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Thoracic Aortic Aneurysms& Aortic Dissection

Prof. Moaath Al-Smady.

Division of Cardiothoracic/Vascular surgery – Department of SurgeryUniversity of Jordan

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◼ Introduction

◼ Definition

◼ Anatomy

◼ Natural History

◼ Risk factors

◼ Presentation

◼ Diagnosis

◼ Management

◼ Open repair vs. EVAR

◼ Complications

Presentation’s Outline

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Introduction

◼ Aneurysm and dissection are the most common diseases of the aorta.

◼ Definition : localized or diffuse aortic dilation that exceeds 50% of the normal aortic diameter

◼ Elasticity and tensile strength from the medial layer → containselastin, collagen, smooth muscle cells, and ground substance→Genetic Factors

◼ Cystic medial degeneration → leads to the final common pathway of progressive aortic expansion and eventual rupture

◼ The vicious cycle → Laplace's law (tension = pressure ´ radius)

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AnatomyThe proximal aortic segment

◼ Ascending → from aortic valve (and the three sinuses of Valsalva ) till the origin of the innominate artery

◼ Transverse aortic arch→brachiocephalic branches

The distal aortic segment

◼ Descending thoracic aorta → distal to left subclavian artery till the diaphragmatic hiatus → multiple bronchial and esophageal branches as well as the segmental intercostal arteries, which provide circulation to the spinal cord.

◼ Abdominal aorta.

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Natural History and Incidence

◼ No prospective or randomized analyses of the natural history..

◼ incidence 10./100,000 person-years

◼ Aortic diameter was a strong predictor of rupture, dissection, and mortality.

◼ Critical diameters→ 6.0 cm ( ascending aorta, 31% mortality) and 7.0 cm ( descending aorta, 43% mortality ).

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Risk Factors

◼ Advanced age◼ Hypertension◼ Smoking◼ Arteriosclerosis◼ Aortic dissection◼ Bicuspid aortic valve ◼ Connective tissue disorders (Marfan’s)◼ Trauma◼ Male Gender / Family Hx◼ Diabetes◼ Heart transplants

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Clinical Manifestations ◼ Asymptomatic

◼ Pain implies sudden extension or rupture of aneurysm- Ascending aorta - neck, jaw- Descending aorta - back, inter-scapular- Thoracoabdominal aorta - low back

◼ Compression of adjacent structures- SVC syndrome

- Hoarseness, laryngeal nerve

◼ Erosion ◼ Aortic Valve Insufficiency ◼ Distal Embolization◼ Rupture

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Complications of aneurysms

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Diagnosis

◼ Hx and P/E

◼ Plain Radiographs

◼ ECHO

◼ CT scan

◼ MR Angio

◼ Aortogram and Cardiac Cathetrization

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Plain Radiographs

◼ convexity in the right superior mediastinum

◼ loss of the retrosternal space

◼ widening of the descending thoracic aortic shadow( calcification )

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Echocardiography

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CT scan

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Aortography and Angiogram

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Medical Management

◼ Life Style Modification

◼ Smoking Cessation

◼ BP Control

◼ Beta-blockade with Propanolol

◼ Periodic Exams

◼ CT if close to surgical threshold

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Indications for surgery

◼ Ascending◼ signs of AI◼ Acute or Chronic Dissection◼ Rupture◼ Progressive enlargement◼ Marfan's pt. with size > 5 cm

◼ Arch◼ All symptomatic patients

◼ > 5-6 cm fusiform aneurysms

◼ All pseudoaneurysms

◼ Descending/ Thoracoabdominal◼ all symptomatic patients◼ twice the normal size of the aorta or 6 cm.◼ progressive enlargement (> 1 cm/yr)

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Ascending aortic aneurysms

◼ All under cariopulmonary bypass . ◼ Healthy aortic valve, annulus, and

sinuses of Valsalva → simple dacron graft.

◼ Sinus of Valsalva aneurysms with normal aortic valve leaflets and aortic insufficiency due to dilated sinuses →aortic root sparing .

◼ Mechanical vs procine. ◼ --------------------------------------◼ Ascending aortic replacement ◼ Valve-sparing aortic root replacement ◼ Aortic root replacement ◼ Open distal anastomosis

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Bentall technique

The coronary ostia are tightly sutured to openings in the graft.

Aortic arch aneurysms

◼ Deep hypothermic circulatory arrest (HCA) ( antegrade or retrograde cerebral perfusion)

◼ Hemiarch replacement

◼ Trifurcated head-vessel attachment graft.

◼ Staged procedure→ “elephant trunk” → sleeve → facilitating later replacement of the

descending thoracic aneurysm.

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Surgical repair of the arch

A–H, Surgical technique for total arch replacement with a branched aortic graft. Following initiation of circulatory arrest, the aneurysm is transected in the ascending aorta and where it meets the proximal descending aorta. The branched graft is anastomosed at its distal end. The graft proximal to the fourth limb is clamped and perfusion is restored through this limb to the distal circulation. The third limb is anastomosed to the left subclavian artery and flow to this vessel is restored.Then, the proximal end of the graft is anastomosed to the stump of the ascending aorta, flow is restored to the remaining arch vessels, and the fourth branch is then resected

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Descending thoracic aortic aneurysm

Type A, distal to the left subclavian artery to the 6th intercostal space. Type B, 6th intercostal space to

above the diaphragm (12th intercostal space). Type C, entire descending thoracic aorta, distal to the left

subclavian artery to above the diaphragm (12th intercostal space).

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Descending thoracic aortic aneurysms and thoracoabdominal aneurysms

◼ Either open or endovascular repair.

◼ With or without the use of a bypass circuit

◼ Endovascular stent grafts → Gore-TAG (lt subclavian → celiac).

◼ Thoracoabdominal aneurysms → may be repaired with the use of a partial bypass of the left atrial artery to the femoral artery.

◼ Prevention of paraplegia is one of the principal concerns.

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Surgical complications

◼ Bleeding

◼ Stroke ( arch repairs )→hypothermic circulatory arrest.

◼ Myocardial infarction

◼ Pulmonary dysfunction

◼ Renal dysfunction

◼ Paraparesis and paraplegia

◼ Endovascular stenting complications : endoleaks, stent fractures, and stent graft migration.

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OUTCOME AND PROGNOSIS

◼ (1) Ascending aneurysms repair mortality → 4-10%

◼ (2) Arch aneurysms repair mortality→ 25%

◼ (3) Descending thoracic aneurysms repair mortality →5-15%,.

◼ (4) survival rates after surgery for chronic AAs are approximately 60% at 5 years and 30-40% at 10 years.

◼ (5) GORE-Tag → 1.5% 30 day mortality. Temporary or permanent spinal cord paraplegia occurred in 3% of patients and stroke in 4% of patients. At 2 years, aneurysm survival was 97% and overall survival 75%

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(1) Culliford et al from 1982, Cabrol et al from 1988, and Donaldson and Ross from 1982

(2) Crawford and Saleh from 1981, Crawford et al from 1979, Columbi et al from 1983, Ergin et al from 1982, and Galloway et al from 1989

(3) Crawford et al from 1981, Donahoo et al from 1977, Livesay et al from 1985, and Pressler and McNamara from 1985

(4) Crawford et al from 1978, Crawford et al from 1981, and Kitamura et al from 1983

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Endovascular stents

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Endovascular stents

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Aortic Dissection

◼ Tear in the intima of the aorta resulting in blood leaving the normal aortic channel and dissecting through the media producing a false channel

◼ True and false lumens separated by intimal flap

◼ Fenestrations in intimal flap produces flow in both lumens - double barrel aorta

◼ Possible compromised flow to branches of aorta (organs and extremities)

◼ False lumen weakens with time – aneurysm or rupture

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Proposed mechanisms of initiation of aortic dissection

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◼ Hospital death: as a consequence of

hemorrhage, myocardial infarction, stroke, visceral necrosis, renal failure

◼ Ascending aorta 5-10% (to 30%)

◼ Arch 10-25% (to 50%)

◼ Descending 10% (to 25-60%)

Aortic Dissection Complications

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Aortic dissection classification based on the site of the intimal tear

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Aortic Dissection

◼ Typically in 50-70 year old men with Hypertension◼ Connective tissue disorder◼ Severe pain (90%) :tearing, interscapular, precordial or neck

◼ Aortic Murmur – dissection causing incompetence◼ Cardiac Tamponade – rupture into pericardium

◼ Signs of occlusion of major branch vessels◼ Coronary – hypotension and chest pain◼ Arch - stroke – rarely improves with restoration of flow◼ Intercostal - paraplegia◼ Renal - oliguria-anuria◼ Visceral - acute abdomen◼ Iliac - ischemic leg – pulse deficit (60%)

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Diagnosis

◼ Chest X-ray - widened mediastinum, cardiomegaly, pleural effusion

◼ Aortogram

◼ TEE

◼ 2-D ECHO - identifies intimal flap/false channel, noninvasive, no contrast media, bedside

◼ CT Scan - identifies intimal flap rapidly, requires contrast media, identifies rupture

◼ Digital Subtraction Angio

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CXR

Chest radiograph of a patient with aortic dissection. A, The patient's baseline study from 3 years prior to admission, with a normal-appearing aorta. B, The chest radiograph upon admission, which is remarkable for the interval enlargement of the aortic knob (arrow). The patient was found to have a proximal aortic dissection

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Aortogram

Aortogram in the left oblique view demonstrating proximal aortic dissection and its associated cardiovascular complications. The true lumen (T) and false lumen (F) are separated by the intimal flap (I), which is faintly visible as a radiolucent line following the contour of the pigtail catheter. The true lumen is better opacified than the false lumen, and two planes of theintimal flap can be distinguished (arrows). The branch vessels are opacified, along with marked narrowing of the right carotid artery (CA), which suggests that its lumen is compromised by the dissection

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TEE

Transesophageal echocardiography of dissection of the ascending aortic

aorta in cross-section (A) and saggital color-Doppler mode view demonstrate

no flow in the large false lumen (B).

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2D-ECHO

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Type A aortic dissectionCT scan

CT scan of type A aortic dissection with intimal flap in the ascending (A) and

descending (B) segments of the aorta.

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CT scan of type B aortic dissection with normal ascending aorta (A) and multiple

partitions of the lumen in the descending thoracic aorta (B)

Type B aortic dissection

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Management of Aortic Dissection

• Medical– Uncomplicated Type B

– Control pain

– Control BP

• Surgical– All Type I’s and II’s (Type A)

– Complicated type III’s (Type B)– leak, limb or gut ischemia, acute renal failure,

paraparesis, uncontrolled pain

– Contraindicated in equivocal CNS, advanced age, limiting comorbidities, +/- paraplegia

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Ascending aortic dissection repair

Ascending aortic dissection repair. A, Proximal tear site, aortic valve inspection, intima and adventitial suture, inner distal

anastomosis with pledgeted polypropylene suture reinforcement. B, Outer distal anastomosis with pledgeted polypropylene

suture reinforcement, aortic valve resuspension, and proximal reinforced anastomosis.

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Surgical treatment

A, Operative photograph of acute type A aortic dissection with hematoma in the aortic wall. B, After opening the aorta, a

large clot was cleared from the false lumen; true lumen (L) is seen after division of the intimal flap. RA, right atrium; the

asterisks indicate Rumel tourniquet around superior vena cava.

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Thank you