Acute and Chronic Mesenteric Ischemia

Although advances in diagnostic imaging, surgical technique, asepsis, and antibiotics have improved outcomes in most surgical diseases over the last several decades, mesenteric ischemia remains a highly morbid condition. Fortunately it remains a rare occurrence, accounting for less than 1 in every 1000 hospital admissions [1]. Likewise, mortality rates remain elevated at 30 % to 90%, depending on the etiology [2–6], and may in fact be even higher if deaths in patients who have undiagnosed mesenteric ischemia are considered. In one review, only one third of patients who had acute mesen-teric ischemia were correctly diagnosed before surgical exploration or death [5]. Another review of autopsy cases in Sweden suggested true mortality rates may exceed 90 % for mesenteric ischemia, and in only 33 % was the di-agnosis even considered before death [7]. Despite its relative infrequency, the high morbidity and mortality rates thus underscore the need for surgeons to be acutely aware of the presentation and management of this disease process. Mesenteric ischemia occurs when visceral tissues receive inadequate blood flow. This may be a consequence of an arterial embolus or thrombo-sis, venous thrombosis limiting arterial inflow, or even extrinsic compression of mesenteric vessels. Smooth muscle tone within the mesenteric vessels is heavily autoregulated, increasing splanchnic blood flow after a large meal from 10 % of cardiac output at rest to up to 35 % [8]. When demand exceeds the capacity of the mesenteric circulation because of intrinsic or extrinsic lesions, the bowel becomes ischemic, with the mucosa being most vulnerable to inadequate blood flow. The diagnosis of mesenteric ischemia is often one of exclusion, made after Surg Clin N Am 87 (2007) 1115–1134eliminating more common possibilities. Patients most often present with abdominal pain, unfortunately a vague complaint common to scores of other diagnoses. Other associated symptoms, such as nausea, vomiting, * Corresponding author