Penetrating Atherosclerotic Ulcer

Penetrating atherosclerotic ulcers are atherosclerotic lesions of the aorta that penetrate the internal elastic lamina and allow hematoma formation within the media of the aortic wall. The large majority of such ulcerations occur in the descending thoracic aorta, but less often they may occur in the arch or, rarely, in the ascending aorta. The ulcers may progress to form aortic pseudoa-neurysms or, less often, lead to transmural aortic rupture. Table 1.4 summarizes the collective demographics...

Identification Of True And False Lumen

Identification of true and false lumen is an important prerequisite for percutaneous treatment of dissection. In most cases of type B dissection, the true lumen is easily identified by its continuity with the nondissected ascending aorta. However, in type A dissection and in cases where the aorta is incompletely imaged, identification of true versus false lumen may not be straightforward. The following imaging criteria are helpful to distinguish between true and false lumen33-35. The beak sign...

Natural History

Natural history of acute aortic syndrome is best outlined prognostically by differentiating patients into those with involvement of the ascending aorta (type A) versus individuals with acute pathology confined to the distal arch and the descending aorta (type B). This distinction is notable for the differing risk factors for development of dissection and also for the critical proximal branch vessels and anatomic details affecting patient outcomes acutely and chronically by virtue of...

Thoracic Aortic Aneurysms

Anatomically the thoracic aorta is divided into a several distinct segments (Figure 1.1). The ascending aorta extends from the left ventricle (at the aortic annulus) and rises in the anterior mediastinum to the innominate artery. The base of the ascending aorta is referred to as the aortic root. The root is the widest aortic segment and is comprised of three coronary sinuses, which bulge outward, and serves as the support structure for the aortic valve cusps. The portion of the ascending aorta...

Etiology Of Aortic Dissection

All mechanisms weakening the aorta's media layers via micro apoplexy of the vessel wall lead to higher wall stress, which can induce aortic dilatation and aneurysm formation, eventually resulting in intramural hemorrhage, aortic dissection, or rupture (Table 2.1). Thus, besides the chronic trauma resulting from arterial hypertension (which represents the major reason and mechanism for stress to the aortic wall), three inherited connective tissue disorders are currently known to affect the...

Aortic Dissection

The true incidence of acute aortic dissection is difficult to determine, as many cases may go undiagnosed, but its documented incidence is approximately 2.9 per 100,000 per year, with at least 7,000 cases per year in the United States15. A healthy aorta with an intact medial layer rarely dissects. Alternatively, those in whom the integrity of the media is compromised are at risk for aortic dissection. Therefore, any disease process or condition that damages the elastic or muscular components of...

Surgical Spinal Cord Protection

The role of the perfusion of the distal aorta in preventing ischemic damage of the spinal cord and renal failure during surgery for traumatic aortic rupture has yet to be clarified. All surgical techniques that imply the use of aortic clamping at the level of the descending aorta disrupt the balance of blood pressure. Above the cross-clamp, a hypertensive regimen is established with an overload of work for the left ventricle below, a low blood pressure is established with ischemia that...

Triggers Of Dissection

Aortic dissection and its variants originate at the site of the intimal fear in gt 95 of cases. Primary rupture of the inner aortic lining or rupture of the vasa vasorum of the aortic wall with initial intramural bleeding and secondary rupture are the two initiating mechanisms of acute aortic syndrome. The trigger to the initiating lesion, however, is any kind of specific trauma, which may be due to blunt macrotrauma or deceleration injury or repetitive chronic microtrauma of pulsatile aortic...

Intimal Flap

Initimal Flap Aorta

It is easily recognized as a linear echo of varying thickness. It is usually thin lt 2 mm in acute dissections and thick gt 4 mm due to neo intima formation on the false lumen side, in chronic dissections. When there is uncertainty as to which is the true and which is the false lumen, intimal flap mobility as assessed by M-mode echo can be helpful. The movement of the intimal flap depends on the extent of separation and the blood flow dynamics in the true Figure 4.6. TEE short axis image of an...

Endovascular Treatment

Aortic Dissection Uncovered Stent

Since 1996, the introduction of endovascular techniques for the thoracic aorta in the clinical practice has opened less invasive options for patients in which emergency treatment is necessary. After initial limited series and case reports, endovascular treatment is evolving as the method of choice in management of TAR71-74. Because of the lower invasivity, avoiding thoracotomy, and the use of heparin, endovascular repair can be applied in the acute patients without the risk of destabilizing...

Deceleration And Blunt Trauma

Traumatic Aortic Dissection Deceleration

Traumatic aortic rupture is an infrequent but not rare event. Trauma represents the leading cause of death of individuals in the United States under the age of 40, with aortic rupture trailing only head trauma as the most frequent cause of death. Deceleration trauma from automobile accidents, fall from height, blast injuries, or injuries during downhill skiing or equestrian accidents appear to be the primary mechanism. In a demographic analysis of 144 patients with aortic rupture, 83 were...

Mri Protocol

Aortic Dissection

The elements of the standard imaging protocol used at the Robert-Bosch Hospital are shown in Table 6.3. Continuous monitoring of blood pressure and ECG is performed. Special infusion systems are used if continuous intravenous medication is given. If imaging in a mechanically ventilated patient is necessary, a ventilator with special tubing is in place. As a first step, transverse, coronal, and sagittal 2D localizer images are acquired using an ultrafast breath hold echo-planar CMR technique....

Lipid Lowering Therapy

Kertai et al. assessed the potential long-term beneficial effects of statin use after successful abdominal aortic surgery and demonstrated that long-term statin use is associated with reduced all-cause and cardiovascular mortality irrespective of clinical risk factors and beta-blocker use7. After adjusting for clinical risk factors and beta-blocker use, the association between statin use and reduced all-cause hazard ratio HR 0.4 95 , confidence interval CI 0.3 to 0.6 p lt 0.001 and...

Atherosclerotic Disease and Atypical Dissection

Aortic Intraluminal Thrombus

On contrast-enhanced CT, IMH has the appearance of a nonenhancing low attenuation rim or crescent, which can be difficult to distinguish from atherosclerotic intraluminal thrombus Figure 5.5c-f . Three imaging characteristics are useful to differentiate between IMH and intraluminal thrombus First, the false lumen of acute IMH shows high attenuation on unenhanced CT intraluminal thrombus does not. However, this imaging criterion becomes unreliable in subacute and chronic intramural hematoma...

Ischemic Complications

Aortic Dissection Static Occlusion

On CT, the finding of a filiform true lumen and a large false lumen suggests one of the most dreaded complications of aortic dissection namely, compression of the true lumen by an expanded false lumen55-58 Figure 5.18 . Compression may be static or dynamic, depending on whether the expanded false lumen is thrombosed or perfused. Branch vessel occlusion, occlusion of the distal aorta, and subsequent ischemia are the consequences. Accordingly, impairment of branch vessel perfusion can be static,...

Magnetic Resonance Imaging

The role of MRI in diagnostic evaluation of aortic diseases has been widely documented, resulting in comparative studies as one of the most accurate diagnostic techniques in the detection of acute and chronic aortic pathology55. A long examination time as well as difficult access to the patient has been considered the main limitation in acute aortic pathology. Although the development of fast MRI techniques has enabled the examination to be shortened to a few minutes, MRI has been underutilized...

Actual And Future Management In Arterial Perfusion

Supra Aortic Dissection

The selection of the arterial cannulation site for institution of cardiopul-monary bypass is a critical point during surgery for acute aortic dissection. Historically, in these patients the femoral artery has been adopted as primary site for arterial access15. However, a number of relevant complications have been associated with this procedure, including propagation of a retrograde dissection, retrograde embolization of lumen debris, and malperfusion causing end-organ ischemia16-18. In...

Indications For Stent Placement And Fenestration

Tevar Endovascular Radiology

The exact role of percutaneous fenestration and stent placement in the treatment of aortic dissection continues to evolve. In dissection, there appears to be a role for stent-graft placement in the treatment of static or dynamic obstruction of aortic branch arteries because static obstruction of a branch can be overcome by placing endovascular stents across the vessel origin, and dynamic obstruction may benefit from stents in the aortic true lumen with or without additional balloon...

Staging Of Aortic Dissection

Aortic Dissection Pau

The Stanford classification of aortic dissection distinguishes between type A and type B Figure 2.1 36,37. Type A means the dissection involves the ascending aorta a type B dissection does not involve the ascending aorta. This distinction or description is applied in similar fashion to all acute aortic syndromes, including all variants of dissection such as intramural hematoma and penetrating aortic ulcerations. The De Bakey classification subdivides the dissection process in type I dissection...

Reduction Of Dpdt And Treatment Of Hypertension

The primary objectives of pharmacological therapy are the reduction of the rate of rise of systolic aortic pressure due to left ventricular ejection of blood dp dt and the lowering of the systolic blood pressure. Such medical therapy is accepted as the initial treatment for virtually all patients in whom aortic dissection is suspected, even before a definitive diagnosis is made, and should be continued thereafter once the diagnosis is confirmed. All patients with acute aortic dissection should...