Thrombosis and Embolism

Thrombus Thrombus: a blood clot occurring in a vessel or the heart Thrombus: a blood clot occurring in a vessel or the heart A thrombus can occlude a vessel resulting in anoxic death of cells A thrombus can occlude a vessel resulting in anoxic death of cells

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Infarction: tissue that has been starved of oxygen resulting in tissue death Infarction: tissue that has been starved of oxygen resulting in tissue death What would you call heart tissue deprived of oxygen resulting in death? What would you call heart tissue deprived of oxygen resulting in death?

Myocardial Infarction (heart attack) Myocardial Infarction (heart attack) For individuals who suffer a first time heart attack, 50% are fatal For individuals who suffer a first time heart attack, 50% are fatal

Ischemia: tissue that has been starved of oxygen, but had not yet died Ischemia: tissue that has been starved of oxygen, but had not yet died It is possible to reverse ischemia with clot dissolving drugs It is possible to reverse ischemia with clot dissolving drugs Contains an enzyme that breaks down the clot Contains an enzyme that breaks down the clot

What is the difference between anoxia and infarction? What is the difference between anoxia and infarction? Anoxia is the term applied to cell death, infarction is the term applied to tissue death (many cells) Anoxia is the term applied to cell death, infarction is the term applied to tissue death (many cells)

Thrombus

Embolus Embolus: a blood clot that has ruptured or broken up and flows with the blood until it lodges or dissolves Embolus: a blood clot that has ruptured or broken up and flows with the blood until it lodges or dissolves

Thrombus and Embolus ©

Embolism/Embolus ©

How Does a Clot Form? bZUeb83uU bZUeb83uU

Steps of Thrombus Formation 1. Platelets stick together to plug the injured area. 1. Platelets stick together to plug the injured area. Platelets: solid, circulating cell fragments that are vital to stopping bleeds Platelets: solid, circulating cell fragments that are vital to stopping bleeds

Platelets

2. Clotting factors reinforce the platelets. 2. Clotting factors reinforce the platelets. Proteins found in the blood that assist with coagulation Proteins found in the blood that assist with coagulation

3. Fibrin creates a mesh over the platelets that acts as a glue. 3. Fibrin creates a mesh over the platelets that acts as a glue.

4. Other cells also stick to the platelets to reinforce the damaged area. 4. Other cells also stick to the platelets to reinforce the damaged area. Ex. Red and white blood cells Ex. Red and white blood cells

What Causes the Formation of a Thrombus? 1. Atherosclerosis

2. Vascular injury: injury to the endothelium of a blood vessel can cause a clot Why? Why?

2. Causes of Vascular Injury Injury may be caused by phlebitis Injury may be caused by phlebitis Phlebitis: inflammation of veins caused by lack of blood flow Phlebitis: inflammation of veins caused by lack of blood flow Multiple causes: chemical injury, traumatic injury, bacterial injury Multiple causes: chemical injury, traumatic injury, bacterial injury

Phlebitis

3. Blood flow: any change in blood flow bringing platelets into contact with the endothelial lining

3. Blood Flow Changes Major areas affected by blood flow that may result in a thrombus: Major areas affected by blood flow that may result in a thrombus: Plasmatic zone: Plasmatic zone: Along the tunica intima there is a layer of just plasma Along the tunica intima there is a layer of just plasma Purpose: to keep solids from hitting the lumen’s wall Purpose: to keep solids from hitting the lumen’s wall Why? Why?

Provides a buffer so rbcs, wbcs, and platelets do not hit the wall Provides a buffer so rbcs, wbcs, and platelets do not hit the wall

3. Blood Flow Changes Valves Valves Large veins can become stretched out and not function properly Large veins can become stretched out and not function properly Stretched out valves cause turbulence of blood—not good Stretched out valves cause turbulence of blood—not good

Thrombus Caused by a Valve ©

Varicose veins Varicose veins Veins have become enlarged and twisted Veins have become enlarged and twisted

Varicose Veins ©

Varicose Veins ©

4. Hypercoagulability Spontaneous blood clot Spontaneous blood clot Reason is not always known Reason is not always known

Location of Thrombi Can occur anywhere in the cardiovascular system Can occur anywhere in the cardiovascular system Mural thrombi: form in the heart Mural thrombi: form in the heart Occlusive thrombi: form in the lumen of the vessels Occlusive thrombi: form in the lumen of the vessels

Treatment of Thrombi 1. Clot dissolving drugs Break up the clot and, hopefully, prevent a myocardial infarction or stroke Break up the clot and, hopefully, prevent a myocardial infarction or stroke Without the drugs: Without the drugs: Necrosis of the thrombus occurs (after several days) Necrosis of the thrombus occurs (after several days) Tissue damage will occur Tissue damage will occur

Two of the common clot dissolving drugs: Two of the common clot dissolving drugs: Streptokinase Streptokinase tPA: tissue plasminogen activator tPA: tissue plasminogen activator These can halt the progression of ischemia These can halt the progression of ischemia

Embolism Embolism: the occlusion of a vessel by a foreign mass traveling through the blood system Embolism: the occlusion of a vessel by a foreign mass traveling through the blood system

Causes of Emboli Thrombus (main cause) Thrombus (main cause) Undissolved air or gas bubbles in the blood stream Undissolved air or gas bubbles in the blood stream Tumor fragments Tumor fragments Bone fragments Bone fragments

Origin of Emboli May arise in the veins or arteries May arise in the veins or arteries

Venous Emboli Most arise from thrombi in the legs Most arise from thrombi in the legs Called deep vein thrombosis (if forms in the deeper veins of the legs or pelvis) Called deep vein thrombosis (if forms in the deeper veins of the legs or pelvis) May cause warmth, swelling, pain near the affected vessels May cause warmth, swelling, pain near the affected vessels

Venous Emboli ©

If the thrombus travel towards the heart: If the thrombus travel towards the heart: Pass through the right side of the heart and into the lungs Pass through the right side of the heart and into the lungs Can occlude a vessel in the lungs resulting in pulmonary hemorrhage or pulmonary infarction Can occlude a vessel in the lungs resulting in pulmonary hemorrhage or pulmonary infarction

Pulmonary Embolism ©

Pulmonary Embolism ©

Animation of Embolus wtzcVbU wtzcVbU

Pulmonary Embolism Surgery (Graphic) WIMYbN8 WIMYbN8

Pulmonary Infarction Blood clot in the lungs Blood clot in the lungs When no blood reaches a section of the lung, that portion of the lung suffers an infarct, meaning it dies because no blood or oxygen is reaching it When no blood reaches a section of the lung, that portion of the lung suffers an infarct, meaning it dies because no blood or oxygen is reaching it

Arterial Emboli Usually form from thrombi in the aorta or heart Usually form from thrombi in the aorta or heart Travel away from the heart into smaller arteries Travel away from the heart into smaller arteries

Arterial Embolism ©

Lab Aorta Clear ©

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