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...

Natural History

It is conventional to consider traumatic aortic rupture to be a highly lethal injury as far as its natural history is concerned. This concept is primarily based on the 1958 historical study by Parmley and associates10, who reported autopsy findings in 296 nonpenetrating TAR. This article has been referred in every subsequent report on this topic and influenced the general opinion over the next 40 years. Remarkably, Parmley's analysis estimated that 85 of the victims died on the scene from free...

References

Beighton P, de Paepe A, Danks D, Finidori G, Gedde-Dahl T, Goodman R, Hall JG, Hol-lister DW, Horton W, McKusick VA, et al. (1988). International Nosology of Heritable Disorders of Connective Tissue, Berlin, 1986. Am. J. Med. Genet. 29 (3), 581-594. 2. De Paepe A, Devereux RB, Dietz HC, Hennekam RC, Pyeritz RE (1996). Revised diagnostic criteria for the Marfan syndrome. Am. J. Med. Genet. 62 (4), 417-426. 3. Shores J Berger KR, Murphy EA, et al. (1994). Progression of aortic dilatation and 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...

Type B

Long-term prognosis of patients with type B IMH is better than in patients with aortic dissection. However, survival at five years reported in different series ranges from 43 to 90 , depending on the population characteristics32,33,42. Several studies have shown important dynamic changes in IMH during evolution, mainly during the six first months31,33,37. Regression occurred within six months in 30 of cases, progression to dissection was observed in 40 , with classical dissection in 12 and...

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...

Etiopathogenesis

Krukenberg, in 19206, first proposed that rupture of the vasavasorum initiated the process of aortic dissection. Gore1 championed this view in the 1950s and suggested that underlying media degeneration predisposed the vasavaso-rum toward hemorrhage and IMH. Rupture of the vasavasorum has been related to the atherosclerotic process and systemic hypertension. Other authors have proposed intimal fracture of an atherosclerotic plaque as the primary event, which then allows propagation of blood into...

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...

Periaortic Structures and Aortic Branch Vessel Origins

Structures immediately adjacent to the aorta for example, the anterosupe-rior pericardial recess or the left brachiocephalic vein can mimic a double lumen and may be confused with dissection Figure 5.4 . The same applies to aortic branch vessel origins, which can simulate the presence of an intimal flap7. Familiarity with the anatomy and, in difficult cases, image review in multiple planes can aid in avoiding these pitfalls. Figure 5.2. Axial contrast-enhanced CT images of classic type A...

Intimal Flap

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...

False Lumen

It is generally large and has slow swirling spontaneous echo contrast. This is due to poor run off from the false lumen. Again morphology and mobility features of the intimal flap as described above are used to identify the false lumen. Often some degree of thrombus is seen in the false lumen. Doppler flow features at the entry site can also identify the true and false lumen. Recognition of the false lumen becomes very important in the arch as well as in the abdominal aorta because of blood...

Conclusions

Considering both the aging patient population in Western societies with prolonged survival despite hypertension and the better diagnostic strategies available to more patients, cardiology and the cardiovascular community face an increasing incidence of acute and chronic aortic problems that desperately need to be stratified using both early biomarkers of an inflammatory and dissecting process and functional imaging of the aortic wall. At this pivotal point in time, an elevated level of...

Initial Diagnostic Tests Ekg Chest Xray Biomarkers

Aortic Arch Aneurysm Chest Ray

The initial chest X-ray may be abnormal in 60-90 of cases and is often the essential first step in making the diagnosis Figure 3.2 Table 3.5 . A widened mediastinum occurs in 62.6 of type A dissection and 56 of type B dissection. An abnormal aortic counter occurs in 45-55 of cases 46.6 type A and 53 type B patients. Other abnormalities include abnormal cardiac contour, displacement calcification of aorta, and pleural effusion. The ECG examination is normal in less than a third of the patients....

Magnetic Resonance Imaging in Intramural Hematoma and Penetrating Ulcer of Aortic Wall

Aortic Penetrating Ulcer

MRI is an ideal tool for the diagnosis of intramural hematoma as well as for visualizing the presence of accompanying plaques. Often an intramural hematoma looks like a half moon, less frequently surrounding the complete circumference of the vessel Figure 11.22 . Furthermore, it is well known that in MRI metabolites of hemoglobin oxihemoglobin, deoxihemoglobin, metahemoglobin, hemosiderin have different magnetic properties. This allows the differentiation between acute bleeding less than 7 days...

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...

Hypotension

Although hypertension is common among those with acute aortic dissection, 12 of those with type A aortic dissection present with hypotension systolic blood pressure 81-99 mmHg and another 13 present in shock systolic blood pressure 80 mm Hg 3. Hemodynamic embarrassment is most often the result of cardiac tamponade or aortic rupture, although in some instances it may result from severe aortic insufficiency. Also, when the measured arterial pressure is low but the patient nevertheless looks...

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...