPERATIVE CARE

◆ The patient is returned to the ICU with arterial line and Swan-Ganz pulmonary artery

catheter in place. IV ﬂ uids are administered to control ﬂ uid volume and blood pressure.

Nicardipine or sodium nitroprusside is used to control blood pressure. Beta blockade begun

in the preoperative period is continued to control heart rate and blood pressure. Urine out-

put is carefully monitored, and IV ﬂ uid administration is adjusted accordingly.

◆ There are often signiﬁ cant ﬂ uid shifts in the immediate postoperative period. A combina-

tion of ﬂ uid administration, vasopressors, and antihypertensive medications may be

required to ensure adequate perfusion pressures and to prevent hypertensive crises.

STEP 5: PEARLS AND PITFALLS

◆ The renal artery should be carefully palpated to determine the distal extent of the plaque

before an aortorenal bypass or endarterectomy is performed. This maneuver is especially

important if endarterectomy is contemplated if difﬁ culties with the end point are to be

avoided.

◆ Each renal anastomosis should be completed in 15 to 20 minutes. If prolonged renal ische-

mic times are anticipated, cold electrolyte solution can be infused into the renal artery and

the kidney packed in ice.

◆ Immediate evaluation of the patency of the repair with duplex ultrasound or renal isotope

ﬂ ow studies is indicated if anuria develops in the postoperative period. Prompt return to

the operating room is indicated if the vessels are occluded.

◆ Atheroembolism is an uncommon but serious complication of renal revascularization. Care-

ful preoperative assessment of the aorta to determine the presence and location of athero-

matous debris or thrombus on a CT scan and the correct sequential application and

removal of clamps is imperative if this complication is to be avoided. Oliguria or anuria that

does not resolve, eosinophilia, and cholesterol crystalluria are clues to the diagnosis.

◆ In patients with oliguric acute renal failure dialysis, enteral or parenteral nutrition should

be undertaken early to avoid the rapid loss of muscle mass encountered in these patients.

CHAPTER 88 • Renal Revascularization 963

SELECTED REFERENCES

1. Hansen KJ, Tribble RW, Reavis SW, et al: Renal duplex sonography: Evaluation of clinical utility.

J Vasc Surg 1990;12:227-236.

2. Wylie EJ, Perloff DL, Stoney RJ: Autogenous tissue revascularization techniques in surgery for renovascu-

lar hypertension. Ann Surg 1969;170:416-428.

3. Moncure AC, Brewster DC, Darling RC, et al: Use of the splenic and hepatic arteries for renal revascular-

ization. J Vasc Surg 1986;3:196-203.

4. Benjamin ME, Dean RH: Techniques in renal artery reconstruction: Part I. Ann Vasc Surg 1996;10:

306-314.

5. Benjamin ME, Dean RH: Techniques in renal artery reconstruction: Part II. Ann Vasc Surg 1996;10:

409-414.

964

INTRODUCTION

◆ Despite recent advances in the diagnosis and treatment of mesenteric ischemia, the mortal-

ity rate remains between 59% and 93%. The low incidence of mesenteric ischemia, as well

as the difﬁ culties and delays encountered in establishing the diagnosis, contributes to

the high morbidity and mortality rates. Acute mesenteric ischemia may either be caused

by thromboembolic occlusive disease (80%) or result from nonocclusive ischemia (20%).

The thromboembolic causes of mesenteric ischemia include mesenteric embolism (50%),

thrombosis of a pre-existing atherosclerotic oriﬁ cial stenosis (20%), and mesenteric venous

thrombosis (10%). Nonocclusive mesenteric ischemia occurs in the absence of anatomic

arterial or venous obstruction and is the result of hypoperfusion-induced vasoconstriction

throughout the entire mesenteric circulation. Chronic mesenteric ischemia is due to athero-

sclerotic occlusive disease in most patients. Less common causes include aortic coarctation,

aortic dissection, mid-aortic stenosis, vasculitides, ﬁ bromuscular dysplasia, neuroﬁ bro-

matosis, and celiac artery compression syndrome.

STEP 1: SURGICAL ANATOMY

◆ The blood supply to the abdominal viscera arises from the celiac, superior mesenteric, infe-

rior mesenteric, and hypogastric arteries. The celiac artery arises from the aorta at the level

of the T12 and L1 vertebral bodies and is 1.5 to 2.0 cm in length. The artery divides into

the left gastric, splenic, and common hepatic arteries. At its origin, the artery is surrounded

by the ganglia and ﬁ bers of the celiac autonomic nerve plexus.

◆ The superior mesenteric artery (SMA) arises 1 cm below the celiac trunk at the L1-L2 inter-

vertebral disc. It lies posterior to the splenic vein and pancreas and is separated from the

aorta by the left renal vein.

◆ The inferior mesenteric artery (IMA), the smaller of the three vessels, arises from the ante-

rior lateral aspect of the aorta at the level of the third lumbar vertebra, approximately 3 to

4 cm above the aortic bifurcation.

◆ The abdominal viscera have a rich collateral blood supply formed by the interconnections

between the three major vessels: the celiac artery and SMA communicate via the superior

and inferior pancreaticoduodenal arteries and the SMA and IMA communicate via the arc of

CHAPTER

Mesenteric Ischemia

Glenn C. Hunter

CHAPTER 89 • Mesenteric Ischemia 965

Riolan (middle and left colic arteries). The marginal artery of Drummond formed by anasto-

moses between the main trunks and the arcades arising from the ileocolic, right colic, mid-

dle colic, left colic, and sigmoid arteries, augmented by the superior, middle, and inferior

rectal arteries—branches of the hypogastric arteries.

STEP 2: PREOPERATIVE CONSIDERATIONS

EVALUATION

◆ The modes of presentation of patients with acute mesenteric ischemia are quite varied. The

acute onset of severe abdominal pain, nausea, and vomiting in a patient with cardiac

arrhythmias suggests mesenteric embolism. The exacerbation of symptoms in a patient with

the symptom triad of abdominal pain, fear of eating, and severe weight loss is suggestive of

thrombotic occlusion of a high-grade celiac artery or SMA stenosis. The symptom complex

of diffuse abdominal pain, hypotension, and severe lactic acidosis in the setting of cardio-

genic, septicemic, or hypovolemic shock is suggestive of nonocclusive mesenteric ischemia.

The clinical presentation of mesenteric venous thrombosis is often more insidious and the

physical ﬁ ndings more subtle than those of acute arterial ischemia. However, severe abdom-

inal pain out of proportion to the physical ﬁ ndings is present in more than 80% of patients.

◆ A history of pre-existing congestive heart failure, use of digoxin or ␣-adrenergic agents,

cardiac arrhythmias, valvular heart disease, recent myocardial infarction, cardiopulmonary

bypass, hypercoagulable states, vasculitides, and malignancy should be elicited.

◆ In patients with chronic mesenteric ischemia, severe abdominal pain, fear of food, and

weight loss in patients with atherosclerotic peripheral vascular disease (PVD) or underlying

thrombotic or coagulation disorders should be elicited.

PHYSICAL EXAMINATION

◆ Careful assessment of the abdomen for the presence of distention, tenderness, signs of peri-

toneal irritation, bruits, and presence or absence of femoral pulses should be undertaken.

◆ In the early phases, signs of peritoneal irritation such as guarding and rebound tenderness

are usually absent. As the bowel becomes more ischemic, abdominal distention, absent

bowel sounds, excruciating tenderness, feculent vomiting, and occult bleeding become

evident.

DIAGNOSTIC TESTS

◆ An electrocardiogram should be performed in all patients and an echocardiogram in

selected patients with poor cardiac output. A complete blood count and routine laboratory

chemistries for electrolytes, blood urea nitrogen, creatinine, troponin levels, liver function

tests, and arterial blood gases should be performed. In patients with suspected

966 Section XII • Vascular

hypercoagulable states, blood should be drawn for the prothrombotic work-up before the

administration of heparin. Blood and blood products are typed and crossmatched.

◆ In patients suspected of having acute mesenteric ischemia, a plain abdominal radiograph

may demonstrate “thumbprinting,” ileus, or pneumatosis. A contrast-enhanced computed

tomography (CT) scan with CT angiography provides the deﬁ nitive diagnosis but does not

allow treatment with intra-arterial vasodilators.

◆ Angiography with anterior posterior and lateral views of the aorta is indicated in patients

with acute and chronic mesenteric ischemia and in whom diagnostic uncertainty exists. If

nonocclusive mesenteric ischemia is present, the angiographic catheter is left in place for

the infusion of vasodilators, such as papaverine, nitroglycerin, tolazoline, or verapamil. In

patients with exacerbation or recent onset of symptoms (less than 3 hours) found to have a

high-grade celiac artery or SMA stenosis, angioplasty and stenting should be considered.

◆ Resuscitation with intravenous ﬂ uid is begun while the investigation is ongoing. Broad-

spectrum antibiotics are administered, and any potential underlying mechanism such as

arrhythmias or congestive heart failure is corrected. A heparin infusion is begun to prevent

extension of thrombus into the microvessels.

STEP 3: OPERATIVE STEPS

1. INCISION

◆ The abdomen is opened via an upper midline incision, and the extent of the ischemia is

assessed (Figure 89-1). Perfusion of the proximal 10 to 15 cm of jejunum is indicative of

embolic occlusion, whereas bowel ischemia including this segment suggests arterial throm-

bosis. Both the small and large bowel appears dusky if nonocclusive mesenteric ischemia is

present. Segmental ischemic changes with edema of the adjacent mesentery are indicative of

mesenteric venous thrombosis. If the entire bowel is necrotic, the abdomen should be

closed and comfort measures instituted.

CHAPTER 89 • Mesenteric Ischemia 967

Midline incision

FIGURE 89 –1

968 Section XII • Vascular

2. DISSECTION

Mesenteric Embolism

◆ The transverse colon is elevated superiorly, and the fourth part of the duodenum is mobi-

lized. The small bowel is retracted to the right, and a self-retaining retractor is placed. The

SMA is isolated at the root of the mesentery and mobilized, taking care to preserve all its

branches (Figure 89-2).

Middle colic

artery

Embolus

Superior

mesenteric

artery

Jejunum

FIGURE 89 –2

CHAPTER 89 • Mesenteric Ischemia 969

Embolus

Catheter removing

embolus from proximal

superior mesenteric artery

Transverse arteriotomy

in superior mesenteric

artery

Catheter removing embolus from

distal superior mesenteric artery

FIGURE 89 –3

◆ An ACT is drawn and additional heparin is administered to ensure adequate heparinization

(ACT >250). The SMA and its jejunal branches are occluded, and a transverse arteriotomy

is made (Figure 89-3, A).

◆ A balloon catheter is then passed proximally toward the origin of the SMA, the embolus is

extracted, and the proximal SMA is occluded once adequate inﬂ ow has been restored

(Figure 89-3, B). The balloon catheter is also passed distally to ensure no thrombotic mate-

rial remains (Figure 89-3, C). The clamps are temporarily removed, and the vessel is

ﬂ ushed proximally and distally.

970 Section XII • Vascular

◆ The lumen of the SMA is irrigated with heparinized saline, and the arteriotomy is approxi-

mated with interrupted 6-0 polypropylene suture (Figure 89-3, D).

◆ The bowel is inspected, and mesenteric vessels are interrogated with Doppler ultrasound to

ensure adequate perfusion. Nonviable segments of bowel should be resected.

Interrupted

sutures to

close arteriotomy

FIGURE 89 –3, cont’d