Thoracic Aortic Dissection Flashcards
What genetic syndromes are associated with this?
Genetic syndromes that place patients at increased risk of thoracic aortic dissection include Marfan syndrome, Loeys-Dietz syndrome, Turner syndrome, and Ehlers-Danlos syndrome (vascular type).
Describe the classification schemes
Simply put, Stanford type A dissections involve the ascending aorta, while Stanford type B dissections do not.
Debunked. Type I involves Ascending and Descending. Type II involves only Ascending. Type III involves only Descending.
Pathology
true aortic dissection in which a tear in the aortic intima permits entry of blood into the media (Figure 2). Pulsatile flow into the rent created by the tear propagates proximally and/or distally along the length of the aorta
What BP changes would indicate this diagnosis?
The presence and strength of pulses in all four extremities should be determined, and this should be accompanied by measurement of bilateral upper extremity blood pressures with increased concern for thoracic aortic dissection when a systolic BP differential of greater than 20 mmHg between arms is obtained.
What if the patient has a STEMI
Particular caution is advised at this stage, as a 12-lead ECG diagnostic of an ST-elevation myocardial infarction does not exclude concomitant aortic dissection. A type A dissection may indeed be the cause of the STEMI.
What is the classic and non classic presentation
The classic patient will be a male in his 60s with a history of chronic hypertension who presents with “sharp,” sudden-onset, severe chest pain that radiates to the back.
Classically, this pain is sudden-onset and may radiate to the interscapular area of the back (i.e., “between the shoulder blades”) or to the abdomen and low back, depending on the location of the dissection. The pain is typically the most severe the patient has experienced and often described as “sharp,” “ripping,” or “tearing” in quality.
How does Type A vs Type B present differently?
Type A dissection is more likely to cause chest pain or syncope and less likely to cause back or abdominal pain when compared to type B dissection. Patients with type B dissection are about two times as likely to present with hypertension (SBP ≥150 mmHg), whereas type A dissections are many times more likely to cause hypotension (SBP
CXR findings, how many with dissection have a normal CXR?
40%
Widened mediastinum (>8 cm at aortic knob)
Abnormal aortic or cardiac contour
Displaced intimal calcification
Widened right paratracheal stripe (≥5 mm)
Tracheal deviation (usually rightward)
Opacified aortopulmonary window
Pleural effusion (usually left)
Best imaging modality?
In stable patients, CTA is the most commonly employed imaging study used for ruling aortic dissection in or out
Near 100% specific and sensitive
Because end-organ perfusion is a concern in patients with acute aortic dissection, the ability of this modality to directly assess for compromised perfusion to the gut, kidneys, brain, or lower extremities is advantageous.
What is the only lab test that may be reasonably promising?
The only lab test that has been reasonably studied and shows any promise as a screening tool for thoracic aortic dissection is D-dimer.
however not good for screening
How does treatment differ from type A vs type B?
Type A dissections require emergent surgical repair, while type B dissections are largely managed medically in the acute phase. “Complicated” type B dissections (see below), which occur in 20-30% of patients, may be managed medically or by open surgical or endovascular techniques
What other general treatment should be done?
Control pain. Humane and dec BP and HR
No consensus, but…
Keep HR below 60 if possible with Beta Blocker (Esmolol) or secondary Ca channel blocker.
Keep BP below 120 if possible with venous vasodilator (Sodium nitroprusside or Nicardipine).
What makes a type B complicated?
When end-organ perfusion is compromised (e.g., intestinal ischemia, spinal cord ischemia, renal malperfusion), hypertension is refractory to medications, the dissection continues to propagate despite medical interventions, or the aorta exhibits aneurysmal expansion, open surgical or endovascular procedures may be indicated.
What should you do before giving vasodilators to control BP?
Vasodilators should not be initiated prior to rate-controlling agents, as they may result in reflex tachycardia that serves to propagate the dissection.
