Clotting Disorders VTE Flashcards
What is hemostasis
Process to stop bleeding at the site of vascualr injery through complex interactions between vascular endothelium, platelets, procoagulant proteins, anticoagulant proteins and fibrinolytic proteins
What are the three key mechanisms that facilitate hemostasis
Vascular constriction, primary platelet plug formation (primary hemostasis), clot propagation through fibrin formation (secondary hemostasis)
What is the basic four step mechanism for platelet aggregation when injury occurs
Platelets first adhere to macro molecules in the sub-endothelial regions of the injured blood vessel, platelets activate, adherent platelents release substances that activate nearby platelets and recruit them, activated platelets then aggregate to form the primary hemostatic plug
What protein initiates the coagulation system when exposed due to vessel wall injury
Tissue factor
Which thrombin factor is usually seen in this coagulation, what does it do
Thrombin (factor IIa), thrombin converts fibrinogen to fibrin reinforcing the platelet aggregation and anchors it to the vessel wall
T/F:The extrinsic and intrinsic pathway both convert into the common pathway for coagulation leading to more thrombin
True
What are the natural inhibitors of the coagulation cascade
Antithrombin III, Protein C, Protein S
What is the most common defect in the natural coagulant system, what occurs
Factor V leiden, mutation in factor V that results in resitance to inactivation by protein C and protein S
What is thrombosis
Formation of an inappropriate fibrin-platelet aggregate
Where are sites thrombosis can take place
Endothelium of blood or lymphatic vessels (mural thrombus) , within the heart (cardiac thrombus), free in blood or lymphatic vessels (thromboembolus)
What is venous thromboembolism, what are two types
Clot formation within the venous circulation, DVT and pulmonary embolism
Where do most DVTs take place
The proximal veins (Deep femoral vein and superficial femoral vein)
What is the order of pulmonary embolism types from most dangerous to least dangerous
Saddle embolism, lobar embolism, segmental, subsegmental
What guide is used to assess risk for ischemic stroke, what are its parameters
CHADS2/ Congestive heart Failure, Hypertension, Age greater than 75, Diabetes, Stroke or Trans ischemic attack
T/F: On the CHADS2 score each category is worth one point
False: On the CHADS2 score each category is worth one point except Stroke or TIA, which is worth 2 points
What are the three big risk factors for VTE, what are the collectively called
Blood Stasis, Hypercoagulable State, Vascular Injury/ Virchow’s triad
What are the other risk factors for VTE
Age greater than 40 years, Surgery, Major trauma or lower-extremity injury, Cancer, Pregnancy
What medication class can increase risk of blood clots
Estrtogens
What are situations that could lead to blood stasis
Damage to venous valves, periods of proplong immobility, abnormalities of blood flow
What disease can cause a hypercoaguable state, other factors
Cancer Malignancy, female gender, being black, older age (greater than 40), pregnancy
T/F: Smoking increase risk of VTE
True
What are examples of or may cause vascular injury
Trauma, Surgery, Heart valve replacement, Artherosclerosis or Artheromatous plaque, indwelling vascular catheters
What orthopedic surgery has the highest risk for VTE
Total hip arthroplasty and Hip fracture surgery
In hospitalized medical patients what gives the most points on Padua Prediction Risk Assesment Model
Active Cancer, Previous VTE, Reduced moblility, Already known thrombophilic condition`
What are common signs and symptoms of DVT
Swelling, redness, tenderness, edema, palpable cord, post-thrombotic syndrome
What are common signs and symptoms of pulmonary embolism
Chest pain, cough with blood, tachycardia, palpations, low grade fever, patient passes out
What is used to diagnosis if patient as VTE, why is it not always reliable
D-Dimer/ elevations can occur due to recent surgeries, increasing age, pregnancy and cancer
What risk assesment scale is used to see if a DVT is present
Wells pretest/ Tenderness along entire deep vein system, Swelling of the entire leg, greater than 3 cm in calf circumference, pitting edema, collateral superficial veins, active cancer, prolonged immobility or paralysis, recent surgery
What does the Wells score need to be in order for DVT to be likely
Greater or equal to 2
What is the first choice for diagnostic imaging for PE
CT pulmonary angiography
When using the Wells score for pulmonary embolism put the criteria in order from the highest scores to lowest scores
Signs or DVT, Alternative diagnosis to PE less likely ( 3 points)/ History of PE or DVT, heart rate greater than 100 beats/min, recent surgery or immobility (1.5 points)/ Active malignancy and hemoptysis (1 point)
What must the Wells score for PE be for it to be most likely present
Greater than 4
T/F: If the D- dimer is negative PE and DVT is ruled out
True
What is post-thrombotic syndrome
Chronic venous insuffciency as a consequence of valvular incompetence and venous hypertension due to thrombotic obstruction, usually occurs following DVT
T/F: Initial VTE treatment should include a rapid-acting anticoagulant
True
What is the usual dose to start a patient on for warfarin
5 mg
What is used to monitor heparin, when is it checked
aPTT, every 6 hours
What syntheizes the major clotting factors, what are three types of factors,
Liver/ contact activation factor, vitamin K factor, thrombin-sensitive factor
