Mesenteric Ischemia for the Acute Care Surgeon

Mesenteric ischemia remains one of the most challenging diseases for the acute care surgeon to care for. Identification of the disease process and expedient progression to therapy are the key components of successful management. Depending on etiology, ear

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Rebecca JoAnne Weddle, Justin J.J. Watson, and Jennifer Marie Watters

Mesenteric ischemia remains one of the most challenging diseases for the acute care surgeon to care for. Identification of the disease process and expedient progression to therapy are the key components of successful management. Depending on etiology, early treatment with revascularization, anticoagulation, resuscitation, antibiotics, and early surgical intervention remain paramount to improve outcomes and prevent disease progression. The mainstays of therapeutic advancement in the recent era have focused on evolution of endovascular techniques. Despite these advancements over the past 30 years, mesenteric ischemia remains a devastating disease with high mortality rates. This chapter describes a multidisciplinary approach to caring for these challenging patients, reviewing classical and novel therapeutic methodologies.

Splanchnic Vascular Anatomy and Physiology Adept diagnosis and treatment of mesenteric ischemia requires a thorough understanding of splanchnic anatomy and physiology. The splanchnic viscera is a unique vascular network, adapted for absorption and distribution of nutrients. It is important for the surgeon to note significant blood flow variations of splanchnic arteries, veins, and collateral vessels during assessment for mesenteric ischemia. Splanchnic vascular anatomy has well-documented patterns and variations. In normal anatomy, the superior mesenteric artery (SMA) originates 1–2 cm below the celiac trunk (CA) with extensive branches to the jejunum and ileum as well as the colon. The inferior mesenteric artery (IMA) arises 5–6 cm below the SMA and normally supplies the left half of the transverse colon and entire descending colon via the left colic artery. It continues with several sigmoid R.J. Weddle • J.J.J. Watson • J.M. Watters (*) Division of Trauma, Critical Care, and Acute Care Surgery, Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Rod L611, Portland, OR 97239, USA e-mail: [email protected]; [email protected]; [email protected]

branches with terminal branching to paired superior hemorrhoidal arteries. Venous anatomy parallels the arterial blood supply and partially perfuses the liver via the portal vein. The portal vein arises from the confluence of the splenic vein and superior mesenteric vein (SMV). Within the gastrointestinal vasculature, there are areas with redundancy and extensive collateralization that are important to consider in the evaluation of mesenteric ischemia. Collateral vessels occur at several different levels. These include large vessel anastomoses such as the Arc of Riolan and the marginal artery of Drummond. The Arc of Riolan, also known as Haller’s anastomosis or the meandering mesenteric artery, connects the proximal middle colic artery with the left colic artery [1]. This provides anastomoses between the SMA and IMA [1]. The marginal artery of Drummond is nearly always present, and runs near the bowel wall in the mesentery anastomosing the IMA and the SMA.