Aortic Dissection

Aortic Dissection

• AD is defined as the separation of the layers within the aortic wall; Often blood enters the intima-media space

• Chronological classification• Acute = <2 weeks• Chronic = >2 weeks [a/w better prognosis]

• Classically begin at 1 of the following 3 anatomic locations• Approximately 2.2cm above aortic root• Aortic arch• Distal to the left subclavian artery

2 Major Anatomic Classifications

Stanford• Type A: Ascending

aorta is involved (DeBakey I and II)

• Type B: Descending aorta is involved (DeBakey III)

DeBakey• I: intimal tear occurs

in ascending aorta, but descending aorta is also involved

• II: Only ascending aorta

• III: Only descending aorta

A: Stanford A/DB Type I

B: Stanford A/DB Type II

C: Stanford B/DB Type III

Etiology

• Congenital – Connective tissue disorders– Congenital aortic stenosis– Bicuspid aortic valve – 1st degree relatives with a history of thoracic dissection

• Acquired – Hypertension [70% of patients]– Syphilitic aortitis – Cocaine use – Pregnancy [risk factor]– Iatrogenic causes e.g. cardiology procedures/surgery

Clinical Presentation

• History– Sudden onset of severe chest pain

• Anterior/CP that mimics AMI = a/w anterior arch or aortic root dissection• Intrascapular area = a/w descending aorta

– Neurologic deficits [20% of cases]• Syncope, CVA symptoms

– Others• Respiratory symptoms, dysphagia, abdominal pain,

• Physical Findings– Hypertension/Hypotension, interarm BP difference>20– Aortic regurgitation, hemothorax, cardiac tamponade

Complications• CARDIO

– Aortic rupture = hypotension, shock– Hemopericardium = pericardial tamponade [Type A]– Proximal AD propagating into a sinus of Valsalva = acute aortic regurgitation, pulm

edema– R/L coronary ostium involvement = AMI

• NEURO– Carotid artery obstruction = CVA, spinal cord ischemia

• Mesenteric and renal ischemia – Bowel/visceral ischemia, renal infarction, hematuria, ARF

• Others– Compressive symptoms e.g. dysphagia – Dissection into iliac arteris = claudication – Aneurysmal dilatation and saccular aneurysm

Investigations

• Imaging– CXR = widened mediastinum– CT angiography [definitive test]

Medical Management

• Indications: Uncomplicated Type B • Aims: Reduce BP and shearing forces of

myocardial contractility – To decrease the intimal tear and propagation of

the dissection• Beta-blockers [agents of choice] e.g. labetolol,

propanolol, esmolol

Surgical Management• Indications

– Stanford Type A ascending aortic dissection– Complicated Type B with clinical or radiologic evidence of

• End organ or limb ischemia• Evidence of retrograde dissection to the ascending aorta • Persistent pain• Aneurysmal dilatation greater than 5cm

• Open: Affected areas of the aorta is sutured together, lumen reinforced with a Dacron graft

• Endovascular techniques– Formation of a site or re-entry to allow blood to pass from false lumen to tru

lumen– Perc stenting to decrease ischemic cx of AD– Pec placed intraluminal stent grafts using transfemoral catheter technique

[TEVAR]