DVT and PE: Coagulation Modifiers

• Deep Vein Thrombosis (DVT) and Pulmonary Embolus (PE) involve coagulation modifier drugs

Deep Vein Thrombosis (DVT)

• Formation of a thrombus associated with vein inflammation
• With Superficial Vein Thrombosis the thrombus occurs in a superficial vein in the extremities associated with PICC lines
• With Deep Vein Thrombosis the thrombus occurs in a deep vein - usually in the iliac or femoral veins
• In Venous thromboembolism the deep vein thrombosis detaches and moves to the pulmonary artery causing a pulmonary embolus

Etiology of DVT (Virchow's Triad)

• Venous stasis occurs when valves are dysfunctional, muscles in extremities are inactive because of obesity, pregnancy, post operative immobilization
• The endothelium is damaged directly from fractures, surgery, and trauma or indirectly through chemotherapy and diabetes
• Hypercoagulability of the blood results from hematologic disorder like anemias, malignancies, clotting and protein deficiency which will cause cancer

Risk Factors for DVT

• Pregnancy causes vasodilation which leaves space for clotting
• Oral contraceptives and post menopausal therapy with SERMS provide estrogen
• Hormone replacement therapy
• Post Chemotherapy or hysterectomy

Pathophysiology of DVT

• Platelet aggregation and fibrin entrap RBCs, WBCs, and platelets to form a thrombus
• A thrombus enlarges as more cells adhere to it
• If thrombus detaches it can cause an Emboli and possible Pulmonary embolus

DVT Clinical Manifestations

• Unilateral leg edema
• Extremity pain
• Fullness in calf/thigh
• Erythema and warmth
• Positive Homan's sign which is pain with dorsiflexion of the foot

DVT Complications

• One complication is Pulmonary Embolus which affects CO2 and O2 perfusion
• Pulmonary Embolus occurs from the blockage of the pulmonary arteries by thrombus
• Emboli are mobile clots that do not stop until they have lodged in the narrow part of the circulatory system
• Mortality rate is 30%
• Other causes of DVT are atrial fibrillation and upper extremity DVT

PE Clinical Manifestations

• Dyspnea
• Chest pain
• Hemoptysis
• Cough
• Pleuritic chest pain
• Crackles on auscultation of lungs

Hemostasis

• General term encompassing any process that stops bleeding or ability to clot
• Coagulation is hemostasis that occurs due to physiologic clotting of blood
• There is a complex relationship between substances that promote clot formation, and either inhibit coagulation or dissolve a formed clot

Coagulation System

• It is a cascade in which each activated factor serves as a catalyst that amplifies the next reaction
• The result is fibrin which is a clot forming substance
• There are Intrinsic and Extrinsic pathways

Coagulation Modifier Drugs

• Anticoagulants that are administered orally or parentally will inhibit the action or formation of clotting factors and prevent clot formation
• Antiplatelet drugs will interfere with platelet function, inhibit platelet aggregation, and prevent platelet plugs
• Thrombolytic/Fibrinolytic drugs will lyse and break down existing clots
• There are direct thrombin inhibitors and direct inhibitors of factor XA

Parenteral Anticoagulants (Heparin)

• Heparin prevents clotting by activating antithrombin, inhibits thrombin, and works on different points of the clotting cascade
• Used Prophylactically to prevent clot formation such as thrombus and embolus (dislodged clot)
• Used in emergency conditions requiring prompt therapy for stroke, DVT, PE, and disseminated intravascular coagulation in some cases
• Can also used in the prevention of stroke, MI, DVT, and PE
• Adverse reactions are hemorrhage, heparin induced thrombocytopenia, hypersensitivity reactions, and toxicity
• Given through SQ and IV infusion

Parenteral Anticoagulants (Heparin) - Nursing Administration

• For Intravenous Heparin obtain baseline vitals and labs like CBC, PLT, and HCT
• Obtain APTT every 4-6 hours until stable levels are reached for intravenous heparin treatment
• Target APTT is 1.5-2.5X normal value
• IV Heparin to be administered through infusion pump ONLY
• Given Protamine Sulfate as an antidote
• For Subcutaneous Heparin administer with a 25-28 gauge needle 1/2-5/8 inches
• Given in the abdomen at least 2 inches away from the umbilicus and rotate injection sites
• Do not aspirate
• Apply gentle pressure to the injection site for 1-2 minutes

Parenteral Anticoagulants: enoxaparin (Lovenox) LMWH (Low Molecular Weight Heparin)

• Lovenox Acts primarily on coagulation factor Xa, limiting the generation of thrombin needed for production of fibrin
• Uses: To prevent DVT in post-op patients, prevent complications in certain types of MI, and treat DVT/PE.
• Administered through SQ injection only
• Adverse Effects: Hemorrhage, neurological damage from hematoma formation in those who are receiving spinal or epidural anesthesia, and thrombocytopenia
• Nursing Administration: Do not expel air bubble, Inject in abdomen without aspiration and rotate injection sites
• Administer Protamine Sulfate as its antidote.

Oral Anticoagulants: Warfarin Sodium (Coumadin)

• Warfarin mechanism of action antagonizes Vitamin K preventing the synthesis of additional coagulation factors
• Uses incude treatment of DVT & Prevention of clots in those with AFIB, and prosthetic valves
• Prevention of Transient Ischemic Attacks (TIA), PE and DVT
• Taken orally only
• Monitored by prothrombin time (PT) and international normalized ration( INR) (PT-INR)
• Administer Vitamin K as its antidote.
• Long term outpatient therapy, therapy can be variable
  • Example: Mon, Wed, Fri, Sun with 5mg by mouth daily but Tues, Thurs, Sat with 2.5mg by mouth daily

Warfarin Sodium: Nursing Implications

• To be started while the patient is still on heparin until PT-INR levels indicate adequate anticoagulation since Heparin is a short acting anticoagulant
• A full therapeutic effect can take several days
• Monitor PT-INR regularly - keep follow-up appointments
• Therapeutic PT-INR = 2-3x's normal value
• Avoid Many herbal products which have potential interactions for increased bleeding as well as Capsicum pepper, garlic, ginger, ginkgo, St. John's wort, and feverfew

Direct Thrombin Inhibitors: dabigatran (Pradaxa)

• Works directly by inhibiting thrombin, preventing a thrombus from developing
• Used to to prevent stroke or embolism in patients who have afib not caused by valvular heart disease for those with no lab draws
• Administered orally, should not be crushed, can be taken with or without food, discontinue other anticoagulants when starting dabigatran
• Adverse effects: Bleeding, Gl discomfort

Direct inhibitor of Factor XA (rivaroxaban (Xarelto)

• Has an Anticoagulation mechanism of action by inhibiting factor Xa
• Used to prevent DVT and PE in clients who are undergoing total hip or knee/arthroplasty
• Tablets administered orally once a day with or without food at the same time every day
• Monitor Hgb, HCT, and liver and kidney function during treatment
• Adverse effects: Bleeding and elevated liver enzymes

Anticoagulants: Patient Education

Education should include:

• Importance of regular lab testing
• Signs of abnormal bleeding
• Measures to prevent bruising, bleeding, or tissue injury
• Wearing a medical alert bracelet
• Avoiding foods high in vitamin K (tomatoes, dark leafy green vegetables)
• Consulting physician before taking other meds or over-the-counter products, including herbals

Antiplatelet Drugs

• Prevent platelet adhesion
• Reduce risk of fatal and nonfatal strokes
• Treat acute unstable angina and MI
• May cause bleeding
• Aspirin is Cardio-protective and can be administered through PO and suppository with a dose of 81mg or 325mg
• clopidogrel (Plavix) used to treat stents and is taken 75mg PO daily for life long after stents
• Antiplatelet/glycoprotein inhibitors such as eptifibatide (Integrilin) are usually administered in ICU or Cardiac Cath lab, and can result to bleeding, hypotension and bradycardia

Thrombolytic Drugs/Fibrinolytics

• Drugs that break down or lyse pre-formed clots AKA: "Clot busters" Indications:
  • DVT and Pulmonary embolus
  • Occlusion of shunts or catheters
  • Treatment of Acute MI & Ischemic Stroke which has to be initiated within 6 hours of onset of symptoms for MI and 3 hours of onset for IS
• Examples: given IV to affect all blood clots in body
• anistreplase (Eminase)
• alteplase (t-PA, Activase)
• reteplase (Retavase)
• tenecteplase (TNKase)

Thrombolytic Drugs/Fibrinolytics: Mechanism of Action

• Activate the fibrinolytic system to break down the clot in the blood vessel quickly
• Activate plasminogen and convert it to plasmin, which can digest fibrin
• Reestablish blood flow to the area of the body such as the lungs via the pulmonary artery and the heart muscle via coronary arteries
• Can cause bleeding which can be internal like Intracranial alteration of the level of consciousness or superficial which leads to hypotension due to bleeding as well as anaphylactic reactions and Cardiac dysrhythmias

Thrombolytic Drugs Nursing Implications

• Follow strict manufacturer's guidelines for preparation and administration
• Monitor IV sites for bleeding, redness, pain
• Monitor for bleeding from gums, mucous membranes, nose, injection sites
• Recognize Observe for signs of internal bleeding such as decreased BP, restlessness, increased pulse
• Observe for changes in mental status

Coagulation Modifier Drugs Nursing Implications

• Monitor for therapeutic effects and blood draws
• Monitor for signs of excessive bleeding
  • Bleeding of gums while brushing teeth and unexplained nosebleeds
  • Heavier menstrual bleeding
  • Bloody or dark, tarry stools as well as bloody urine or sputum
  • Abdominal pain or vomiting blood