thromboembolic disease

Question 1

Substances which Embolize

Answer 1

Air
Amniotic Fluid
Foreign Bodies
Parasitic Eggs
Septic Emboli
Tumor Cell
MOST COMMON: Thrombus

Question 2

purpose and components of hemostatic system

Answer 2

Purpose: Prevent blood loss due to vascular Injury

Components:
Formed Elements: Cells-Platelets, Monocytes, RBCs
Plasma Proteins-Clotting Factors, Fibrinolytic Factors, Inhibitors

Vessel Wall:
Epithelium
vonWillibrand Factor (vWF)
Collagen
Tissue Factor

Question 3

steps in hemostasis

Answer 3

Vascular Injury (vasoconstriction)
Primary Hemostasis-Platelet Plug
Secondary Hemostasis-Clotting Cascade: Activate Fibrin
Fibrinolysis
Regulation

Question 4

arteries vs veins

Answer 4

A:
Higher Pressure
More smooth muscle
Atherosclerosis

V: 
More Distensible
Capacitance Vessels
Valves
Virchow’s Triad

Question 5

arterial thromboembolism

Answer 5

Arterial Occlusive Disease
MI
Ischemic CVA
Mesenteric Ischemia
Vasculitides

Question 6

venous thromboembolism (VTE)

Answer 6

PE
DVT
Superior Vena Cava Obstruction
Chronic ThromboEmbolic Pulmonary HTN (CTEPH)
Dural Sinus Thrombosis
Portal Vein Thrombosis
Vasculitis-Bechet’s, 
Granulomatosis with polyangiitis
Mesenteric Vein Occlusion

Question 7

Pulmonary venous thromboembolism

Answer 7

aka Pulmonary Embolism (PE)
3rd leading cause of death among hospital pts
Often not recognized ante mortem (before death)
less than 10% of pts receive specific tx

Question 8

thrombus

Answer 8

Most common etiology of emboli
Most Common Site of Origin
Deep Veins of the Lower Extremities (i.e. popliteal, common iliac)
Found in 50-70% of pts with symptomatic PE
Can Form Anywhere!

Question 9

VTE dx

Answer 9

NOTORIOUSLY DIFICULT DIAGNOSIS
Findings depend of size of embolus and preexisting cardiopulmonary disease
Common signs and symptoms are not specific

Question 10

VTE s/s

Answer 10

Dyspnea
Pain on inspiration
Tachypnea

Others:
Cough
Hemoptysis
Leg Pain
Tachycardia
Palpitations
Crackles
Homan’s Sign (pain with dorsiflexion of foot)

Question 11

VTE ddx

Answer 11

Pneumonia
Lung Cancer
MI
COPD
Asthma
Traumatic Injury
Muscle Strain
Costochondritis
Inhalation Injury
Aortic Aneurysm
Congestive Heart Failure

Question 12

virchow’s triad

Answer 12

Stasis
Hypercoagulability
Endothelial Injury

Question 13

virchow’s triad: stasis

Answer 13

Prolonged immobility:

post orthopedic surgery,
Low Cardiac Output
Pregnancy
Post CVA
Travel (Air, Car)

Question 14

virchow’s triad: hypercoagulability

Answer 14

Medications: 
Oral Contraception, Hormone Replacement
Malignancy
Genetic: 
*Factor V Leiden*
Protein C/S/antithrombin III 
deficiency/dysfunction 
prothrombin gene mutation
hyperhomocysteinemia
antiphospolipid antibodies

Question 15

virchow’s triad: endothelial injury

Answer 15

Traumatic Injury
Recent Surgery
Previous Thrombosis

Question 16

PE clinical findings: EKG

Answer 16

Abnormal in about 70% of pts with PE

Most Common Finding: Sinus Tachycardia (most common!!) and Nonspecific SR and T wave changes

Right Heart Strain: RBBB, Right Axis Deviation, S1Q3T3

prominent S wave in 1, Q wave in 3, T wave in 3 ?

Question 17

PE clinical findings: ABG

Answer 17

Usually Respiratory Alkalosis
Abnormal pO2 and Alveolar-arterial O2 gradient
NOT DIAGNOSTIC
Profound Hypoxia with Normal Chest X-ray THINK PE

Question 18

PE lab findings: D-dimer

Answer 18

Fibrin Degradation product
Sensitivity 95-97%, Specificity 45%
NO diagnostic threshold established for positive result: may be elevated in inflammation/trauma/infection
*BEST INFORMATION WHEN NEGATIVE (SN-OUT: good at ruling out when negative)
Negative : less than 500mcg/L, Likelihood ratio 0.11-0.13

Question 19

PE other lab findings

Answer 19

Serum Troponins, BNP typically elevated in PE

Not Useful in diagnosis, correlate with adverse outcomes

Question 20

PE imaging

Answer 20

Chest Xray
Useful to rule out other etiologies: pneumonia, CHF, etc

Most Frequent findings:
Atelectasis, Parenchymal Infiltrates, Pleural Effusion

Uncommon Findings
Westermark Sign
Hampton’s Hump

Question 21

Westermark’s Sign

Answer 21

prominent central pulmonary artery with local oligemia

Absence of vascular markings distal to engorged central pulmonary Vein

Question 22

Hampton’s Hump

Answer 22

pleural based areas of increased opacity representing intraparenchymal hemorrhage

Question 23

PE clin findings: CT angiography

Answer 23

Requires IV contrast dye (don’t want to give to renal failure pts)

Primary finding suggestive of PE:

Intravascular filling defect

Very sensitive for central vascular filling defects

~80% sensitive, 96% specific
15-20% false negative rate

Question 24

CT angiography Secondary Findings suggestive of PE

Answer 24

Abrupt arterial cutoff, asymmetrical blood flow, prolonged or slowed filling

Question 25

Normal CT chest requires ??

Answer 25

initiation of empiric therapy (high pretest probability) or further testing (V/Q scan, etc.)

Question 26

CT pics

Answer 26

saddle embolus: very concerning finding

Question 27

PE clin findings: Ventilation Perfusion (V/Q) scan

Answer 27

Perfusion assessed by injection of radiolabeled albumin injected into venous circulation Ventilation assessed by records distribution of inhaled radio labeled gas The two images are compared, looking for defects Criteria for assessment are complex, confusing and not standardized

Question 28

Ventilation Perfusion (V/Q) scan reported in terms of ??

Answer 28

probability: low, intermediate, and high PIOPED1; If low, 14% probability of PE Combined with low pretest probability, lowers risk to 4% If indeterminate, low or intermediate probability, further testing required

Question 29

Venous Thrombosis Studies: Venous Ultrasonography | positive test ??

Answer 29

Incompressibility of common femoral or popliteal veins In a patient with appropriate symptoms Positive predictive value 97% Negative Test: Full compressiblity at both vessels Negative Predictive value 98% Less accurate in distal thrombi, recurrent thrombi, and asymptomatic patients

Question 30

Wells Criteria: scoring systems to assess PE Risk

Answer 30

3: Clinical Signs and symptoms of DVT: Unilateral edema, and pain with palpation 3: Alternative Diagnosis Less likely than PE 1.5: Pulse >100bpm 1: Immobilization >3days in past 4 wks 1: Previous DVT/PE 1: Hemoptysis 1: Cancer (With Tx w/in past 6 mo. or Palliation) Total >4pts: Imaging warranted Total

Question 31

PE/DVT preventable?

Answer 31

ARE preventable | Risk Assessment for Surgical Patients

Question 32

pts @ High risk for PE/DVT

Answer 32

``` Major orthopedic procedure/arthroplasty Abdominal/pelvic cancer undergoing surgery recent spinal cord injury major trauma w/in previous 90days >3 intermediate criteria ```

Question 33

pts @ Intermediate Risk for PE/DVT

Answer 33

Ambulation less than 2x/day Active Inflammation/infection/malignancy, Major Non orthopedic surgery h/o VTE, CVA Central venous access/PICC line BMI greater than 30 OCP/HRT use Immobilization more than 72hrs Hypercoagulable state nephrotic syndrome burns, cellulites', varicose veins, paresis Systolic Heart Failure COPD exacerbation

Question 34

pts @ low risk for PE/DVT

Answer 34

Minor procedures, age younger than 40 without addition risk factors Ambulatory with expected length of stay less than 24hrs

Question 35

PE/DVT interventions

Answer 35

Sequential Compression Devices (SCDs) Medication: Heparin Lovenox

Question 36

pulmonary VTE tx

Answer 36

Heparin: binds ATIII, accelerates inact of thrombin factor 10a, 9a thrombolytic therapy: Thrombolytic Therapy Streptokinase, urokinase, alteplase(tPA) Systemic or catheter directed tPA IVC filter: short term, Can increase PE risk in the first two years of therapy Must be Removed embolectomy: Rare, Reserved for critically ill patients after unsuccessful thrombolytic therapy