Why can a transient ischemic attack occur in mitral stenosis?

Why can a transient ischemic attack occur in mitral stenosis?

• A. Inability of blood to move so there will be clots
• B. Embolization from carotid plaque
• C. Hyperperfusion of the brain
• D. Decreased left atrial pressure

Answer: (A)

Mitral stenosis creates a bottleneck for blood flowing from the left atrium to the left ventricle, which raises left atrial pressure and often leads to atrial dilation. This creates sluggish, stagnant blood, especially in the left atrial appendage, which promotes thrombus formation. If a thrombus breaks off, it can embolize to cerebral arteries and temporarily interrupt blood flow, producing a transient ischemic attack. The key idea is that MS predisposes to left atrial thrombi that can travel to the brain. Other options don’t fit as well because TIAs in this setting are typically due to emboli from the left atrium rather than carotid plaque (which is a different embolic source), and hyperperfusion is not a mechanism for ischemic episodes. Also, left atrial pressure is usually elevated in mitral stenosis, not decreased, so decreased LA pressure wouldn’t explain embolic risk.

Mitral stenosis creates a bottleneck for blood flowing from the left atrium to the left ventricle, which raises left atrial pressure and often leads to atrial dilation. This creates sluggish, stagnant blood, especially in the left atrial appendage, which promotes thrombus formation. If a thrombus breaks off, it can embolize to cerebral arteries and temporarily interrupt blood flow, producing a transient ischemic attack. The key idea is that MS predisposes to left atrial thrombi that can travel to the brain.

Other options don’t fit as well because TIAs in this setting are typically due to emboli from the left atrium rather than carotid plaque (which is a different embolic source), and hyperperfusion is not a mechanism for ischemic episodes. Also, left atrial pressure is usually elevated in mitral stenosis, not decreased, so decreased LA pressure wouldn’t explain embolic risk.