Critical aortic stenosis limits cardiac output and can be life-threatening in patients who develop significant anemia. Oxygen delivery to tissues is inadequate. This can be seen in an elderly patient with calcific aortic valves who suffers an acute gastrointestinal bleed such as from ulcerations, diverticular bleed, or bleeding from a vascular malformation.
Unfortunately, the aortic stenosis itself may be the mechanism leading to the anemia.
The anemia may develop by two mechanisms:
- Intravascular hemolysis-dependent anemia occurs by turbulence and shear stress across a mechanical or narrowed calcified valve.
- Acquired von Willebrand syndrome. Shear stress in this case causes destruction of vWf multimers, and low-grade chronic hypoxia causes smooth muscle relaxation and reflex sympathetic vasodilation leading to ectasia of blood vessel walls. When combi