Acute Aortic Dissection

AM Report 6/29/09

Brandon M. Williams, MD

Classification

• Two systems:

• DeBakey

• Daily (Stanford) = most used

DeBakey

• Type 1: origin in ascending aorta and propagates to at least arch

• Type 2: origin in ascending and confined within ascending

• Type 3: origin in descending and extends (distally or proximally)

Daily (Stanford)

• Type A: involves ascending aorta

• Type B: all others

- Nomenclature doesn’t change secondary to site of origin

Daily (Stanford)

Pathophysiology

• Tear in aortic intima• Need degeneration of media or cystic

medial necrosis for nontraumatic dissections

• Blood crosses into media via tear and separates intima from media/adventitia creating a false lumen

• ? If rupture of intima or hemorrhage within media causing rupture of intima is initiating event

Incidence

• Acute aortic dissection

- 2.6-3.5/100,000 person years

Incidence

• Classic is 60 – 80 yo males (mean 63yo)

• Women 67

• Ascending 2x more likely than descending, with right lateral wall most common site

Risk Factors

• 13% with known aortic aneurysm (19% if < 40yo)

• Inflammatory disease vasculitis

-giant cell arteritis

-takayasu arteritis

-rheumatoid arthritis

-syphilitic aortitis

Risk Factors• HTN (71%)• Atherosclerosis (31%)• DM (5.1%)• Collagen disorders (Marfan, Ehlers-Danlos)• 19% of thoracic with family history • Bicuspid aortic valve (9% < 40yo)• Aortic coarctation (post intervention)• CABG• AVR• Cardiac catheterization• Trauma• High-intensity weight lifting and cocaine via transient HTN - cocaine 37% of AA inner city population

Signs and Symptoms

• Abrupt, tearing pain, back (if distal to L subclavian) or anterior (ascending)

• Associated: syncope, CVA, MI, HF• Syncope assoc with worse outcome (almost all type A)• Pulse deficit• Aortic insufficiency: murmur more at RSB than valve

assoc AI (LSB)• >20mmHg difference in SBP between UE• Vocal cord paralysis (compression of L laryngeal nerve)• Hypotension (hemorrhage, tamponade, HF)• Spinal cord ischemia• “STEMI:” 3/820 EKGs showing STEMI found to have

ascending aortic dissection

Images

Images

Images

Images

Diagnosis

• Abrupt onset of pain, tearing/ripping

• Mediastinal/aortic widening on Chest X ray

• Variation in pulse

Imaging

• Chest Xray

• TTE

• TEE

• CTA chest

• MRI

• Coronary angiography

Images

Images

Images

Treatment

• Involvement of ascending aorta = surgical emergency

• Descending aorta: medical management unless progression or hemorrhage into pleural or retroperitoneal space

-morphine -SBP 100-120 or lowest tolerated *beta blocker titrate to HR < 60 (labetalol, propranolol,

esmolol) *if beta blocker intolerant: verapamil, diltiazem *no nitroprusside until HR < 60 *no hydralazine *no inotropic agents, if hypotensive look for bleeding• A-line in radial artery with highest auscultatory pressure

References

• UpToDate• Management of Patients with Aortic Dissection. Weigang

et al. Dtsch Arztebl Int. 2008 Sep. 105 (38) 639-645• Conditions mimicking acute ST-segment elevation

myocardial infarction in patients referred for primary percutaneous coronary intervention. Gu et at. Neth Heart Journal. 2008 Oct: 16 (10) 325-31

• Google images