47: CHRONIC MESENTERIC ISCHEMIA

PATIENT STORY

A 66-year-old woman with long-standing tobacco use presented with recurrent postprandial abdominal pain and food aversion for the last 18 months. An associated weight loss of 22 lb in addition to intermittent nausea, vomiting, and diarrhea was described as well. Physical examination was remarkable for a malnourished-appearing female with right carotid, epigastric, and bilateral femoral bruits. The femoral through pedal pulses were weak but palpable. Mesenteric duplex arterial ultrasonography identified 70% to 99% stenosis within the celiac and superior mesenteric arteries with abundant diffuse aortomesenteric plaque. A computed tomographic angiogram (CTA) of the abdomen confirmed the above findings and documented a meandering mesenteric artery of Moskowitz. A diagnosis of chronic mesenteric ischemia (CMI) was made.

EPIDEMIOLOGY

• Overall incidence is quite low, patients between 40 and 70 years of age, common in women.¹

• Etiology is atherosclerosis, usually affecting mesenteric arteries at the ostia or "spill-over" disease from the abdominal aorta.

• Most patients are smokers and hypertensive.

PATHOPHYSIOLOGY

• Celiac artery (CA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) usually have good pre-existent collaterals; therefore, usually two of three arteries must be critically stenosed or occluded before symptoms arise.

• Single arterial disease may become symptomatic if there is no good collateral circulation.

• CMI can lead to intestinal malabsorption, inanition, bowel infarction, and ultimately death.

CLINICAL PRESENTATION

Symptoms

• Classic triad of abdominal pain, food fear, and weight loss.

• Almost all patients develop central abdominal pain, the onset of which is usually 30 minutes postprandial, lasting minutes to hours. Patients learn to associate pain with food and hence develop food fear. Poor dietary intake leads to malnutrition and weight loss.

• Ischemic ulcerations in the stomach, duodenum, or colon may cause epigastric pain, nausea, emesis, gastrointestinal bleeding, or change in bowel habits resultant of colonic strictures.

Signs

• Patients are generally thin, underweight, with a scaphoid abdomen. Muscle wasting is seen in advanced cases.

• However, not all patients appear emaciated as CMI can affect morbidly obese patients where a 20- to 30-lb weight loss is not readily noticeable.

• Abdominal bruit and tenderness may be present, but peritoneal signs are typically absent.

• Two-thirds of patients have evidence of atherosclerosis in other vascular beds (cerebrovascular, coronary, renal, and lower extremities) such as carotid bruits, coronary artery bypass or stents, and absent pedal pulses.²

DIAGNOSIS

Laboratory Testing

• Nonspecific

Imaging Studies

Duplex Ultrasound Scan

• Elevated peak systolic velocities (PSVs) of greater than 200 cm/s in the CA and greater than 275 cm/s in the SMA are indicative of greater than 70% stenosis (Figures 47-1 and 47-2).³ Elevated end diastolic velocities ...