Thrombus

A thrombus is a blood clot in a blood vessel or within the heart. A thrombus in a large blood vessel will decrease blood flow through that vessel. In a small blood vessel, blood flow may be completely cut-off resulting in death of tissue supplied by that vessel.

Some of the conditions which elevate risk of blood clots developing include heart valve replacement, a recent heart attack, extended periods of inactivity, and genetic or disease-related deficiencies in the blood's clotting abilities.