Intramural Hematoma Without Appreciable Intimal Disruption Imh
First described by Yamada in 198814, intramural hematoma without appreciable intimal disruption IMH is thought to be caused by hemorrhage into the aortic wall from ruptured vasa vasorum as opposed to classic dissection, which is thought to be caused by an intimal tear. However, as denoted above, the concept about the etiology of IMH has not been sufficiently validated. Unfortunately, CT does not allow for direct visualization of the intima if the false lumen is thrombosed and the absence of...
Intramural Hematoma Ijg
Intramural hematoma Figure 4.8 results from hemorrhage into the media from vasa vasorum or from a rupture of an atherosclerotic plaque18'19. This creates a layer of blood clot of varying thickness and varying consistency between the intima and adventitia. The systolic and diastolic force of blood on the vessel wall propels this clot to a varying degree. It can rupture in to the lumen of the aorta or outside through the adventitia. This could lead to either development of a classic dissection or...
Physical Examination
A pulse deficit on clinical examination was found in lt 20 of patients in the IRAD registry and is a poor prognostic sign Figure 3.1 . Pulse deficit was noted more often in patients with type A dissection p 0.006 . Blood pressure may increase or decrease Hypertension is more often an initial presentation in type B aortic dissection 70.1 vs. 35.7 in type A, p lt 0.001 . Hypertension may result from a catecholamine surge or underlying essential hypertension. This is a common concomitant finding....
Diagnostic Criteria Of Aortic Dissection
As with echocardiography and CT, the main criterion used to diagnose aortic dissection by MRI is the presence of a double lumen of the aorta with a visible intimal flap. This feature can be visualized with all pulse sequences commonly used for the examination of the aorta. With cine sequences the movement of the intimal flap can be seen. Differentiation of the true and false lumen is possible with the help of the movement of the intimal flap in systole and diastole Figure 6.2 . A number of...
Trends In Cerebral Protection
The open aortic anastomosis technique represents the most frequently adopted surgical procedure for the distal anastomosis in acute type A aortic dissections1-6. The rationale for this approach has been to identify and remove intimal tears in the arch, perform a more hemostatic anastomosis by avoiding the crowding and distortion induced by the aortic clamp, avoid clamp injuries, and permit a more extensive resection of the dissected aorta at the level of the innominate artery. Concomitantly,...
Streak Artifact
Streak artifact can mimic or obscure dissection of the aorta. Streak artifact is commonly caused by nondiluted contrast in the brachiocephalic vein or superior vena cava SVC Figure 5.2 , metallic foreign bodies Figure 5.2 , and cardiac motion3,6,7 Figure 5.3a-b . Evaluations of the ascending aorta and great vessels off the aortic arch are the most frequently affected Figure 5.3a-b . Contrast injection into the right arm followed by saline flush reduces the concentration of contrast in the SVC...
Magnetic Resonance Imaging in Intramural Hematoma and Penetrating Ulcer of
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
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...
Is it a true dissection or intramural hematoma or penetrating ulcer
Look for thickness of the aortic wall, transducer to anterior aortic wall thickness, site of intimal tear, intimal flap, mobility of the flap, identify true and false lumen, morphology and flow characteristics of the false lumen, atherosclerotic debris, and or ulcer crater. Is the dissection leaking Look for pericardial effusion, distortion of the aortic and main pulmonary artery geometry, hazy echoes in the posterior trigone and transverse pericardial sinus. Increased flow velocity or color...
Prior Cardiac Surgery
Patients who have undergone prior cardiac surgery PCS or invasive cardiac procedures are also at increased risk of aortic dissection. The incidence of acute aortic dissection is 0.03-0.1 after major cardiac surgery, and this incidence is highest for patients undergoing aortic valve replacement AVR 0.5-1.0 . Other conditions predisposing to subsequent dissection include congenitally deformed aortic valve, root aneurysms, redissection, and overlooked annuloaortic ectasia. Symptoms and signs in...
Deceleration And Blunt Trauma
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...
Pregnancy
Pregnancy in a woman with Marfan syndrome is associated with two major risks spontaneous aortic dissection or rupture and transmission of the disorder to the fetus. In most but certainly not all cases of aortic dissection in pregnant women with Marfan syndrome, important aortic root dilatation has been present. In the Murgatroyd series, the mean aortic root diameter in women with Marfan syndrome who developed aortic dissection was 5.1 0.3 cm, compared with 3.7 1.3 cm in women without...
Mri Protocol
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....
LipidLowering 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...
Diagnostic Accuracy
The accuracy of CT for detection of aortic dissection and classification as either type A or type B has been evaluated for single-slice CT, yielding a specificity between 94 and 100 5,13,29,30 and a sensitivity from 93 to 100 1,5,29,30. Moore et al. evaluated the patient records of 628 patients enrolled in the International Registry of Acute Aortic Dissection IRAD between 1996 and 1999, 618 of whom had imaging studies performed1. In this study, CT was more sensitive than transesophageal...
Ct Evaluation Of Aortic Dissection
Clinical Lecturer, Department of Radiology, TC 2910, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0326, USA Department of Radiology, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0326, USA Computed tomography CT is used to evaluate the aorta, specifically aortic dissection, in the following clinical circumstances Diagnosis of acute dissection in patients with the acute onset of chest or back pain or...
Atherosclerotic Disease and Atypical Dissection
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
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,...
Pitfalls
The operator should be familiar with several pitfalls in the evaluation of possible aortic dissection Artifacts mimicking intimal flaps are common in the ascending aorta25,27. They are either side lobe or reverberation artifacts. A side lobe is a curvi- Figure 4.13. This long axis TEE view of the distal arch demonstrates the intimal flap and the entry site. Reprinted with premission. Figure 4.13. This long axis TEE view of the distal arch demonstrates the intimal flap and the entry site....
Magnetic Resonance Imaging 1
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
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
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...
I i Jfll
Figure 17.3. The Djumbodis dissection system is an uncovered stent graft that can be positioned in the aortic arch to facilitate coaptation of the aortic layers. Figure 17.4. Intra-aortic view showing the Djumbodis dissection system superimposed over the origin of the supra-aortic trunks. Figure 17.4. Intra-aortic view showing the Djumbodis dissection system superimposed over the origin of the supra-aortic trunks. serted in the aortic arch during moderate hypothermic circulatory arrest and...
Intimointimal Intussusception
Dissection of the ascending aorta may be missed in the case of an intimo-intimal intussusception, a rare complication of type A dissection, with only a few cases reported in the literature. Intimo-intimal intussusception is caused by a circumferential intimal tear of the proximal ascending aorta, with subsequent prolapse of the torn intima into the true lumen, creating the appearance of a windsock. Because the entire intima is torn off, the ascending aorta can appear normal on CT images, and...
Staging Of Aortic Dissection
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...
Transthoracic Echocardiography
Two-dimensional echocardiography is a useful imaging tool in the initial evaluation of patients suspected of aortic dissection21-23 for both confirming the diagnosis as well as excluding other conditions in patients presenting with similar clinical picture. Although several diagnostic criteria exist Table 4.1 , the hallmark of aortic dissection is the detection of undulating linear echoes of Table 4.1. Echo features that aid in the diagnosis of dissection Linear echo with undulating motion...
Computed Tomography
Helical computed tomography CT is an highly accurate and most frequently selected imaging technique sensitivity and specificity of nearly 100 for the diagnosis of AAD22-26,48,49. It has also been proven to be useful to identify atypical forms of AAD, such as intramural hematoma and atherosclerotic ulcers50,51 . It has important advantages. It is fast and noninvasive, easy to perform, almost always well-accepted by the patient, and not operator-dependent52. It allows three-dimensional...
Annuloaortic Ectasia And Familial Aortic Dissection
More than five mutations in the FBN-1 gene have now been identified in patients presenting with either sporadic or familial forms of thoracic aortic aneurysms and dissection34,35. Histological examination of the aortic wall reveals elastolysis or loss of elastic fibres, deposits of mucopolysaccharide-like materials, and cystic medial degeneration similar to Marfan's syndrome. However, no abnormalities of types I and III collagen or of fibrillin or any specific fibrillopathy were found in...