THROMBOEMBOLISMsaran ak

THROMBOSIS

Formation of solid mass (thrombus) in circulation from constituents of flowing

blood.

Blood clot – in vitro | Haemostatic Plugs – simplest thrombi

ORGIN OF THROMBI

Heart | Arteries | Veins| Microcirculation

Cardiac Thrombi Arterial and Venous Thrombi Capillary Thrombi

Cardiac Thrombi : Chambers and on valve cusps. They are called vegetations seen in IE and Non Bacterial Thrombotic Endocarditis.

• Ball valve thrombi : Large round thrombus may form and obstruct the mitral valve.

Arterial thrombi ( Aneurysms, Atherosclerosis, Buerger’s Disease)Venous Thrombi ( Varicose Veins, CHF, portal hypertension)

Capillary Thrombi : Minute thrombi composed of packed RBC formed in capillaries in acute inflammatory lesions, vasculitis, DIC

Arterial T v/s Venous T

Feature Arterial Thrombi Venous Thrombi

Blood Flow Rapidly flowing Slow moving blood

Sites Aorta, Coronary, Cerebral A Sup. Varicose veins, deep leg veins

Thrombogenesis Endothelial cell injury Venous Stasis

Development Usually mural Usually occlusive

Macroscopy Grey white, Lines of Zahn Red Blue, Lines of Zahn

Microscopy LoZ- platelets, fibrin with entangled red and white blood cells

LoZ with more abundant Red Cells.

Effects Ischaemia leading to infracts

Thrombo embolism, oedema, skin ulcers

FATE OF THROMBUS

Resolution - activates fibrinolytic system> thrombus is dissolved

Organization - excluded from vascular lumen and becomes part of the

vessel wall.

Propagation - enlarge due to more deposition> cause obstruction

Thromboembolism

EMBOLISM

• The process of partial or complete obstruction of some part of the cardiovascular system by a mass carried in the circulation.

• The transported intravascular mass detached from its site of origin is called embolus.

90% - thromboemboli

THROMBOEMBOLISM

• The thrombi in early stage and infected thrombi are friable and get detached from the vessel wall.

Whole Thrombus or a part of thrombus.

• Produces ill effects at the site of their lodgment.

Arterial | Venous Thromboembolism

SOURCES Arterial Thromboembolism Venous Thromboembolism

Heart (most common) Mural thrombi (left atrium,left ven) Vegetative mural endocarditis Valvular Endocarditis Prosthetic Heart Valve Cardiomyopathy

Systemic Deep Vein Thrombosis Pelvic Veins Cavernous sinus

Lungs Pulmonary Veins

Heart Right Side of Heart

Systemic Aortic Atherosclerosis Carotid Atherosclerosis Aortic Aneurysm

Lungs Pulmonary artery

EFFECTS

• Arterial Thrombo embolism» Infarction of an organ or its affected part» Gangrene if collateral circulation is inadequate» Myocardial Infaction in coronary embolism» Sudden Death – embolism in middle cerebral artery

• Venous Thromboembolism» Obstruction of pulmonary arterial circulation>>

pulmonary thrombo embolism

PULMONARY THROMBOEMBOLISM

Most common | Most fatal

Occlusion of pulmonary arterial tree by thromboemboli.

pulmonary thrombosis - uncommon – occur in pulmonary atherosclerosis and pulmonary

hypertension

ETIOLOGY

• Thrombi originating from large veins of lower legs popliteal, femoral, iliac - 95%

• Thrombi in varicosities of superficial veins of legs and pelvic veins.

PATHOGENESIS

• Thrombi >> Detachment >> Thromboemboli that flows through venous drainage into larger veins draining into RS heart.

• Large : impacted at the main bifurcation of main pulmonary artery (saddle embolus) / right ventricle or its out flow tract.• Multiple emboli: impacted in a number of vessels,

particularly affecting the lower lobes of lung.• Paradoxical embolism: passage of embolus from R>L

through atrial septal defect .

CONSEQUENCES

• Sudden Death Massive pul. Embolism resuts in sudden death without occurrence of chest paint or dyspnoea.

• Acute cor pulmonale Numerous small emboli may obstruct pul. circulation resulting in acute right heart failure.

• Pulmonary Infarction Obstruction of small sized pul. Arterial branches

• Pul.Haemorrhage Obstruction of terminal branches

• Resolution• Pulmonary Hypertension, Chronic Cor pulmonale and chronic

pulmonary arteriosclerosis.

SYSTEMIC EMBOLISM

• Originates from thrombi in diseased heart, especially in left ventricle

• Diseases like MI, cardiomyopathy, RHD, congenital heart disease, prosthetic, cardiac valves.

• Lodgement occurs – low extremity, brain and other internal visceral organs. (spleen, kidney, intestines)

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