Aortic intramural hematoma: Current diagnostic and therapeutic recommendations

Opinion statement Aortic intramural hematoma (IMH) is an acute, potentially lethal disorder that is similar to but pathologically distinct from acute aortic dissection. Although hemorrhage into the aortic media occurs in both disorders, an intimal tear with resultant false lumen is not present in IMH. Instead, hemorrhage occurs within the aortic wall either due to rupture of the vasa vasorum or, less commonly, because of an atherosclerotic penetrating aortic ulcer. The most common risk factors associated with IMH are hypertension, atherosclerosis, and advanced age. IMH is life-threatening because the hematoma may extend along or rupture through the aorta, leading to hemothorax, cardiac tamponade, stroke, mesenteric ischemia, or renal insufficiency. Optimal treatment is still somewhat controversial; however, there is no question that hypertension must be treated effectively and immediately. This is usually best accomplished by intravenous infusion of β-blocking agents, with or without the addition of sodium nitroprusside. Recent studies support surgical treatment (ie, aortic root replacement) for IMH involving the ascending aorta, although some subsets of this population may be at lower risk and may benefit from medical therapy alone. In patients with IMH involving only the descending aorta, medical therapy alone is recommended (unless impending rupture, aortic aneurysm, or end-organ ischemia occurs). Patients who survive the acute event require intensive treatment of hypertension and frequent follow-up examinations. Because this population (especially the subset with penetrating aortic ulceration) is at high risk for aortic aneurysm and rupture, serial imaging studies of the aorta are essential.