Macroangiopathic haemolytic anaemia

Macroangiopathic haemolytic anaemias are characterised by the intravascular haemolysis of RBCs due to mechanical forces in the large blood vessels, hence the name. This may cause haemolytic anaemia. The most important causes are severe aortic stenosis and prosthetic heart valves.

In severe aortic stenosis the lumen of the aortic valve is so narrow that the blood that flows through it reaches very high velocities. This rapid, turbulent transvalvular blood flow damages the RBC membrane, causing them to haemolyse. Turbulent blood flow through prosthetic heart valves causes similar damage to the RBCs.

The peripheral blood smear will show fragmented red blood cells (schistocytes).