Tran and Khoynezhad FALSE LUMEN TRUE LUMEN Figure 4 Computer tomography with enhanced contrast showing type B dissection. Figure 5 Intravascular imaging of aortic dissection. If the diagnosis can not be established using the aforementioned imaging modalities, the patient should be taken to the hybrid operating room. An intravascular ultra- sound and/or aortography performed by the cardiothoracic surgeon will establish the deﬁnitive diagnosis (similar to diagnostic algorithm of traumatic aortic transection).27 Intravascular ultrasound (IVUS) is a novel approach in diagnosis of type B AAD that has the highest accuracy of any modality (Figure 5). IVUS has been demonstrated 100% sensitivity and speciﬁcity during endovascular diag- nosis and treatment of complicated type B aortic dissec- tion.28 Furthermore, IVUS is a critical imaging modality for endovascular treatment options for type B AAD.29 Management The modern surgical treatment for AAD, including those for acute type B aortic dissection, began after the landmark aortic operation by Drs Cooley and DeBakey in the 1950’s.30 In the decades following this sentinel event, patients with type B aortic dissection were mostly treated surgically. The medical management of acute type B AAD began to gain credence with the concept of antiimpulsive therapy as described by Wheat.31 He was one of the ﬁrst to demonstrate the impor- tance of the force of contraction (dP/dtmax) and blood pres- sure in the propagation of AAD in a dog model.32 Starting in the early 70’s, medical management of uncomplicated 60 type B AAD increasingly became the standard of care due to availability of potent beta-blockers and the lower mortality compared to surgical approach (for type A, early mortality rates of 10% vs. 35%, respectively).33 Today, the antiimpulsive and antihypertensive combination therapy remains the cornerstone of modern medical management of type B AAD. Table 2 illustrates the authors’ approach to the diagnosis and management of an acute aortic dissection (AAD) in the ED. At triage, patients who present to the ED with sudden onset of chest, back, or abdominal pain should be quickly brought to a room to be examined by a physician. Prompt diagnosis and treatment of patients with suspected AAD is essential for improved outcome. The abbreviated history and physical examination should focus on time of onset, risk factors for aortic dissection, and ﬁndings that are consistent with AAD (Table 2). Patients should have IV’s and A-line established, supplemental oxygen, be put on a cardiac monitor, an EKG, portable chest X-ray, blood draws, and be typed and crossed for 10 units of PRBC’s. Surgical consultation should be initiated as soon as the emergency physician is comfortable with his/her clinical impression. Pain should be treated with appropriate analgesics (eg, morphine). Heart rate and hypertension should be aggressively controlled with β-blockers.34 An arterial Vascular Health and Risk Management 2009:5