Lecture 9 (VTE)-Exam 3 Flashcards
Pulmonary Vessels
* What is the pressure and resistance system?
- Low pressure and Low resistance system
- PVR 10x less than SVR
Venous Thromboembolism (VTE)
* What are the types?
- Pulmonary Embolism (PE)
- Deep Venous Thrombosis (DVT)
- Lower extremity deep venous thrombosis (DVT) and pulmonary embolism (PE) are two manifestations of venous thromboembolism.
DVT
* What is it?
Obstruction from a thrombus in the deep venous system, most commonly occurring in the legs
What is a distal DVT? High or low rates of PEs?
Distal DVT
* Isolated to the deep veins below the knee (aka in the calf)
* Lower rates of recurrence and pulmonary embolism
Proximal DVT
* Where is it?
* High or low chances of PE?
- Most will fall under this category
- Extends into the popliteal vein or more proximally
- More than 50% of patients with proximal vein thrombosis have a concurrent PE at presentation
Pulmonary Embolism
* Occurs in the absence of what?
* Patients often have underlying what?
* What is a common scenairo?
- Occurs in the absence of surgery or trauma
- Patients often have an underlying hypercoagulable state, although a specific thrombophilic condition may not be identified
- Common scenario is a clinically silent tendency towards thrombosis, precipitated by a stressor such as a prolonged immobilization, recent surgical procedures, oral contraceptives, pregnancy, or hormone replacement
Pulmonary Embolism
* What are the risks of VTE?
* “Secondary” pulmonary embolism among what?
- Risks of VTE among patients with medical illness, including cancer, congestive heart failure and COPD and infectious diseases like COVID-19
- “Secondary” pulmonary embolism among types of surgery patients may occur as late as a month after discharge from the hospital (they do not want to move around at home)
Pulmonary Embolism
* Why is it difficult to diagnose?
* Acute pulmonary embolism can manifest clinically as what?
* Pulmonary Embolism is a life-threatening condition resulting from what?
- Pulmonary embolism is difficult to diagnose due to its variable clinical presentation
- Acute pulmonary embolism can manifest clinically as high risk, intermediate risk, intermediate-low risk or low-risk based on severity of clinical presentation
- Pulmonary Embolism is a life-threatening condition resulting from dislodged thrombi occluding the pulmonary vasculature; right heart failure and cardiac arrest may ensue if not aggressively treated
Pulmonary Embolism
* High risk PE is life-threatening condition characterized by what?
* Many pulmonary emboli are not discovered until when?
* What is important?
- High risk PE is life-threatening condition characterized by sudden onset of chest pain/pressure, hypotension (blockage of BF), hypoxemia, and distended neck veins
- Many pulmonary emboli are not discovered until postmortem examination
- Appreciation of clinical settings that may make patients susceptible to PE and maintenance of a high degree of clinical suspicion are of paramount importance
Pulmonary Embolism
* Most common what?
* 3rd most common cause of what?
* What do 66% of hospitalizations result from?
* Who is higher risk?
* High what?
- Most common preventable cause of hospital related death
- 3rd most common cause of hospital related death
- 66% of all VTE events result from hospitalizations
- Medical>surgical pts at risk
- High morbidity/mortality
Pulmonary Embolism
* 40-50% of patients with DVT develop what? Some PE never have what?
* When does PE present after DVT? Fatal when? What are some other sxs?
* Most fatalities occur in who?
* Perfusion defects completely resolve in who?
What are the most common risk factors for VTE? (genetic and acquired?
Virchow Triad
* Major theory delineating the pathogenesis of venous thromboembolism (VTE), proposes that VTE occurs because of what?
- Alterations in blood flow, stasis
- Vascular endothelial injury
- Alterations in the constituents of the blood, inherited or acquired hypercoagulable state
Virchow Triad:
* What does endothelial injury cause? What are examples?
* What is an unprovoked DVT/PE?
* What is a Provoked DVT/PE?
Endothelial injury: endothelial cell damage promotes thrombus formation, usually at the venous valves
* Surgery
* Trauma
Unprovoked DVT/PE: no identifiable provoking event or risk factors present
Provoked DVT/PE: known risk factors and/or caused by known events
Virchow’s Triad:
What are the hypercogulability states?
Under slide: Thrombus formation is usually a result of a combination of Virchow’s triad and Inherited thrombophilia: Factor V Leiden mutation, prothrombin gene mutation, Protein C and S deficient, antithrombin deficient and antiphospholipid antibody syndrome
Virchow’s Triad
* What are the hypercoagulability (thromophilia)?
- Factor V Leiden mutation
- Prothrombin gene mutation
- Protein S deficiency
- Protein C deficiency
- Antithrombin deficiency
Virchow’s Triad
* What are some drugs that affect the virchow’s triad?
- HRT
- Testosterone
- Tamoxifen
- Steroids
- Antidepressants
SHATT
Virchow’s Triad
* What is venous statsis?
* What is the most common cause?
- Venous stasis: Poor blood flow and stasis promote the formation of thrombi
- More than 48 hours of immobility in the preceding month – 45 percent, most common
What are some other examples of venous stasis states?
- Hospital admission in the past three months – 39 percent
- Surgery in the past three months – 34 percent
- Malignancy in the past three months – 34 percent
- Infection in the past three months – 34 percent
- Current hospitalization – 26 percent
- Previous VTE
- Prolonged traveling
- Heart failure
What are the CV risk factors of VTE?
- Obesity 2.3 (95% CI 1.7-3.2)
- Hypertension 1.5 (95% CI 1.2-1.8)
- Diabetes mellitus 1.4 (95% CI 1.1-1.8)
- Smoking 1.2 (95% CI 0.95-1.5)
- Hypercholesterolemia 1.2 (95% CI 0.67-2.0)
- VTE
- CHF
⭐️⭐️⭐️⭐️
Signs and Symptoms of PE:
* Sudden what?
* Life threathening or high risk present with that?
* Should be suspected in who?
* What type of chest pain? Why?
- Sudden onset shortness of breath
- Life threatening or high-risk present with dyspnea, syncope, or cyanosis rather than chest pain
- Should be suspected in hypotensive patients with evidence of VTE and clinical findings of acute right failure – distended neck veins, tachycardia, or tachypnea
- Pleuritic chest pain (Pleuritic pain = distal emboli pulmonary infarction and pleural irritation)
Signs and Symptoms: PE
* What does it mean when pt has Isolated dyspnea of rapid onset ?
* Cough or no cough?
* What does hemoptysis iwht severe chest pain mean?
* Lungs will be what?
* Normal or low O2?
- Isolated dyspnea of rapid onset = central pulmonary embolism with hemodynamic sequala
- Cough
- Hemoptysis with severe chest pain – anatomically small PE near the periphery of the lung – leads to pulmonary infarct
- Lungs will be clear on auscultation
- Hypoxia
What are the sxs of DVT?
- Unilateral leg swelling
- Erythema
- Pain
- Positive Homan’s sign
- Calf pain upon dorsiflexion of the ankle
Diagnostic Testing of VTE
* The most important thing to do when evaluating a DVT/PE is to what?
* What is the clinical scoring system? What is the max points?
* Greatest emphasis is on presence of what?
- The most important thing to do when evaluating a DVT/PE is to risk stratify the patient (determine pre-test probability)
- Widely used clinical scoring systems is Wells index
- Maximum of 12.5 points
- Greatest emphasis is on presence of signs or symptoms of DVT and whether an alternative diagnosis is unlikely
⭐️⭐️⭐️⭐️⭐️
Electrocardiogram:
* What will be the HR?
* What is a sign present?
* What else is present?
- S1Q3T3 sign – a prominent S wave in Lead I, a Q wave in Lead III, and an inverted T wave in Lead III
- Finding is relatively specific but insensitive
- RV strain and ischemia cause the most common abnormality, T- 0wave inversion in leads V1 to V4
⭐️⭐️⭐️
What does the EKG show on a pt with PE?
Diagnostic Testing of PE
* Low risk = ≤ 4 points – likelihood of PE is less than 8%: What should you order and then what do you do if it positive or negative?
Order D-dimer
* Normal D-dimer virtually excludes a pulmonary embolism
* If the D-dimer is positive, get a CT angiogram (CT PE Protocol)
PE
* What is the best diagnostic accurary of all noninvasive imaging?
* What is the jury out on?
- CT angiogram has the best diagnostic accuracy of all noninvasive imaging
- Jury is out on VQ scan being a preferred study if the patient is pregnant
Under slide:
* Chest x-ray must be normal for the VQ scan to be properly interpreted
* If the CTA or VQ scan can’t be done (contraindicated) or if the results are indeterminate, then a lower extremity duplex US can also be ordered.
* US is also indicated if the patient is presenting with signs of DVT.
* A positive DVT with a good pretest probability = pulmonary embolism.
What do you need to do if wells score over 4 points?
likelihood of PE confirmed with testing is 41%
* Order CT angiogram
* Diagnosis confirmed by direct visualization of the thrombus in pulmonary artery; appears as a partial or complete intraluminal filling defect
What is the PERC?
*The PERC Rule is a “rule-out” tool - all variables must receive a “no” to be negative.
*The test is unidirectional: while PERC negative typically allows the clinician to avoid further testing, failing the rule doesn’t force the clinician to order tests.
Clinical Setting – Outpatient Clinics/Emergency Departments
- Where overall prevalence of PE is low, but symptoms present such as what? What criteria should you use?
- Eight factors included are what?
- If none apply, what can be excluded?
D-Dimer
* What does it measure?
* Specific or no?
* What test is highly sensitive?
* What are another things that increase d-dimer?
* Normal D-dimer virtually excludes a PE in who?
What are some inflammation, surgery, liver disease, kidney disease, vascular disorders, malignancy, therapy, pregnancy causes of increase D-dimer