Aortic Dissection

From: iradonline.org/images/aorta-layers.gif

Types of Aortic DissectionsStanford Classification

Type A = involves ascending aorta

Type B = does not involve ascending aorta

DeBakey Classification

Type I = ascending and descending aorta

Type II = ascending aorta only

Type III = descending aorta only

From: www.massgeneral.org/tac/patients/diseases.asp?id=a_dissection

Aortic Dissection Risk FactorsTypically: Systemic Hypertension Systemic Hypertension Did I mention systemic hypertension?

Present in 60-90% of patients

In younger patients, must consider other factors: Bicuspid aortic valve (9% under 40 in one review) Inflammatory disease (giant cell, syphilitic aortitis, RA, etc.) Collagen Diseases (ED Syndrome, Marfan’s (50% in those under 40 in one

review)) Preexisting aortic aneurysm Coarctation

Others: CABG Trauma Iatrogenic (intravascular procedures) Cocaine use (thought to be catecholamine mediated)

Clinical Manifestations/FindingsAcute onset of tearing chest pain, frequently

radiating to the backSyncopeAsymmetric BP in UEWeak/absent peripheral pulsesAortic Insufficiency/Heart FailureMIRenal failureParaplegiaBack PainPericardial effusion

Many different presentations; how to diagnose clinically?

One relatively small study found that in 250 patients with acute chest and/or back pain, certain findings were particularly relevant: sudden onset of tearing/ripping chest pain, widening of mediastinum or aorta (or both), and pulse or BP differentials (or both).Absense of all three, low probability (7%)Characteristic chest pain, intermediate probability

(31%)Mediastinal Widening, intermediate probability (39%)Pulse/BP differential, high probability (>83%)Combination of all three, high probability (>83%)

Bottom line is that you need imaging to assist in

the diagnosis

Imaging StudiesCXR: abnormal in majority of patients (90%

sensitive), but cannot rule out dissection (although completely normal imaging is helpful)

CT: up to 98% sensitive and up to 100% specific (depending on the study)

TEE: up to 98% sensitive 95% specific

MRI: sensitivity & specificity >98%

Aortography: sensitivity <90%

Acute ManagementRisk of death for untreated acute dissection is

estimated at 1% per hourIV antihypertensives (goal of SBP <120 or lower if

tolerated) and negative ionotropic agents (goal HR < 60)

Pain controlCardiac monitoring, preparation for aggressive

resuscitation Ultimate goal initially is to prevent death and

irreversible end-organ damage

From: www.ajronline.org/cgi/content-nw/full/183/1/109/FIG1

Definitive TherapyAscending Dissections Surgery ASAP

Descending DissectionsIf stable and uncomplicated: managed

medicallyIf unstable or complications: surgery

Subsequent ManagementBlood pressure control… the lower, the

better

Serial imaging with MRI/CT on annual basis to evaluate for aneurysm formation, anastomotic leakage, recurrent dissection

Consideration of second operation to repair aforementioned complications