dissections are managed medical ly.

• Complications of acute dissection include myocardial

infarction, cardiac tamponade, aortic valve insufficiency,

stroke, renal failure, paralysis, limb ischemia, and death.

extend distally (antegrade), proximally (retrograde), or in

both directions. Rarely, the false lumen will rupture

through the adventitia, resulting in immediate hemodynamic collapse. The majority of aortic dissections originate in the ascending aorta (65%), the aortic arch ( 10%),

or just distal to the ligamentum arteriosum (20%). The

Stanford classification system divides aortic dissections

clinically into types A and B. Type A dissections involve the

ascending aorta, whereas type B dissections involve only

the distal aorta (origin of the intimal tear is distal to the left

subclavian artery) (Figure 17-1).

CLINICAL PRESENTATION

..... History

The classic presentation of an acute thoracic aortic dissection is that of a 55- to 65-year-old male with chronic hypertension who develops a sudden onset of severe sharp or

tearing chest pain radiating to the intrascapular area. Keep

in mind that this is a fairly rare condition that often presents

in an atypical manner. When obtaining the history, identify

relevant risk factors and inquire about the quality, radiation,

and intensity at onset of the pain. Type A dissections present

most commonly with anterior chest pain (71 %) and less

commonly with either back ( 47%) or abdominal pain (21 o/o ).

AORTIC DISSECTION

Figure 1 7-1. Stanford classification of aortic

d issections A. Type A. B. Type B. (Reprod uced with

permission from Brunicardi FC, Andersen D, Billiar T,

et al. Schwartz's Principles of Surgery. 8th ed. New

York: McGraw-Hill Education, 2005.)

Additional presenting complaints include syncope (13%)

and stroke-like symptoms (6%). Type B dissections present

most often with acute back (64%) and chest (63%) pain

with increasing rates of abdominal pain (43%). Atypical

presentations include patients with intermittent symptoms,

pleuritic or positional pain, and isolated syncope. Painless

aortic dissections have also been reported. Corresponding

visceral symptoms including diaphoresis, nausea, vomiting,

and pallor are often present.

...,.. Physical Examination

The physical examination should initially focus on the

general appearance of the patient and an assessment of his

or her vital signs. Patients with acute dissections are t ypically very uncomfortable and ill-appearing. Palpate peri ph ­

eral pulses in all 4 extremities and measure the blood

pressure in both arms, taking note of any discrepancies.

The presenting blood pressure cannot be used to either

diagnose or exclude this condition, as roughly half of

patients will have an elevated blood pressure, whereas an

equal proportion will be either normotensive or hypoten ­