What is the pathophysiology of severe aortic stenosis (AS)?

Updated: May 07, 2019
  • Author: Xiushui (Mike) Ren, MD; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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In patients with severe aortic stenosis, atrial contraction plays a particularly important role in diastolic filling of the LV. Thus, development of atrial fibrillation in aortic stenosis often leads to heart failure due to an inability to maintain cardiac output.

Increased LV mass, increased LV systolic pressure, and prolongation of the systolic ejection phase all elevate the myocardial oxygen requirement, especially in the subendocardial region. Although coronary blood flow may be normal when corrected for LV mass, coronary flow reserve is often reduced.

Myocardial perfusion is thus compromised by the relative decline in myocardial capillary density and by a reduced diastolic transmyocardial (coronary) perfusion gradient due to elevated LV diastolic pressure. Therefore, the subendocardium is susceptible to underperfusion, which results in myocardial ischemia.

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