The term acute aortic syndrome has been introduced
to the literature and encompasses a number of life-threatening aortic
emergencies.1 These include aortic dissection, penetrating
atherosclerotic ulcer, intramural hematoma, and aortic aneurysmal
leakage or ruptured abdominal aortic aneurysm (see Chapter 63, Aneurysms of the Aorta and Major Arteries).
Acute aortic syndromes are uncommon but frequently fatal. In
a study of 14,000 cases,2 the incidence was 16
per 100,000 for men and 9 per 100,000 for women. The 1-year, 5-year,
and 10-year mortality was 92%, 77%, and 57%,
respectively, for operative patients. Twenty-two percent of cases
were undiagnosed prior to death. The most common cardiovascular
complication of Marfan syndrome is aortic root disease3 and
type A dissection (ascending aorta). Patients with a history of
cardiac surgery are an important subgroup of the dissection population.
Acute aortic syndromes occur in the setting of chronic hypertension
and other factors that lead to degeneration of the media of the
aortic wall. Bicuspid aortic valve, Marfan syndrome, Ehlers-Danlos
syndrome, and familial history of aortic dissection all predispose
to aortic syndromes. All mechanisms involve weakening of the medial
layer that leads to higher intimal wall stress. Response to stress
may include aortic dilation, aneurysm formation, development of
a penetrating ulcer, intramural hemorrhage, aortic dissection, and
Aortic dissection occurs after a violation of the intima allows
blood to enter the media and dissect between the intimal and adventitial
layers. The dissecting column of blood forms a false lumen and may
extend proximally, distally, or both. Blood may dissect and reenter
the intima, and this may clinically suggest a spontaneous cure.
Alternatively the blood may dissect through the adventitia, which
nearly always proves fatal.
Aortic dissection has a bimodal age distribution. The group accounting for
the first peak consists of younger patients with specific predisposing conditions.
The larger group accounting for the second peak is comprised of
those aged >50 years with chronic hypertension. Other atherosclerotic risk
factors appear to be only minor contributors to pathogenesis of
acute aortic syndromes.
Aortic dissections have been classified using two separate systems.
The Stanford classification considers any involvement of the ascending
aorta a type A dissection. Stanford type B dissections are restricted
to only the descending aorta. DeBakey type 1 dissections simultaneously
involve the ascending aorta, the arch, and the descending aorta. DeBakey
type 2 dissections involve only the ascending aorta and type 3,
only the descending aorta.
Krukenberg originally described intramural hematoma in the 1920s.
It has been more frequently described in the surgical and radiology
literature in the last 10 years. An aortic intramural hematoma results
from infarction of the aortic media, usually from injury to the
vasa vasorum.4 An intramural hematoma may resolve
spontaneously or may progress and extend. Intramural hematoma is
often a precursor to dissection.5
Penetrating atherosclerotic ulcer was originally described in
1934 and has also been more frequently described in the last 10
years as imaging quality improves. Penetrating atherosclerotic
ulcer can lead to intramural hematoma, aortic dissection, or perforation
of the aorta.6
Aortic dissections commonly present with abrupt and severe pain
in the chest that radiates to an area between the scapulae. Classically
it is a ripping, tearing sensation accompanied by a feeling of impending
doom. The International Registry of Acute Aortic Dissection7 provides
a valuable insight into the variety of presentations for aortic
dissection. In a case series of 464 dissections, 60% of
patients had anterior chest pain, and the rest had pain in other
locations. Ninety percent felt that the pain was severe or the worst
they had ever experienced. Sixty-four percent described it as sharp
pain and 50% as tearing or ripping pain. Syncope occurred
almost 10% of the time. One hundred of 464 dissections
occurred in patients with prior cardiac sugery.8
Dissections are often a pathophysiologically dynamic process.
Therefore pain patterns and other findings often change, or are
migratory, during the evaluation process. Dissection into a carotid
artery may present as a classic stroke, and many patients with dissection
display neurologic findings. Interruption of blood supply to the
spinal cord may lead to paraplegia. Further distal dissection may
present as back, flank, or belly pain. A proximal dissection to
the aortic root may lead to cardiac tamponade, which is generally
Physical examination may help eliminate some differential diagnoses, but
for most patients with dissection, examination findings are relatively normal.
An aortic insufficiency murmur may occur (32%),7 and
a pulse deficit in radial arteries or femoral arteries can be found
(15%). Hypertension is common (49%), but hypotension
may also occur (18%). Aneurysmal dilation of the aorta
may compress regional structures such as the esophagus, the recurrent
laryngeal nerve, or the superior cervical sympathetic ganglion.
Therefore dysphasia, hoarseness of voice, or Horner syndrome may
The large differential diagnosis for chest pain plus the many
end-organ ischemic manifestations associated with aortic dissections
make the diagnosis challenging. The differential diagnosis includes
myocardial infarction or acute coronary syndrome; pericardial disease;
pulmonary disorders, including pulmonary embolus; stroke; musculoskeletal
disease of the extremity; spinal cord injuries; and intra-abdominal
disorders (Table 62-1).
62-1 Differential Diagnosis of Aortic Dissection
| Save Table
62-1 Differential Diagnosis of Aortic Dissection
|Myocardial infarction or acute coronary syndromes|
|Musculoskeletal disease of the extremity|
|Spinal cord injuries and disorders|
|Pulmonary disorders, including pulmonary embolus, pneumonia,
Ischemic manifestations may change with time (as the dissection progresses),
and this may distract the physician from making the correct diagnosis.
Rupture of the dissection into the true aortic lumen may cause
a cessation of symptoms, and the correct diagnosis may then be inappropriately
dismissed. History, ...