Master the board step 3

Cardiology
Aortic dissection cases should be placed in the ICU, and a surgical consultation
should be ordered. Surgical correction is the most effective therapy.
Abdominal Aortic Aneurysm (AAA)
Screening with an ultrasound should be ordered in over-65 men who were
smokers.
Abdominal aortic
aneurysm is detected by
ultrasound first. AAAs are
repaired when they are
> 5 cm. Smaller ones are
monitored.
Basic Science Correlate
As an aneurysm enlarges, the rate of expansion increases: Wider aorta =
Widens faster.
This principle is expressed in the law of LaPlace: Wall tension = Radius ×
Pressure.
Next step: Lower BP and repair with stent or endovascular procedure when
the aneurysm goes above 5 cm.
Peripheral Arterial Disease (PAD)
PAD presents with claudication (pain in the calves on exertion). The case may
also describe “smooth, shiny skin” with loss of hair and sweat glands, as well
as loss of pulses in the feet.
Spinal stenosis will give
pain that is worse with
walking downhill and less
with walking uphill or while
cycling or sitting. Pulses
and skin exam will be
normal with spinal stenosis.
Diagnostic Testing
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Best initial test: Ankle-brachial index (ABI). (A normal ABI should be ≥ 0.9.)
Blood pressure in the legs should be equal to or greater than the pressure in
the arms. If there is > 10 percent difference, then an obstruction is present.)
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Most accurate test: Angiography
Pain + Pallor + Pulseless =
Arterial occlusion
Treatment
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Best initial therapy:
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Aspirin
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Blood pressure control with ACE inhibitors
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Exercise as tolerated
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Cilostazol
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Lipid control with statins to a target LDL < 100
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Marginally effective therapy: Pentoxifylline
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Ineffective therapy: Calcium channel blocker
Acute arterial embolus
will be very sudden in
onset with loss of pulse
and a cold extremity. It is
also quite painful. AS and
atrial fibrillation are often
in the history for arterial
embolus.
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