Thrombus and Embolism Flashcards
Thrombus
is a solid mass formed from the constituents of blood within the vessels or heart during life.
Virchow’s Triad-
- Changes in Vascular Wall (Endothelial damage) –
- Changes in Blood Flow (Slow or turbulent flow)
- Changes in Blood (Hypercoagulability)
INR
Meadure PT and Extrinsic pathway
Outcomes:
- Resolution – Dissolved
- Propagation – Grows
- Organisation – Fibrous Repair , scar
- Recanalisation – New channel through the occlusive thrombus = smaller capacity in new vessel
- Embolization – Breaks off and circulates.
Clinical Effects
- Occlusion of artery = ischaemia and infraction
- Embolism distant to site of thrombus
- Congestion and oedema in venous bed
- Repeated miscarriages due to Uteroplacental Vasculature = Inherited thrombophilia’s
Embolism
A solid, liquid or gas carried by blood that impacts vascular lumen.
Pulmonary emboli arise
80 % source of pulmonary = Deep veins of Thigh , popliteal vein
Saddle Emboli-
before the bifurcation of artery thus blocking both branches. Mostly in pulmonary artery.
Thromboemboli in arteries
L heart, Aneurysms and thrombi on ulcerated atherosclerosis. They go to lower body, brain, intestines , kidneys, spleen and arms.
In left heart:
- Infracts commonly left. Thrombi can then form on the affected necrotic endothelium in Ventricular Cavity. Heart beat = embolism
- Atrial Fibrillation = decreased contraction. Dilation of Left atrium. Stagnation of blood.
- Vegetations more common
Paradoxical Emboli
Form in veins but embolise to arteries. They bypass lungs by :
• Small emboli are able to pass through arterio- venous anastomoses in pulmonary circulation
• Larger by Interventricular defects in septum or a patent foramen ovale during coughing , lifting or straining. (pressure in R heart greater than left)
Stroke = more likely to have Patent Foramen Ovale.
Emboli From Atheroma
Atheroma = necrotic material from atherosclerotic plaques. Released when plaque raptures. Happen during surgery or catheterisation. Transient Ischaemic Attacks (TIAs) = episodes of neurological dysfunction appear suddenly for minutes to hours. Results of microscopic atheroemboli from carotid artery or left heart. They break up over timedue to size.
