DVT/PE therapeutics tutorial

Question 1

what are the cardiac causes of chest pain?

Answer 1

• -STEMI/NSTEMI
• -Aortic dissection
• -cardiac tamponade
• -pericarditis

Question 2

what are the GI causes of chest pain?

Answer 2

• -GERD and erosive esophagitis
• -esophageal perforation
• -PUD
• –Acute pancreatitis
• -Mallory-Weiss syndrome

Question 3

what are the pulmonary causes of chest pain?

Answer 3

• -PE
• -tension pneumothorax
• -pneumonia
• -asthma exacerbation
• -pleura leffusion

Question 4

what are the other causes of chest pain except for cardiac, pulmonary and GI?

Answer 4

• -costochondritis
• -pannic attack
• -herpes zoster

Question 5

what is the differential diagnosis of a 2-hour history of pleuritic chest pain, dyspnoea, hemoptysis, and pleural rub?

Answer 5

Pulmonary Embolus
Pneumonia with Pleuritic Involvement
–Chronic/long-standing conditions unlikely causes of 2-hour history
1)Bronchiectasis / Chronic Bronchitis
2)Chronic infections such as TB or lung abscess
3)Lung Cancer
4)An inflammatory condition such as Sarcoidosis, Good Pasteur’s Syndrome

Question 6

what are the symptoms of PE?

Answer 6

• -Acute onset of symptoms, often triggered by a specific event (e.g., on rising in the morning, sudden physical strain/exercise)
• -Dyspnea and tachypnea (> 50% of cases)
• -Sudden chest pain (∼ 50% of cases), worse with inspiration
• -Cough and hemoptysis
• -Possibly decreased breath sounds, dullness on percussion, split-second heart sound audible in some cases
• -Tachycardia (∼ 25% of cases), hypotension
• -Jugular venous distension
• -Low-grade fever
• -Syncope and shock with circulatory collapse in massive PE (e.g., due to a saddle thrombus)
• -Symptoms of DVT: unilaterally painful leg swelling

Question 7

what are the risk factors for DVT and PE?

Answer 7

• -History of DVT or PE (30x increased risk)
• -Immobilization: e.g., post-surgery, long-distance flights, trauma (20x increased risk)
• -Age > 60 years
• -Malignancy
• -Hereditary thrombophilia (especially factor V Leiden)
• -Pregnancy, estrogen use (oral contraceptives)
• -Obesity
• -Smoking
• -IV drug use
• -Nephrotic syndrome
• -Insufficient thrombosis prophylaxis, noncompliance with prophylaxis
• -To remember the risk factors of deep vein thrombosis, think “THROMBOSIS”: Travel, Hypercoagulable/HRT, Recreational drugs, Old (> 60), Malignancy, Blood disorders, Obesity/Obstetrics, Surgery/Smoking, Immobilization, Sickness (CHF/MI, IBD, nephrotic syndrome, vasculitis)!

Question 8

name direct Factor Xa Inhibitor

Answer 8

apixaban/rivaroxaban

Question 9

name direct thrombin inhibitor

Answer 9

dabigatran

Question 10

Indirect Inhibitor of Factor Xa??

Answer 10

LMWH

Question 11

Indirect Inhibitor of both Factor Xa and Thrombin??

Answer 11

heparin

Question 12

an anticoagulant that Interferes with the synthesis of clotting factors by preventing the reduction of vitamin K?

Answer 12

warfarin

Question 13

UFH vs LMWH?

Answer 13

1) Unfractionated Heparin (UFH) – complexes with and activates anti-thrombin, and is therefore an indirect inhibitor of factor Xa and thrombin – monitored by APTT.
2) Low molecular weight heparin (LMWH) eg enoxaparin – complexes with and activates anti-thrombin, and is therefore an indirect inhibitor of factor Xa – Laboratory monitoring usually not indicated.

Question 14

does LMWH require monitoring of PTT?

Answer 14

no

Question 15

how warfarin is monitored?

Answer 15

by INR

Question 16

do dabigatran and rivaroxaban require lab monitoring?

Answer 16

No

• -Dabigatran – direct thrombin inhibitor (binds thrombin and prevents the cleavage of fibrinogen to fibrin). Laboratory monitoring not indicated.
• -Rivaroxaban and Apixaban – reversible direct inhibitors of factor Xa. Laboratory monitoring not indicated.

Question 17

what anticoagulants can be used in hemodynamically stable patients with PE?

Answer 17

1)Subcutaneous Low Molecular Weight Heparin
–eg Enoxaparin 1 mg/kg subcut twice daily.
(Unfractionated heparin (UFH) in patients with renal failure and those who may still require thrombolysis)
2)New Factor Xa Inhibitors have been shown to be equally effective, to result in less major bleeding events, and no need to monitor the anticoagulant effect
–Apixaban
–Rivaroxaban

Question 18

in a patient with PE and the hypoxia and hypotension, what are the management options?

Answer 18

1) The patient should be admitted to the Intensive Care Unit (ICU)
2) Active resuscitation with oxygen should be commenced immediately.
3) Intravenous fluid and possibly inotropic agents (vasopressors such as norepinephrine, dopamine or dobutamine) should be commenced immediately.
4) Given the presence of hypotension (SBP <90mmHg) systemically administrated thrombolytic therapy is indicated (Intravenous tPA) followed by intravenous unfractionated heparin (IV UFH).
5) Initial intravenous heparin bolus: 80 units/kg.
6) Continuous intravenous heparin infusion: 18 units/kg/hour
7) If no improvement gained surgical or catheter embolectomy could be considered.

Question 19

what are the indications for thrombolytic therapy?

Answer 19

n cases of massive PE causing right heart failure

In hemodynamically unstable patients requiring resuscitation

Question 20

What investigation(s) should be performed so as to confirm the diagnosis of pulmonary emboli?

Answer 20

• -Spiral (Helical) CT scanning with intravenous contrast [CT pulmonary angiography (CTPA)]
• -Ventilation Perfusion Scan
• -Pulmonary angiography (with intra-arterial contrast)
• -Are all possible confirmatory investigations

Question 21

what are the indications of ventilation/perfusion scans?

Answer 21

–Indication: alternative to CT angiography in patients with severe renal insufficiency or contrast allergy
–Method: detects areas of ventilation/perfusion (V/Q) mismatch via perfusion and ventilation scintigraphy
Assessment
–Perfusion failure in normally ventilated affected pulmonary area (mismatch) suggests PE
–Evidence of normal lung perfusion rules out PE → ventilation scintigraphy superfluous

Question 22

what is the indication of pulmonary angiography?

Answer 22

• -Indications: only conducted if CT angiography unavailable
• -Procedure: right heart catheterization → insertion of a catheter into a pulmonary artery → radiograph after administration of contrast agent

Question 23

what is the best test for PE?

Answer 23

• -Helical spiral CT/CT pulmonary angiography (CTPA): best definitive diagnostic test
• -Contrast-enhanced imaging of the pulmonary arteries
• -High sensitivity, specificity and immediate evidence of pulmonary arterial obstruction
• -Visible intraluminal filling defects of pulmonary arteries
• -Wedge-shaped infarction with pleural effusion is almost pathognomonic for PE

Question 24

what meds are used for long-term anticoagulation and prophylaxis of PE?

Answer 24

• -Oral anticoagulant therapy should be commenced once the diagnosis of pulmonary embolus is confirmed.
• -Warfarin was most commonly prescribed.
• -Recent trial data suggest that Dabigatran, Apixaban, and Rivaroxaban;
  1) Provide very similar protection against recurrent thrombosis,
  2) Causes less bleeding,
  3) Need less/no monitoring,
  4) Monoclonal antibody binders acting as reversal agents now available
• -Patients with a hypercoagulable state with DVT or PE: heparin followed by 3–6 months of warfarin for the first event, 6–12 months for the second, and lifelong anticoagulation for further events

Question 25

how much long-term anticoagulation should be continued?

Answer 25

• -Typically anticoagulation continued for at least 3 months for a first episode of pulmonary embolus in a patient with identifiable reversible or temporary risk factors (as in this woman).
• -Patients with a hypercoagulable state with DVT or PE: heparin followed by 3–6 months of warfarin for the first event, 6–12 months for the second, and lifelong anticoagulation for further events

Question 26

what are the irreversible risk factors of PE?

Answer 26

• -Antithrombin III deficiency,
• -Protein C deficiency,
• -Protein S deficiency,
• -Factor V Leiden gene mutation,
• -Prothrombin 20210 gene mutation,
• -Homocysteinemia,
• -High factor VIII levels
• -Antiphospholipid antibodies

Question 27

how much anticoagulation should be continued in patients with irreversible risk factors?

Answer 27

• -Anticoagulation therapy recommended for 6 - 12 months for patients with PE and any irreversible risk factors.
• -Anticoagulation recommended for at least 12 months (and possibly indefinitely) for patients with PE and either antiphospholipid antibodies or > 2 irreversible risk factors.
• -Check D-dimers one month post discontinuation of anticoagulation therapy.