Diseases of the great vessels





Pseudoaneurysms


CASE 10-1


Aortic pseudoaneurysm after avr with anterior extension


This 41-year-old man with Reiter’s syndrome underwent mechanical aortic valve replacement 9 years ago for aortic regurgitation. Four months ago he developed prosthetic valve endocarditis. He was treated with antibiotics and repeat aortic valve replacement with that procedure complicated by a paravalvular abscess requiring placement of a pericardial patch in the periannular region. Postoperatively, he had persistent paravalvular regurgitation and repeat echocardiography showed “rocking” of the prosthesis and a possible pseudoaneurysm. A preoperative transesophageal echocardiogram demonstrated valve dehiscence with blood flow from the aorta into an anterior echo-free space that also communicated with the left ventricle. He was referred for surgery.



Fig 10.1


Chest radiography shows prominence of ascending aorta. Lateral view demonstrates enlarged ascending aorta with opacification of retrosternal space, and presence of radio-opaque ring of prosthetic valve (arrow) .



Fig 10.2


Chest CT with contrast at level of left ventricle shows abnormal area (arrow) filled with contrast, that communicates anteriorly with LVOT.



Fig 10.3


Chest CT with contrast at level of prosthetic aortic valve (AV). Anterior to prosthetic aortic valve is collection of contrast with irregular borders, which is extraluminal and measuring 2.3 × 4.2 cm. These findings are consistent with aortic pseudoaneurysm.



Fig 10.4


In TEE long-axis plane (at 144 degrees rotation), pseudoaneurysm is seen anterior to prosthetic aortic valve. Color Doppler (right) demonstrates flow in and out of pseudoaneurysm from LV outflow tract.



Fig 10.5


In short-axis TEE view at level of ascending aorta, large echo-free space with irregular borders, consistent with pseudoaneurysm is seen.



Fig 10.6


At surgery, opening aorta revealed orifice of right coronary artery (arrow) just above prosthetic aortic valve (A) . In (B) , anterior aortic wall has been retracted to reveal entrance into pseudoaneurysm (arrow). After removal of anterior aortic wall (C) , very large pseudoaneurysm was appreciated (arrows), originating from underneath right main coronary artery and extending down to middle of noncoronary sinus.




CASE 10-2


Aortic pseudoaneurysm after AVR with posterior extension


12 years prior to admission, this 44-year-old male underwent bioprosthetic AVR for endocarditis. Seven years later he underwent redo sternotomy and second replacement for aortic valve bioprosthesis failure. Four days prior to this admission he developed increasing shortness of breath, and presented to the Emergency Department where examination showed pulmonary edema and lab data including an elevated B-type natriuretic peptide level of 386 pg/mL (Normal <101). TTE and TEE revealed a dilated LV with severe aortic regurgitation and an unstable bioprosthesis with posterior dehiscence and a posterior aortic pseudoaneurysm. His EF was 50-55%. He denied chest pain, syncope, PND, orthopnea, swelling, significant DOE, fevers, chills, nausea, vomiting, diarrhea, and rash. At surgery, the prosthetic valve was explanted, the opening to the pseudoaneurysm patched, and a new bioprosthetic valve placed.



Fig 10.7


This normal anatomic specimen is oriented in the long-axis plane. Note that the fibrous skeleton of the heart is characterized by continuity between the posterior wall of the aortic root and the base of the anterior mitral leaflet. With infection of this region, an aneurysm can form that extends posterior to the aortic root.

(Reproduced with permission from Karalis DG et al: Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Circulation 1992; 86:353–623, 1992 American Heart Association.)



Fig 10.8


Preoperative CT scan. Red arrow indicates valve prosthesis. White arrows indicate posterior pseudoaneurysm, which appears to have two separate areas of fluid collection and impinges on left atrium.



Fig 10.9


Midesophageal short-axis view. In the upper left panel, the red arrow indicates the prosthetic aortic valve, and the white arrow the pseudoaneurysm. The upper right panel shows diastolic flow originating from both the regurgitant valve and the emptying of the pseudoaneurysm into the LV outflow tract. In systole, color Doppler shows the pseudoaneurysm (white arrows) filling from the LVOT, which is indicated by the red arrow.



Fig 10.10


In left panel, midesophageal long-axis view demonstrates area of dehiscence between prosthetic aortic valve and native annulus (red arrow). This suggests that in addition to aortic pseudoaneurysm, patient has aneurysm of aortic-mitral intravalvular fibrosa with additional cavity adjacent to aortic pseudoaneurysm, with communication between these cavities. This is graphically demonstrated in the middle panel. In right panel, color Doppler demonstrates flow between LVOT and pseudoaneurysm (red arrow). (Figure from Zoghbi W: Echocardiographic recognition of unusual complications after surgery on great vessels and cardiac valves. In Otto CM, editor: The practice of clinical echocardiography, ed 3, 2007, Elsevier, p 618.)



Fig 10.11


In these 3D TEE images, dome of left atrium and pseudoaneurysm have been cropped away. At left in diastole, pseudoaneurysm is compressed between aortic valve prosthesis and left atrium. In middle during systole, pseudoaneurysm expands and communication between pseudoaneurysm and LV outflow tract is seen (white arrow). This is seen more clearly in corresponding video clip. On right is normal image for comparison. Note close approximation of aortic and mitral valves in normal heart compared with separation of aortic valve from mitral valve by pseudoaneurysm in this case.



Fig 10.12


From anterior perspective, during systole, aortic valve prosthesis is indicated by three white arrows and pseudoaneurysm by asterisk.



Fig 10.13


Patient was taken to OR. Ascending aortotomy was performed and aortic valve prosthesis explanted. Entry to pseudoaneurysms were patched, and new tissue prosthesis was placed. In midesophageal short-axis view, patches are indicated by arrows. On color Doppler, there is minimal communication seen.



Fig 10.14


In corresponding midesophageal long-axis view, patch again is seen (white arrow). On color Doppler, there was no residual flow between aorta or LV and pseudoaneurysm cavity.




CASE 10-3


Aortic pseudoaneurysm after ascending aortic graft dehiscence


This 43-year-old male originally presented 2 years before the current admission with an acute Type A aortic dissection that originated above the aortic valve and extended to the iliac bifurcation. At that time his ascending aorta was replaced with a tube graft and the native aortic valve preserved. He was readmitted to our institution with chest pain and Staph aureus bacteremia. CT scan revealed a large mediastinal hematoma; anterior and posterior pseudoaneurysms were seen at the proximal end of the aortic graft.



Fig 10.15


PA chest x-ray shows enlarged mediastinum.



Fig 10.16


Long-axis view of aortic valve and ascending aorta shows dehiscence of proximal end of aortic graft, and both anterior and posterior pseudoaneurysms. Color Doppler (right) reveals flow from aorta, through defect and into anterior pseudoaneurysm.



Fig 10.17


This drawing, corresponding to long-axis TEE in Fig 10.16 , demonstrates origin (arrows) of anterior and posterior pseudoaneurysms.



Fig 10.18


3D CT reconstruction shows pseudoaneurysms (arrows) in relation to aortic root.



Fig 10.19


At surgery, large pseudoaneurysm was seen anterior to aortic root.




Comments


A pseudoaneurysm is a contained aortic rupture that may be due to infection of an aortic valve prosthesis with abscess formation and tissue destruction or to dehiscence of a suture line at the anastomosis of an aortic tube graft. At the site of rupture, adhesions and scarring limit the extravasation of blood resulting in a contained space. In most cases, the only communication is from the aorta into the pseudoaneurysm space. However, when valve dehiscence extends both above and below the valve plane, blood enters the pseudoaneurysm from the aorta, and exits into the LV outflow tract, simulating aortic regurgitation. In contrast to a true aneurysm, the walls of a pseudoaneurysm are not composed of aortic tissue. Because a pseudoaneurysm is due to rupture of the aorta, albeit “contained,” treatment is surgical.


Suggested reading




  • 1.

    Evangelista A: Imaging aortic aneurysmal disease, Heart 100:909–915, 2014.


  • 2.

    Ekici F, Kocabaş A, Aktaş D, etin I, Eminoğlu S: Native aortic valve endocarditis complicated by pseudoaneurysm of mitral-aortic intervalvular fibrosa, Echocardiography 31:E60–E63, 2014.





Aortic dissection



Fig 10.20


Stanford, DeBakey, and Penn classification schemes for aortic dissection. In Penn classification, Stanford Type A aortic dissection is integrated with DeBakey I (with descending aortic involvement) and DeBakey II (without descending aortic involvement). Similarly, for Stanford Type B aortic dissection, extension in descending aortic may be in thorax alone (DeBakey III extent A) or in both thorax and abdomen (DeBakey III extent B). Further categorization is based on extension of clinical presentation with postischemic profile: a, absence of ischemia; b, branch vessel malperfusion; c, circulatory collapse; and b and c, both branch vessel malperfusion and circulatory collapse. Within Stanford Type B or DeBakey III, Penn class category may be subdivided into high risk (Type I) or low risk (Type II) of complications depending on echo-anatomic features.

(From Tan CN, Fraser AG: Perioperative transesophageal echocardiography for aortic dissection. Can J Anesth 61:362–378, 2014. With permission.)




CASE 10-4


Ascending and aortic arch dissection


This 57-year-old male patient presented to an outside hospital with the sudden onset of substernal chest pain, described as constant, nonradiating, and worse with movement. He had not had similar pain in the past. He denied trauma, shortness of breath, nausea, vomiting, numbness, tingling, weakness, back pain, abdominal pain, or syncope. His only risk factor for coronary disease was hypertension. He was taken urgently to the cardiac catheterization laboratory for what was suspected acute myocardial infarction and was found to have a normal left coronary system. The right coronary system could not be engaged; however, a dissection flap was seen in the ascending aorta. The patient urgently underwent computed tomographic angiography (CTA) of the aorta demonstrating an acute Type A aortic dissection extending from the aortic sinuses into the ascending aorta, around the arch and down into the descending thoracic aorta. The diameter of the aortic sinuses was severely enlarged at 5.3 cm. At the time of the CTA scan, there was no significant pericardial effusion or involvement of the head vessels. The patient was transferred to our institution for definitive management. At surgery, the aortic sinuses and ascending aorta were resected, and replaced with a composite valve, root, and aortic graft. The coronary arteries were implanted into the graft.



Fig 10.21


Aortic root injection with pigtail catheter (arrow) fails to opacify sinuses, suggesting that catheter is in false lumen of aortic dissection, with aortic sinuses connected to true lumen.



Fig 10.22


Chest x-ray shows widened mediastinum, and obtuse angulation of mainstem bronchi, as result of pressure by enlarged ascending aorta.

(Right image from Minnich DJ, Mathisen, DJ: Anatomy of the trachea, carina, and bronchi, Thorac Surg Clin 17:571–585, 2007. With permission.)



Fig 10.23


In this midesophageal short-axis view, fenestrated dissection flap is seen during systole (arrow, left). In diastole (right), right coronary artery is seen (arrow).



Fig 10.24


In this midesophageal long-axis view, left image clearly shows dissection flap (arrow). In addition, aortic diameter at level of sinuses of Valsalva is enlarged at 5 cm. On right, arrow indicates trace aortic regurgitation.



Fig 10.25


Multimodal imaging of aortic arch. In each instance red arrow indicates dissection flap. Top two images are CT scan as well as 3D reconstructed CT. Middle two images are 3D TEE representations of arch, with color Doppler filling what is presumably false lumen; in real time, undulating motion of flap is appreciated. Lower two images are 2D TEE images of arch; on right, turbulent color Doppler is again filling what is presumably false lumen, which is better appreciated in real time.



Fig 10.26


Reverberation artifact. Left frame: In this high esophageal short-axis image from a different patient, ultrasound is emitted (yellow arrow 1) and reflected off the interface of the anterior wall of the right pulmonary artery (RPA) and posterior wall of the ascending aorta. Most echoes return to the transducer (yellow arrow 2) . Right frame: After ultrasound is emitted (yellow arrow 3) , some returning echoes (red arrow a) are reflected off the posterior wall of the RPA before reaching the transducer. These reflecting echoes (red arrow b) then return to the interface between the anterior RPA and the posterior wall of the ascending aorta before finally returning to the transducer (yellow arrow 4) . The transducer interprets these echoes as coming from a depth equal to the sum of the red and yellow arrows. This artifact (yellow and red asterisk) may be interpreted as aortic dissection flap. With epiaortic scanning, artifact was no longer seen.




Comments


The initial diagnosis of acute aortic dissection often is made with CTA imaging because this modality is rapidly available 24/7 at most medical centers with an ED. Both CTA and MRI are equivalent to TEE in terms of sensitivity and specificity and both have the advantage of allowing evaluation of distal vessels and a wide field of view in the mediastinum. The choice of diagnostic modality in an individual patient often depends on the speed with which the study can be obtained and the expertise of each particular institution. Once the diagnosis is made, the patient is rapidly transferred or moved to the OR with minimal additional interim evaluation.


The echocardiographic diagnosis of aortic dissection is based on visualization of a linear mobile echogenic structure within the aortic lumen, such as the initial flap. It is particularly important to evaluate the ascending aorta because treatment of a dissection that involves the ascending aorta (Type A) is surgery whereas treatment of a dissection limited to the descending aorta (Type B) often is medical.


On echocardiography, imaging artifacts may share some features of an aortic dissection so the echocardiographer should ensure that the mobile intraluminal echo is not due to reverberations. Dissection flaps may be missed if image quality is poor or if there is limited visualization of any aortic segment. The interface between the innominate vein and the aortic arch may be mistaken for a dissection flap. However, with a careful examination by an experienced echocardiography, TEE has a sensitivity of about 98% with a specificity of 98% for diagnosis of aortic dissection.


The TEE performed in the OR thus is critical in defining the exact location and extent of dissection, involvement of the coronary artery ostia, and the presence of a pericardial effusion (implying impending aortic rupture). The TEE also can evaluate aortic valve anatomy to identify those with a bicuspid valve and to evaluate the degree of aortic regurgitation. Even if evaluated before arriving in the OR, the clinical situation changes rapidly with aortic dissection so that reevaluation is critical. The baseline TEE is also helpful in surgical planning: when severe sinus dilation is present as in this case, the possibility of a connective tissue disorder (such as Marfan syndrome) must be considered. These patients require a Bentall procedure with stabilization of the aortic annulus, replacement of the sinuses as well as ascending aorta, valve replacement, and coronary reimplantation. In patients with an ascending aortic dissection but normal sinuses, the native aortic valve may be resuspended at the proximal anastomosis of the ascending aorta graft repair.


Suggested reading




  • 1.

    Tan CN, Fraser AG: Perioperative transesophageal echocardiography for aortic dissection, Can J Anesth 61:362–378, 2014.


  • 2.

    Pape LA, Awais M, Woznicki EM, et al: Presentation, diagnosis, and outcomes of acute aortic dissection: 17-year trends from the International Registry of Acute Aortic Dissection, J Am Coll Cardiol 66:350–358, 2015.



CASE 10-5


Bicuspid valve and aortic dissection


This 50-year-old man presented with the acute onset of bilateral leg weakness and numbness when lifting weights. His initial examination was unremarkable and he was discharged from the ED. Several days later he once again presented to hospital with persistent symptoms, but also with nausea and vomiting and bloody stools. Laboratory work revealed acute renal injury and elevated liver function tests. CTA revealed an aortic dissection flap that extended from the ascending aorta to the iliac bifurcation.


The patient underwent an aortic root and valve replacement using a composite graft with an aortic valve bioprosthesis and coronary reimplantation.



Fig 10.27


In this midesophageal short-axis view, top two frames are in systole. Valve is bicuspid with fusion of right and left coronary cusps. There is raphe (arrow) , partially shadowed. In the bottom two frames during diastole, dissection flap (arrow) prolapses toward, and thus obscures visualization of valve.



Fig 10.28


In this midesophageal long-axis view, left frame shows valve in systole. Valve leaflet is bright calcified structure adjacent to LV outflow tract (LVOT), not complex dissection flap which is indicated by arrows. Dissection flap close to aortic valve can sometimes be mistaken for valve leaflets on CT or TEE imaging. Correct diagnosis can be made by ascertaining insertion site of leaflets into aortic annulus, examining pattern of motion and using color Doppler to identify diagnostic flow patterns. In middle frame, flap (arrow) prolapse through valve during diastole. In right frame, color Doppler indicates flow regurgitating through valve and being somewhat contained by dissection flap (arrow).



Fig 10.29


Sinuses and ascending aorta are both severely dilated with diameter of 5.4 cm.



Fig 10.30


Orthogonal views in aortic arch show serpiginous flap.



Fig 10.31


Flap is seen in descending aorta. Color Doppler pattern makes it difficult to discern which is true lumen and which is false. However, true lumen is usually smaller than the false lumen.



Fig 10.32


Aortic valve in vivo (left) showing fusion of the RCC and the LCC. On the right, the leaflets are seen following explantation. Arrows indicate raphe.



Fig 10.33


Aortic valve and root have been resected. Arrow indicates one of coronary buttons before trimming. (See Fig 10.34 , frame (A) .)



Fig 10.34


In (A) , cross-clamp has been applied, and diseased ascending aorta including sinuses of Valsalva and aortic valve have been resected; all that remains are coronary buttons and annulus. In (B) , valved conduit with tissue bioprosthesis at that distal end, is sutured to aortic annulus. In (C) two holes are made in graft to accommodate coronary buttons, and in (D) , heart with tube graft and one coronary button visible. a = artery.

(From Gleason TG: Aortic root replacement with composite valved conduit, Operat Techn Thorac Cardiovasc Surg 13:161–171, 2008. With permission.)



Fig 10.35


After procedure, there is no aortic regurgitation seen in midesophageal long-axis view. Arrow indicates right coronary button.



Fig 10.36


Similarly, in midesophageal short-axis view, valve is competent.



Fig 10.37


Continuous wave Doppler from transgastric long-axis view shows minimal gradients, consistent with nonobstructive prosthetic valve.



Fig 10.38


Left coronary button is imaged (arrow) and pulsed wave Doppler shows flow during diastole.



Fig 10.39


Right coronary button is imaged (arrow) and pulsed wave Doppler shows flow primarily during diastole.




Comments


A congenitally bicuspid aortic valve is present in 1% to 2% of the entire population. Bicuspid aortic valve disease is not confined to the valve leaflets; the aorta also is abnormal. Histopathologic studies now support an underlying connective tissue disease process with elastin fragmentation, irregularities in smooth muscle integrity, and increased collagen deposition. Compared with normal adults with a trileaflet aortic valve, bicuspid aortic valve patients have larger dimensions of the aortic sinuses and ascending aorta, abnormal aortic elasticity, are at risk for progressive aortic dilation, and have an estimated age-adjusted relative risk of dissection of 8.4 compared with patients with a trileaflet valve, corresponding to an absolute risk of 3.1 cases per 10,000 patient-years. The risk factors for aortic dissection in bicuspid valve patients remain unclear but may include the specific morphology of the valve, in addition to a family history of dissection. In patients with a known bicuspid valve, periodic imaging is recommended for assessment of aortic size either with echocardiography (if the aorta is well seen) or with CT or MRI imaging. Prophylactic aortic root replacement is recommended when aortic diameter exceeds 5.5 cm if there are no other risk factors, and 5.0 cm if there is rapid progression or a family history of dissection.


Suggested reading




  • 1.

    Wojnarski CM, Svensson LG, Roselli EE, et al: Aortic dissection in patients with bicuspid aortic valve-associated aneurysms, Ann Thorac Surg 100:1666–1674, 2015.


  • 2.

    Adamo L, Braverman AC: Surgical threshold for bicuspid aortic valve aneurysm: a case for individual decision-making, Heart 101:1361–1367, 2015.


  • 3.

    Detaint D, Michelena HI, Nkomo VT, et al: Aortic dilatation patterns and rates in adults with bicuspid aortic valves: a comparative study with Marfan syndrome and degenerative aortopathy, Heart 100:126–134, 2014.


  • 4.

    Michelena HI, Khanna AD, Mahoney D, et al: Incidence of aortic complications in patients with bicuspid aortic valves, JAMA 306:1104–1112, 2011.


  • 5.

    Schaefer BM, Lewin MB, Stout KK, et al: The bicuspid aortic valve: an integrated phenotypic classification of leaflet morphology and aortic root shape, Heart 94:1634–1638, 2008.





Complications of aortic dissection


CASE 10-6


Aortic dissection with severe aortic regurgitation


This 44-year-old woman with a history of obesity, hypertension, and diabetes, presented to the ED with chest pain. A diastolic murmur was appreciated on physical examination.



Fig 10.40


PA chest radiography shows wide mediastinum with prominence of aortic arch (arrows).



Fig 10.41


Chest CT with contrast demonstrates enlarged aortic arch with linear density inside lumen consistent with dissection flap (arrows).


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Jan 2, 2020 | Posted by in CARDIOLOGY | Comments Off on Diseases of the great vessels

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