Pulmonary Embolism

Pulmonary Embolism

• A common, serious, and potentially fatal complication of thrombus formation within the deep venous circulation

• It can happen silently

• Can be symptomatic in the LE because of the DVT but the danger PE brings is really grave, you think the danger is in the LE but it is actually in the heart and the lungs

• An embolism is a clot that is formed elsewhere and travels to the heart and the lungs, and obstructs the pulmonary vasculature that’s going to cause all the symptoms; usually comes from DVT

Deep Venous Thrombosis

• The process of thrombosis is blood clotting

• Usually forms in LE in the venous system (in the deep veins not the superficial veins)

• There is a deep venous and superficial venous system (varicosities you see in legs)

• Can’t really see the deep venous system but can be felt if involved

When we talk about DVT proceeding into Pulmonary Embolism, we only think of one disease process:

Venothromboembolism

Which occurs more often: DVT or PE?

• DVT occurs about 3 times more often than PE

• Not all patients with DVT will go through PE

• There is a big chance; of 3 DVTs, 1 will only progress to PE

• That is why, we should be aggressive in identifying and managing patients with PE

PE can be fatal or can cause chronic ___________

thromboembolic pulmonary hypertension

• Elevation of BP in the pulmonary arteries

• If not controlled and the BP in the pulmonary arteries continues to go higher, it will lead to the development of (R) sided heart failure in the end. That is because of the thromboembolism since the thrombus may just gather up in the pulmonary arteries, that might be causing injuries to the pulmonary artery which may negatively affect the pressures inside the artery.

DVT: Post-Phlebitic Syndrome

• Inflammatory process

• Major adverse outcome of DVT alone, without PE

• Occurs in more than half of patients with DVT

• Valve incompetence and exudation of interstitial fluid

• Chronic ankle swelling and calf swelling and aching (especially after prolonged standing), skin ulceration

• Usually occurs at the end of the day; severity of the edema depends on the severity of valve insufficiency

DVT: Post Phlebitic Syndrome caused by ____________

permanent damage to the venous valves of the leg

• Cannot prevent blood regurgitation

• Due to inflammation, the valve will not function properly (valve incompetence)

Epidemiology

• Afflict millions of individuals worldwide

• Account for hundred thousand deaths annually in the US

• 15% mortality rate, exceeds mortality rate of AM

• Between heart attacks and PE, death rate is higher in PE

• Still remain difficult to detect; happens instantly, leaving no time to investigate

• Death rate from PE increases with age

• Higher in African-american than in whites

• Men = women

• ≈50% are idiopathic

Pulmonary Embolism: Pulmonary Infarction

• Pleuritic chest pain that may be unremitting or may wax and wane

• Clot from the legs will dislodge, passes through the pulmonary artery and end up in the pulmonary system, causing obstruction → infarction in the lungs and presenting as a painful event (called pain pleurisy or pleuritic chest pain)

• Painful near the pleura, making it more painful d/t presence of receptors

• Hemoptysis - d/t infarction which injured and killed the pulmonary parenchyma

Pulmonary Infarction: tissue infarction occurs ___ after embolism / obstruction

3-7 days

Pulmonary Infarction presents with:

• fever

• leukocytosis - predominance of WBCs

• elevated ESR - sign of inflammation

• Radiologic evidence of infarction

Pulmonary Infarction syndrome

• Caused by a tiny peripheral pulmonary embolism

• Pleuritic chest pain, often not responsive to narcotics

  • Lancinating pain which isn’t resolved by analgesics

• Low-grade fever

• Pleural rub

  • Parang nagkikiskisan yung pleura because it is inflammatory

• Occasional scant hemoptysis

  • Not in large amounts

  • Small as it is mostly in the periphery

• Leukocytosis

  • Predominance of neutrophil or WBC

5 most common co-morbidities in PE

1. Hypertension

2. Surgery within 3 months

3. Immobility within 30 days

4. Cancer

5. Obesity

Incidence in Air travel

• Higher altitudes = higher propensity to develop DVT

• Passengers are advised to move around, stretching and pumping the legs every 2 hours

Virchow’s Triad

• Circulatory stasis

  • Blood circulation slows down especially in conditions which require prolonged immobilization

• Endothelial Injury

  • Always starts with endothelial injury so if the endothelium is injured → trigger for blood to clot.

  • Even if the endothelium is not injured (inflammatory stage), it can still bring about thrombosis.

• Hypercoagulable State

  • obese, diabetic, HTN cancer

  • blood is thicker → higher tendency to adhere to each other

DVT Formation - Deep Veins

• pass through the deep tissues of the leg

• transport blood from the legs and feet back up to the heart

• run between muscles of the leg

• Contractions of these muscles while we move our leg and ankle help to squeeze the blood back up toward the heart

How embolus produces effects based on ocation

• If it largely affects the alveolar sacs, good exchange of O2 & CO2 would be affected.

• Capillary area - where O2 & CO2 exchange takes place

• Smaller and fewer obstructed arteries → not too much hypoxemia; can still survive otherwise if several → significant hypoxemia since majority of the lung parenchyma is involved

• Small embolus (smaller portion of the lung parenchyma involved) → more pain rather than dyspnea

When a pulmonary embolus blocks the ® ventricle, there is a sudden increase in pressure in the pulmonary artery. As a result the ® ventricle has to work harder to keep pumping blood; after a certain threshold it fails which disrupts blood flow to vital organs leading to death AKA _______

Hemodynamic Collapse

Pulmonary Embolism - Risk Factors

• Old age

• Pneumonia

• Surgery

• Fractures

• Immobility

• Diseases of the coagulation cascade

• Sickle cell disease

• COPD

Pulmonary Embolism - Treatments

• Direct Oral Anticoagulants

• Vitamin K antagonist

• Low Molecular Weight Heparin

• Reperfusion Therapy

Classic Dichotomy in PE Pathogenesis

• Inherited/ primary - unusual

• Acquired/secondary - common d/t certain medical conditions or lifestyle

Major Acquired Risk Factors for VTE

• Advancing age

• Arterial disease including carotid and coronary disease

• Obesity

• Cigarette smoking

• Chronic obstructive pulmonary disease

• Personal or family hx of venous thromboembolism

• Recent surgery, trauma, or immobility including stroke

• Acute infection

  • may promote inflammation in the blood vessels

• Long-haul air travel

• Cancer

• Pregnancy, oral contraceptive pills, or hormone replacement therapy (estrogen, testosterone

• Pacemaker, implantable cardiac defibrillator leads, or indwelling central venous catheters

Major Thrombophilias associated with venous thromboembolism - Inherited

• Factor V Leiden resulting in activated protein C resistance

• Prothrombin gene mutation 20210

• Antithrombin III deficiency

• Inherited predisposition to blood clotting

• Protein C deficiency

  • Responsible for maintaining blood in its fluid form

• Protein S deficiency

  • Protein C and S have tendency of blood to clot more in fluid

Major Thrombophilias associated with venous thromboembolism - Acquired

• Antiphospholipid antibody syndrome (APAS)

  • Similar to lupus

  • For mothers who experienced miscarriage

  • Predisposed to blood clot

• Hyperhomocysteinemia

  • High levels will signify greater likelihood of blood clotting

  • Substance in the body for homosustain

Right Ventricular Dysfunction & Ventricular Dependency

• If Pulmonary embolism greatly obstructs the pulmonary artery, expect an increase in pressure in PA

  • Increased RV afterload

  • Overtime, it gets tired getting bigger and dilates becoming dysfunctional and leading to Right ventricular sided heart failure

• Resulting in decreased o2 supply → decreased RV output → decreased systemic perfusion → decreased LV output, less ejection fraction, less cardiac output → hypotension→ systemic hypoperfusion

  • If it happens fast and pt is left unattended the pt may die instantly

Massive Acute Pulmonary embolism

Presentation	Breathlessness, syncope, and cyanosis with persistent systemic arterial hypotension; typically, >50 percent obstruction of pulmonary vasculature
Right ventricular dysfunction	Rare
Therapy	Heparin plus thrombolytic therapy or mechanical intervention

Moderate to Large / Submassive Acute Pulmonary Embolism

Presentation	Normal systemic arterial blood pressure; typically, >30 percent perfusion defect on lung scan
Right ventricular dysfunction	Present
Therapy	Heparin and NSAIDs

Small to Moderate Acute PE

Presentation	Pleuritic chest pain, hemoptysis, pleural rub, or evidence of lung consolidation; typically, small peripheral emboli
Right ventricular dysfunction	Absent
Therapy	Heparin

Pulmonary Infarction PE

Presentation	Pleuritic chest pain, hemoptysis, pleural rub, or evidence of lung consolidation; typically, small peripheral emboli
Right ventricular dysfunction	Rare
Therapy	Heparin and NSAIDs

Paradoxical PE

Presentation	Sudden systemic embolic event such as stroke
Right ventricular dysfunction	Rare
Therapy	Anticoagulation ± closure of the right-to-left cardiac shunt

Nonthrombotic PE

Presentation	Most commonly air, fat, tumor fragments, or ambiotic fluid
Right ventricular dysfunction	Rare
Therapy	Supportive

Most common symptom

Dyspnea

Most common sign; reflective of dyspnea

Tachypnea

Clinical Decision Rule

Cardinal manifestations of inflammation

• Calor - warm

• Dolor - pain

• Rubor - redness

• Tumor - swelling

• Functionless

Differential Diagnosis

Myocardial infarction	Pericarditis
Pneumonia	Intrathoracic cancer
L sided Congestive HF	Rib fracture
Cardiomyopathy	Pneumothorax
Primary pulmonary htn	Costochondritis
Asthma	Musculoskeletal pain
	Anxiety

Diagnostic - Plasma D-dimer ELISA

Advantages	Disadvantages
A normal result in this rapid turnaround blood test makes PE exceedingly unlikely.	Level is elevated in patients with many systemic illnesses that mimic PE, such as pneumonia and myocardial infarction. Level is elevated in patients with sepsis, cancer, postoperative state, and pregnancy

Diagnostics - Electrocardiogram

Advantages	Disadvantages
Universally available; may indicate ominous acute cor pulmonale or benign pericarditis	Acute cor pulmonale on electrocardiogram is not specific or PE; not a sensitive test

Diagnostics - Chest radiography

Advantages	Disadvantages
Usually, has minor abnormalities but occasionally pathognomonic; may indicate alternative diagnosis such as pneumothorax	Not specific

Diagnostics - Chest computed tomography

Advantages	Disadvantages
New-generation scanners constitute the new gold standard for diagnosis	Older generation scanners are insensitive for important but distal PE

Diagnostics - Lung scanning

Advantages	Disadvantages
High-probability scans are reliable for detecting PE; normal/near-normal scans are reliable for excluding PE	Most scans are neither high probability nor normal/near-normal; lung scans are falling out of favor; most test results are equivocal

Diagnostics - MRI

Advantages	Disadvantages
Excellent for anatomy and cardiac function; the contrast agent does not cause renal failure	In preliminary use; not widely available; experience very limited

Diagnostics - Echocardiography

Advantages	Disadvantages
Excellent for identifying right ventricular dilation and dysfunction that is not obvious clinically, thus providing an early warning of potentially adverse outcome	Not specific; many patients with PE have normal echocardiograms; the last cannot reliably differentiate causes of right ventricular dysfunction

Diagnostics - Pulmonary angiography

Advantages	Disadvantages
Necessary for catheter-based interventions	Invasive, costly, uncomfortable

Diagnostics - Venous ultrasonography

Advantages	Disadvantages
Excellent for detecting symptomatic proximal DVT; surrogate for PE	Cannot image iliac vein thrombosis; imaging of calf is operator dependent; DVT may have embolized completely, resulting in anormal finding

Diagnostics - Contrast venography

Advantages	Disadvantages
Used to be a gold standard; excellent for calf veins; necessary for catheter-based interventions	Can cause chemical phlebitis; uncomfortable; costly; may fail to diagnose massive DVT because veins are filled with thrombus and cannot be opacified

Chest radiography - Subsegmental defect

Chest radiography - Atelectasis

Chest radiography - Hampton’s Hump

Chest radiography - Westermark’s sign

Chest radiography - Melting sign of healing

Chest Computed Tomography Pictures

Lung Scanning Pictures

Venous ultrasonography pictures

Integrated Diagnostic Approach

Components of Management - Anticoagulation

• To thin out the blod

• Heparin

• Low molecular weight heparin

• Coumadin

• Newer ones include: dabigatran, apixaban, rivaroxaban

  • -aban = anticoagulant

Components of Management - Fibrinolysis

• Streptokinase

• Alteplase

Components of Management - Embolectomy

• open heart surgery to take out the blood clot from artery (great risk of death)

• If you don’t do it, the patient will die anyway

• Do it so that there’s still a chance to save the patient’s life

Components of Management - List

1. Anticoagulation

2. Fibrinolysis

3. Embolectomy

4. Vena cava filters

5. Primary Prevention

6. Secondary Prevention

Clinical predictors of increased mortality

• Systolic BP less than or equal to 100 mmHg

• Age older than 70 years

• HR higher than 100 bpm (tachycardia)

• Congestive heart failure

• Chronic lung disease (e.g. COPD, emphysema, chronic bronchitis)

• Cancer