MEDizzy - Two days after admission to the hospital for a myocardial

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Peripheral Vascular Problems

Two days after admission to the hospital for a myocardial infarction, a 65-year-old man complains of severe, unremitting midabdominal pain. His cardiac index is 1.6. Physical examination is remarkable for an absence of peritoneal irritation or distention despite the patient’s persistent complaint of severe pain. Serum lactate is 9 mmol/L (normal is < 3 mmol/L). Which of the following is the most appropriate next step in this patient’s management?

ExplanationB. Abdominal pain out of proportion to findings on physical examination is characteristic of intestinal ischemia. The etiology of ischemia may be embolic or thrombotic occlusion of the mesenteric vessels or nonocclusive ischemia due to a low cardiac index or mesenteric vasospasm. Differentiation among these etiologies is best made by mesenteric angiography. While not without serious risks, angiography also offers the possibility of direct infusion of vasodilators into the mesenteric vasculature in the setting of nonocclusive ischemia. This patient, with a recent myocardial infarction and a low cardiac index, is at risk for embolism of clot from a left ventricle mural thrombus as well as low-flow mesenteric ischemia. If embolism or thrombosis is found angiographically (usually involving the superior mesenteric artery), thrombolytic therapy can be attempted in the absence of suspicion of ischemic bowel. Otherwise, operative embolectomy or vascular bypass is indicated to restore flow. If occlusive disease cannot be demonstrated, efforts should be made to simultaneously increase cardiac output with inotropic agents and dilate the mesenteric vascular bed by angiographic instillation of papaverine, nitrates, or calcium-channel blockers. Computed tomography is not helpful in delineating the cause of intestinal ischemia because it does not provide a sufficiently detailed image of the mesenteric vessels. Laparoscopy and/or laparotomy would be useful if ischemic bowel were suspected, although laparoscopy would not allow for adequate assessment of the visceral vessels. Flexible sigmoidoscopy, while useful in patients with ischemic colitis, has no role in the workup of mesenteric ischemia, which involves primarily the small intestine and right colon. Serum lactate is helpful in raising the suspicion of intestinal ischemia, but no absolute level should be used to decide whether or not to explore a patient.