Effects of Hypovolemia on Aortic Dimensions

A ruptured thoracic aorta is a rare but lifethreatening condition requiring immediate intervention. Possible causes of a ruptured thoracic aorta are ruptured descending thoracic aneurysms, acute type B aortic dissections, penetrating aortic ulcers, and traumatic thoracic aortic injuries (TTAI). Thoracic endovascular aortic repair (TEVAR) offers an effective treatment for these acute thoracic aortic pathologies, and the endovascular approach appears to reduce the morbidity and mortality rates compared with traditional open surgery.1-9 At many institutions, TEVAR has become the preferred treatment for acute thoracic aortic disease.2,5,9,10 However, endovascular repair of these acute aortic pathologies is still associated with the occurrence of endoleak in 5% to 30% of cases.2,3,6,8,9,11 The majority of these endoleaks are proximal type I endoleaks, and urgent reintervention is often needed.3,11 Adequate endograft sizing using preoperative computed tomography angiography (CTA) is thought to be important in minimizing risks of endoleak and other endograft-related complications and for improving longterm outcomes after endovascular repair. Patients with thoracic aortic rupture are often admitted with considerable blood loss or hypovolemic shock. Although peripheral vasoconstriction is a well-known response to hypovolemic shock to maintain perfusion of the heart and brain,12-14 the effects of hypovolemia on the aortic dimensions remain unclear. Temporary changes in the aortic diameter during blood loss could lead to incorrect aortic measurements on preoperative CTA, inadequate endograft sizing, and increased risks of endograft-related complications after TEVAR for thoracic aortic emergencies.