What is the term for a clot that occurs in an unbroken vessel and can result in a heart attack?

The term for a clot that forms in an unbroken vessel is "thrombus." A thrombus is a solid mass composed of platelets, red blood cells, and fibrin that obstructs blood flow within the vascular system. When it forms in a coronary artery, it can restrict blood flow to heart tissue, potentially leading to a heart attack. This is particularly dangerous because a thrombus can result from conditions such as atherosclerosis, where the blood vessel walls become thickened and narrowed.

In contrast, an embolism refers to a clot that has traveled from another location and is lodged in a vessel, a hemorrhage is the loss of blood from a broken vessel, and an aneurysm is a dilation of a blood vessel wall that can lead to rupture. All these terms relate to different pathophysiological processes in the vascular system, underscoring the unique role of a thrombus in the context of heart attacks.