T/F: You can get DVT in upper extremity veins?
What is seen on CXR for someone with DVT?
- Localized oligemia -> Westermark sign:
- Hampton's hump
- Consolidation (infarct)
- Usual report is "normal"
What is seen on EKG for someone with DVT?
- Right axis deviation (right sided strain)
- New onset atrial fib
What is S1Q3T3?
The classic finding; "not common, but always talked about"
What are the diagnostic tests on PE of someone with DVT?
ABG’s: increased A-a difference;
Pa02 may be above 80;
C02 usually decreased
Remember to calculate the A-a diff
- A-a difference is usually increased
- Alveolar gas equation
- [FIO2(PB-PH20) – PaC02/R] – Pa02
- [150-PaC02/0.8] - Pa02
What is the Wells Diagnostic Scoring? Considerations?
Predicts clinical likelihood of PE
- Signs/symptoms of DVT (3)
- Another diagnosis less likely than DVT (3)
- HR > 100 (1.5)
- Immobilization/surgery within 4 wks (1.5)
- Previous DVT/PE (1.5)
- Hemotpysis (1)
- Malignancy (active or treated within 6 mo) (1)
Pre test probability: ≤ 2 low; 2-6 Moderate; >6 High
What is the diagnostic approach?
- Chest CT with contrast, PE protocol
- Less commonly VQ scan
- Rarely, pulmonary angiogram
- If negative or inconclusive and clinical suspicion present….
-->further diagnostic testing
- Evaluate for DVT or perform other diagnostic test.
Pros/cons of diagnosing PE with helical/spiral CT?
- Relatively rapid
- Other diagnosis
- Advancing technology
- Not portable
- Need contrast
- Poor visualization in some areas
- Contraindication: renal insufficiency/allergy
- Reader expertise
What is a ventilation perfusion scan (VQ scan)?
- Nuclear medicine test to evaluate ventilation (V) and perfusion (Q)
- “Matched” defects
- non-diagnostic, compare to x-ray
- “Unmatched” defects
- suggestive of perfusion abnormality
Describe Pulmonary Angiogram
- Intra-arterial dye
- Directly assesses vasculature
- Rarely used now
What do each of these gross pictures show?
1- Embolus with infarct
2- Saddle embolus
How can DVT be prevented?
Based on level of risk and risk of bleeding
- Low: (under 10% VTE without prophylaxis) early ambulation only
- Moderate: (risk of VTE 40%): most general surgical pts or med pts at bedrest; give LMWH, LDUH, fondaparinux or mechanical if bleeding risk high
- High: orthopedic, major trauma, spinal cord injury; give LMWH, fondaparinux, rivoroxaban, Vit K antagonist; mechanical if bleeding risk high
How to treat PE?
- Weight-adjusted heparin IV
- Long term
- Oral factor XA inhibitors
- LMWH Thrombolysis
What is HIT?
Heparin Induced Thrombocytopenia
- Immune-mediated drug reaction
- Results in platelet removal -> thrombocytopenia (most common, 90%)
- Results in platelet aggregation and release of procoagulant microparticles (thrombosis)
- Defined by presence of heparin-reactive antibodies to platelet factor 4 (HIT Abs)
What are complications of HIT?
- Deep vein thrombosis
- Pulmonary embolism
- Myocardial infarction
- Occlusion of limb arteries (possibly resulting in amputation)
- Cerebrovascular accidents (stroke, TIA)
- Skin necrosis
- End-organ damage (e.g., adrenal, bowel, spleen, gallbladder or hepatic infarction; renal failure)
What is Warfarin?
- Antagonizes Vitamin K dependent factors (Factors 2, 7, 9, and 10 as well as protein C and protein S)
- Delayed effect based on the shortest 1/2 life (Factor 7: 6 hrs); 18-24 hrs
- Crosses placenta; CONTRAINDICATED in pregnancy
- Numerous drug-drug, drug-disease (liver), and drug-food (Vit K) interactions
- Careful monitoring of INR (standardized msmt of PT); usual targeted range is 2-3
- Reversal with Vitamin K (mild) or FFP
What things diminish Warfarin effect? INR level?
INR level will be low
- Inhibits drug absorption: Cholestyramine
- Increases metabolism (enhance p450): Barbiturates, Carbamazepine, Phenytoin, Rifampin
- Vitamin K: foods, esp leafy greens
What things enhance Warfarin effect? INR level?
INR will be high
- Displaces from albumin: choral hydrate
- Decreased metabolism (inhibits p450): Amiodarone, clopidogrel, ethanol, fluconazole, fluoxetine, metronidazole, sulfamethoxazole
- Eliminate gut bacteria and decrease K: Broad-spectrum antibiotics
What should the duration of therapy be for ?? (HIT?) (PE?)
- 3 months in patients with transient risk factors
- May be life long in patients with recurrent thrombosis or continued risk factors (e.g. malignancy, hypercoagulable state)
What is an IVC filter? What is it used to treat?
IVC filter: treatment of PE
- Patients with massive PE who could not tolerate a recurrence
- Patients with contraindications to anticoagulation
- Recommended for repeat PE despite anticoagulation or when anticoagulation is contraindicated
- Filter is a wire apparatus inserted through a catheter in the inferior vena cava to prevent PE
- Filter may be removed
What are other therapies for PE?
- Thrombolytic: reserved for patients with massive PE (clinically severe, severe cardio pulmonary compromise, i.e. hemodynamic instability, hypoxemia, RV dysfunction despite resuscitative efforts).
Summary of Pulmonary HTN
- Various causes and important to classify based on WHO grouping
- Treatment will be guided by etiology
- Progressive shortness of breath, loud P2
- Idiopathic Pulmonary Arterial HTN pathology is medial hypertrophy and intimal fibrosis
- Treatment with pulmonary vasodilators and lung transplant
Summary of DVT/PE
- Risk factors of prolonged immobility, hypercoagulable states etc.
- Symptoms of leg swelling, pain in DVT
- Sudden onset SOB+- pleuritic chest pain with hypoxemia in PE
- DVT diagnosed with venous compression ultrasonography
- PE diagnosed by spiral CT or V/Q scan
Summary of Pulmonary Vascular Disorders
- Treatment with anticoagulation (UFH, LMWH or Warfarin); Less commonly IVC filter, thrombolysis, embolectomy
- Major complications of heparin is Heparin induced thrombocytopenia
- Major complication of Warfarin is drug-drug interactions