When physicians diagnose arterial blockages, they quote the reduction in flow rate. The flow rate in an artery has been reduced to of its normal value by a blood clot and the average pressure difference between the ends of the artery has increased by . By what factor has the clot reduced the radius of the artery?
Plaque deposits reduce a blood vessel’s radius to of its original value. The action of the heart compensates for the decrease by increasing the pressure difference along the vessel to keep the flow rate constant. By what factor must the pressure difference increase?