1、AOTIC DISEASE1.The Normal AortaAortic AneurysmsAortic DissectionDiseases of the AortaThe Normal AortaThe aorta is divided anatomically into thoracic and abdominal components. The thoracic aorta is further divided into the ascending, arch, and descending segments, and the abdominal aorta consists of
2、suprarenal and infrarenal segmentsIn adults, its diameter is approximately 3 cm at the origin, 2.5 cm in the descending portion in the thorax, and 1.8 to 2 cm in the abdomenThe ascending segment and the point at which the aortic arch joins the descending aorta are most vulnerable parts of the aortaT
3、he Normal AortaThe walls of the aorta are made up of three different layers of tissue: a thin inner layer (intima); a thick, elastic middle layer (media); and a thin outer layer (adventitia)The strength of the aorta lies in the media, which is composed of laminated but intertwining sheets of elastic
4、 tissue arranged in a spiral manner that affords maximal tensile strength. Aortic AneurysmsAortic AneurysmsDefinitionsAortic aneurysm refers to a pathological dilatation of the normal aortic lumen involving one or several segmentsTraditionally for the aorta, any permanently dilated section measuring
5、 4.0 cm or greater in diameter has been called an aneurysm The definition of an aneurysm may also be based on the permanent enlargement of some part of aorta is at least 1.5-2 times greater than normal sizeAortic AneurysmsEtiology and Associated Factors Atherosclerosis Cystic medial necrosis - Marfa
6、n syndrome - Ehlers-Danlos syndrome - Bicuspid aortic valve - Systemic hypertension Aortitis - Rheumatic aortitis - Takayasus arteritis - Giant cell arteritis - Infectious aortiitis TraumaAortic AneurysmsPATHOGENESISMarfan syndromeAtherosclerosisSyphilitic aortitisTraumafibrillin-1 deficiencyexcessi
7、ve TGF-medial dysplasiaMMPs, cathepsins, JNK secrete increasingly medial degradationaortic wall weakenshypertensionaneurysms expansionAortic AneurysmsTypes of aneurysmsthoracic aortic aneurysmabdominal aortic aneurysmthoracoabdominal aortic aneurysmAortic AneurysmsDistributions of aneurysms(60%)40%(
8、30%)(10%)10%60%15%85%descending aorta aneurysmssuprarenal aneurysmsinfrarenal aneurysmsarch aneurysmsascending aorta aneurysmsthoracoabdominal aneurysmsAortic AneurysmsTypes of aneurysmsSaccular aneurysm has more localized dilatation that appears as an outpouching of only a portion of the aortic wal
9、l.Fusiform aneurysm has a fairly uniform shape, with symmetrical dilatation that involves the full circumference of the aortic wall.Pseudoaneurysm which is not actually an aneurysm at all, but rather a well-defined collection of blood and connective tissue outside the vessel wall.Aortic Aneurysms Ep
10、idemiologyAneurysms that originate in the descending thoracic aorta occur at an estimated incidence of 5.9 to 10.4 per 100 000 person-years and rupture at a rate of 3.5 per 100 000 person-years.The incidence of aortic aneurysm rises rapidly after 55 years of age in men and 70 years of age in women.A
11、ortic aneurysms occur 5 to 10 times more frequently in men than in women.Aortic AneurysmsCLINICAL MANIFESTATIONSAsymptomatic Most AAA & 50% TAA are asymptomatic at the time of diagnosis, which are discovered as incidental findings on a routine medical examination.Chest pain or back pain occurs in 25
12、 percent of cases of nondissecting aneurysms and result from direct compression of other cavity structures, or from erosion into adjacent bone. Such pain is steady, deep, boring, and at times severe.Vascular consequences of aneurysm - Impending / actual rupture of aneurysm - Aortic regurgitation fro
13、m dilation of the aortic root, often associated with secondary congestive heart failure - Distal thromboembolismAortic AneurysmsCLINICAL MANIFESTATIONSLocal mass effects of aneurysm- Compression of the superior vena cava or innominate vein cause superior vena cava syndrome.-Compression the trachea o
14、r main stem bronchus and produce tracheal deviation, wheezing, cough, dyspnea, hemoptysis, or recurrent pneumonitis.-Compression of the esophagus can produce dysphagia.-Compression of the recurrent laryngeal nerve can cause hoarseness.Pathognomonic of ruptured abdominal aortic aneurysm - abdominal/b
15、ack pain - a pulsatile abdominal mass - hypotensionAortic AneurysmsPHYSICAL EXAMINATIONBruits arising from associated narrowed arteries can be heard over the aneurysm.Associated occlusive arterial disease is sometimes present in the femoral pulses and distal pulses in the legs and feet.A palpable, p
16、ulsatile mass extending variably from the xiphoid process to the umbilicus.Aortic AneurysmsRisks of aneurysm ruptureAneurysm size Aortic AneurysmsRisks of aneurysm ruptureAneurysm expansion rate 0.5 cm per yearwomen three times more frequently among women than manCurrent smokers Patients with COPD,
17、hypertension, advanced age Aortic AneurysmsDIAGNOSIS AND SIZINGComputed tomography angiography EchocardiographyMagnetic resonance angiographyAortographyChest radiographAortic AneurysmsDIAGNOSIS AND SIZINGComputed Tomography Angiography an extremely accurate method for both diagnosing aortic aneurysm
18、s and sizing them to within 0.2 cmcan better define the shape and extent of the aneurysm as well as the local anatomical relation of the branch vesselsThe limitations include visualization of intimal flap in less than 75% of cases and inability to identify readily the site of intimal tearAdvantagesA
19、ortic AneurysmsDIAGNOSIS AND SIZINGThe CT of shows calcification in the walls of an abnormal aorta. The aorta is dilated from about the level of the first lumbar vertebra and becomes maximal in mid-abdomen. There is a defect in the left wall of the aorta and the lumen extends into the thickened aort
20、ic wall.Aortic AneurysmsDIAGNOSIS AND SIZINGSpiral CT three-dimensional display of aortic aneurysm and information regarding branch arterialsv CTAAortic AneurysmsDIAGNOSIS AND SIZINGEchocardiographyAdvantagesIt can visualize an aneurysm in the transverse and longitudinal planes, has a sensitivity of
21、 87 to 99 percent (depending on the segment involved), and can accurately define aneurysm size to within 0.3 cmIt is limited by less reliable measurements of the suprarenal aorta and significant interobserver variabilityLimitsIt is relatively inexpensive, is noninvasiveAortic AneurysmsDIAGNOSIS AND
22、SIZING Echocardiography of abdominal aortic aneurysmAortic AneurysmsDIAGNOSIS AND SIZINGMagnetic resonance angiographyAdvantagesIt is extremely accurate in determining aneurysm size, and it correctly defines the proximal extent of disease and iliofemoral involvement in more than 80 percent of cases.
23、It is limited by its expensive and uncomfortableLimitsWith the use of MRA, blood has a bright appearance and vessels can be visualized in a projective fashion, similar to traditional angiographyAortic AneurysmsDIAGNOSIS AND SIZINGMRA of thortic aortic aneurysm aortic aneurysmMRI/MRA in a patient wit
24、h asymptomatic thoracic aortic aneurysm. Images in the transverse, A, and longitudinal, B, planes demonstrate a large aneurysm of the ascending aorta (7.8 cm) and moderate dilatation (4.5 cm) of the descending thoracic aorta. Moderate aortic regurgitation is also demonstratedAortic AneurysmsDIAGNOSI
25、S AND SIZINGAortographyAortography had long been the preferred modality for the preoperative evaluation of thoracic aortic aneurysms and for precise definition of the anatomy of the aneurysm and great vesselsPreoperative aortography is now used only in selected cases of abdominal aortic aneurysms be
26、cause CT and MRA provide sufficient information in most cases.Aortography may underestimate aneurysm size in the presence of nonopacified mural thrombus lining the aneurysm wallsAortic AneurysmsDIAGNOSIS AND SIZINGAortography of thortic aortic aneurysm & abdominal aortic aneurysmAortic AneurysmsDIAG
27、NOSIS AND SIZINGChest radiographMany thoracic aneurysms are readily visible on chest radiographs and are characterized by widening of the mediastinal silhouette, enlargement of theoretic knob, or displacement of the trachea from the midlineAortic AneurysmsManagementSurgical repairEndovascular repair
28、Medical treatmentAortic AneurysmsManagementsurgical repairIndicationsPatients wth the presence of symptoms attributable to the aneurysm, posttraumatic aneurysm, pseudoaneurysm,Asymptomatic patients fulfill the below criteria - the ascending TAA or the AAA reach 5.5 cm or larger, and the descending T
29、AA reach 6.0 cm or larger - an abdominal aortic aneurysm less than 5.5 cm in size requires careful routine follow-up to detect either rapid expansion (0.5 cm/yr) or an increase in size to 5.5 cm or largerAortic AneurysmsManagementsurgical repairIndicationsAsymptomatic patients fulfill the below crit
30、eria- In patients with Marfan syndrome, bicuspid aortic valve, or a familial thoracic aortic aneurysm syndrome, given their higher risk of dissection and rupture, we often recommend repair of ascending thoracic aneurysms when they reach only 5.0 cm in size- surgery can be considered even sooner (4.5
31、 cm) in Marfan syndrome patients at especially high risk, such as those with rapid and progressive aortic dilation, those with a family history of Marfan syndrome plus aortic dissection, or women planning pregnancy Aortic AneurysmsManagementEndovascular RepairEndovascular repair of abdominal and tho
32、racic aortic aneurysms has evolved over the past few years and has significantly reduced the morbidity of aortic aneurysm repair compared with the standard open surgical procedures.Endovascular Repair has became the primary method of aortic aneurysm repair in anatomically suitable patients.Aortic An
33、eurysmsManagementDiagram of deployment of an aortic stent graftA.The catheter placement and proximal stabilization are achieved via right femoral access.B.The body and right limb of the stent graft are positioned and deployed.C.The cannula for deployment of the left limb of the graft is placed via l
34、eft femoral access.D.The left limb of the graft is deployed, completing the endovascular repair of the aortic aneurysm with left iliac involvement. Aortic AneurysmsManagementAngiographic views of an infrarenal abdominal aortic aneurysm with bi-iliac involvement treated by stent grafting before (A) a
35、nd following (B) deployment of the aortic stent graft. Aortic AneurysmsManagementMedical treatmentRisk factors modification - Smoking cessation - Hypertension should be carefully controlled. - Hypercholesterolemia should be treatedFollow-up CT scanning every 6 months, perhaps as frequently as every
36、3 months for those at higher risk, has been advocated for follow-up in such patients with an aortic aneurysm 4.0 cm in size or largerAortic DissectionAortic DissectionPredisposing factors Long-standing arterial hypertension - Smoking - Dyslipidemia Connective tissue disorders Hereditary fibrillinopa
37、thies - Marfans syndrome - Ehlers-Danlos syndrome Hereditary vascular diseases - Biscuspid aortic valve - Coarctation Vascular inflammation - Giant cell arteritis - Takayasu arteritis - Syphilis Trauma & Iatrogenic factors Other Pregnancy, Turners syndromeAortic DissectionPathophysiology Aortic diss
38、ection may begin with rupture of the vasa vasorum within the aortic media with the development of an intramural hematoma . Local hemorrhage then secondarily ruptures through the intimal layer and creates the intimal tear and aortic dissection.Aortic dissection is believed to begin with the formation
39、 of a tear in the aortic intima that directly exposes an underlying diseased medial layer to the driving force of intraluminal blood . This blood penetrates the diseased medial layer and cleaves the media longitudinally, thereby dissecting the aortic wall. Aortic DissectionPathophysiologyAortic Diss
40、ectionClassificationTypeSite of Origin and Extent of Aortic Involvement DeBakey Type I Type II Type IIIStanfordType AAcuteChronicType B- Originates in the ascending aorta, propagates at least to the aortic arch and often beyond it distally- Originates in and is confined to the ascending aorta- Origi
41、nates in the descending aorta and extends distally down the aorta or retrograde into the aortic arch and ascending aorta- All dissections involving the ascending aorta, regardless of the site of origin- All dissections not involving the ascending aorta- A dissection presenting less than 2 weeks from
42、 symptom onset- A dissection have been present 2 weeks or more Aortic DissectionClassificationAortic Dissection EpidemiologyThe estimated incidence is about 5 to 30 cases per million per year.About 65% of dissections originate in the ascending aorta, 20% in the descending thoracic aorta, 10% in the
43、aortic arch, and the remainder in the abdominal aorta.There is male predominance with a male-to-female ratio of 2:1 and withpeak incidence in the sixth and seventh decades of life.Aortic DissectionSymptomsPain - 96% of cases - usually in midline of the front and back of the trunk - sudden/abrupt ons
44、et and is severe at onset 85% - tearing or ripping pain(51%), sharp pain (64%) - radiating or migratory pain (jaw, neck, shoulder, or arms) - the return of pain after a pain-free interval is an ominous sign of extension of dissection or impending ruptureSyncope - 13% - more common in type A dissecti
45、ons than type B dissection - pathophysiologic mechanisms include Cardiac tamponade from rupture of AD, Stroke from carotid artery involvement, vasovagal phenomenon associated with intense painAortic DissectionSymptomsDyspnea and symptoms of heart failure usually are secondary to severe aortic regurg
46、itation in this setting (7%)Other symptoms often are related to malpefusion syndromes - Stroke and paraplegia - Anuria - Abdominal pain - limb ischemiaAortic DissectionPhysical findingsHypertension/Hypotension - Hypertension is common and occurs in 70% of type B but in only 36% of type A dissection.
47、 - Hypotension is more common in type A(25%) than type B dissection (4%),which is the result of cardiac tamponade, aortic rupture, or severe aortic regurgitation. - Pseudohypotension can result from compromise of the brachial arteries in dissection involving the brachiocephalic trunk.Pulse deficits
48、- their presence in a patient who has chest pain should raise the suspicion for AAD. - It is more common in type A dissection (19%30%) than in type B dissection (9%21%).Aortic DissectionPhysical findingsA diastolic murmur of aortic regurgitation is present in about one third to one half of patients
49、who have type A dissection.Focal neurologic deficitsSigns of limb or organ ( renal/mesenteric) ischemiaMyocardial ischemia/infarctionSigns of pericardial involvement such as pericardial friction rub, jugular venous distension, and pulsus paradoxus should suggest the possibility of pericardial effusi
50、on/tamponade.Aortic DissectionImagingComputed tomography angiography EchocardiographyMagnetic resonance angiographyAortographyChest radiographAortic Dissection Imaging Computed Tomography Angiography The sensitivity and specificity of CT for the diagnosis of AAD range from 83% to 100% and from 87% t
