what is the pathophysiology of pulmonary embolism

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How does a pulmonary embolism kill you?

This blockage can cause serious problems, like damage to your lungs and low oxygen levels in your blood. The lack of oxygen can harm other organs in your body, too. If the clot is big or the artery is clogged by many smaller clots, a pulmonary embolism can be fatal. Pulmonary embolisms usually travel to the lungs from a deep vein in the legs.

Who is likely to have a pulmonary embolism?

Who is at risk of developing a pulmonary embolism (PE)? People at risk for PE are those who: Have been inactive or immobile for long periods of time. Have certain inherited conditions, such as blood clotting disorders or factor V Leiden. Are having surgery or have broken a bone (the risk is higher weeks following a surgery or injury). Have cancer, a history of cancer, or are receiving chemotherapy. Other risk factors for PE are: Being overweight or obese. Smoking cigarettes.

Is pulmonary embolism a deadly disease?

Pulmonary embolism remains a common and potentially deadly disease, despite advances in diagnostic imaging, treatment and prevention. Managing pulmonary embolism requires a multifactorial approach involving risk stratification, determining appropriate diagnostics and selecting individualised therapy.

What are the signs of a pulmonary embolism?

• Responses to sudden, sharp pains in the chest, especially during inhalation. This pain is called pleuritic chest pain.
• Seizures
• Blue-tinged skin is an indication that oxygen deprivation is occurring. ...
• Individuals who experience recurring (small) pulmonary emboli may also display swollen ankles or legs, and experience generalized weakness.

What is the pathophysiology of thromboembolism?

Thrombus formation and propagation depend on the presence of abnormalities of blood flow, blood vessel wall, and blood clotting components, known collectively as Virchow's triad. Abnormalities of blood flow or venous stasis normally occur after prolonged immobility or confinement to bed.

What happens to the body during a pulmonary embolism?

Pulmonary embolism (PE) occurs when a blood clot gets stuck in an artery in the lung, blocking blood flow to part of the lung. Blood clots most often start in the legs and travel up through the right side of the heart and into the lungs.

What is pulmonary embolism in simple terms?

(PUL-muh-NAYR-ee EM-boh-lih-zum) A sudden blockage of an artery (blood vessel) in the lung. A pulmonary embolism usually occurs when a blood clot in a deep vein in the leg or pelvis breaks loose and travels through the blood to the lungs.

What is the pathogenesis of the hypoxemia in pulmonary embolism?

PULMONARY EMBOLISM The main mechanisms of hypoxemia in PE are V/Q mismatch and low level of mixed venous blood oxygen (PvO2). [49] V/Q mismatch occurs due to redistribution of blood from occluded pulmonary arteries to the nonoccluded vessels.

How does a PE affect the heart?

Pulmonary hypertension That's another term for high blood pressure in the arteries in your lungs. A PE also causes pressure in the right side of your heart to increase. This means your heart's right side works harder than it should. Over time, the result is heart failure, a weakening of the heart's pumping ability.

What are 3 signs and symptoms associated with a pulmonary embolism?

What are the symptoms of pulmonary embolism?Sudden shortness of breath — whether you've been active or at rest.Unexplained sharp pain in your chest, arm, shoulder, neck or jaw. ... Cough with or without bloody sputum (mucus).Pale, clammy or bluish-colored skin.Rapid heartbeat (pulse).Excessive sweating.More items...•

What increases risk of pulmonary embolism?

People at risk for PE are those who: Have been inactive or immobile for long periods of time. Have certain inherited conditions, such as blood clotting disorders or factor V Leiden. Are having surgery or have broken a bone (the risk is higher weeks following a surgery or injury).

What are the different types of pulmonary embolism?

There are three types of PE: acute, subacute, and chronic. Below is a deeper look into each of these types....The most common symptoms can include:progressive dyspnea.pleuritic chest pain.coughing up blood.

Are there stages of pulmonary embolism?

A new rule classifies patients who have pulmonary embolism into five disease stages that reveal an increasing risk of death or other adverse outcome.

Why is CO2 low in pulmonary embolism?

End-tidal carbon dioxide tension (PET,CO2) is a physiological surrogate for vascular obstruction from PE. Pulmonary thromboembolism results in dead space ventilation and, therefore, prevents meaningful gas exchange in the subtended lung unit, yielding an alveolar CO2 content as low as 0 mmHg.

Is there hypoxia in pulmonary embolism?

Most patients with severe, acute pulmonary embolism (PE) have arterial hypoxemia.

What causes hypotension in pulmonary embolism?

The systemic hypotensive reaction to pulmonary embolism is only in part due to a decreased cardiac output. The more severe responses are best explained on the basis of a vasomotor reflex producing a decrease in systemic arterial resistance.

What are the odds of surviving a pulmonary embolism?

However, reported survival after venous thromboembolism varies widely, with "short-term" survival ranging from 95% to 97% for deep vein thrombosis8,9 and from 77% to 94% for pulmonary embolism,4,6,8,9 while "long-term" survival ranges from 61% to 75% for both deep vein thrombosis and pulmonary embolism.

Are there stages of pulmonary embolism?

A new rule classifies patients who have pulmonary embolism into five disease stages that reveal an increasing risk of death or other adverse outcome.

How long can you live with a pulmonary embolism?

Recent findings: The death rate after pulmonary embolism is less than 5% during 3-6 months of anticoagulant treatment, provided that the patient is hemodynamically stable and free of major underlying disease. The rate of recurrent thromboembolism is less than 5% on anticoagulant therapy, reaching 30% after 10 years.

How long does it take for a pulmonary embolism to dissolve?

A DVT or pulmonary embolism can take weeks or months to totally dissolve. Even a surface clot, which is a very minor issue, can take weeks to go away. If you have a DVT or pulmonary embolism, you typically get more and more relief as the clot gets smaller.

What is a PE in a pulmonary system?

Pulmonary embolism (PE) and deep venous thrombosis (DVT) exist on the spectrum of venous thromboembolic disease (VTE). PE results when thrombus migrates from the venous circulation to the pulmonary vasculature and lodges in the pulmonary arterial system. The clinical presentation of acute PE ranges from asymptomatic and incidentally discovered to massive PE causing immediate death. This review focuses on the epidemiology, risk factors, pathophysiology, and natural history of PE.

What is post PE syndrome?

8384Persistent thrombus can contribute to ongoing increased PVR and RV pressure load and have physiologic consequences leading to functional impairment and decreased quality of life. The “post-PE syndrome” is defined by dyspnea, exercise intolerance, and diminished quality of life in the setting of suboptimal cardiac function, pulmonary artery flow dynamics, or pulmonary gas exchange. 85The most severe manifestation of post-PE syndrome is chronic thromboembolic pulmonary hypertension (CTEPH), which affects an estimated 1 to 5% of survivors of acute PE. 8687Chronic thromboembolic disease (CTED) refers to persistent perfusion defects without pulmonary hypertension, and it is estimated that based on the incidence of acute PE in the United States, 35,000 people will have CTED and 1,250 will have CTEPH. 8588

How many cases of venous thromboembolism are there in the US?

Venous thromboembolism is a major worldwide burden of disease with ∼10 million cases per year and an associated substantial morbidity and mortality. 1The true incidence of PE is unknown, but in the United States, it is estimated that nearly a third of hospitalized patients are at risk of developing VTE and up to 600,000 cases of VTE are diagnosed per year with 100,000 deaths related to these diseases. 23In the United States, the estimated incidence of diagnosed VTE is 117 per 100,000, but the true incidence is likely to be more as these diseases are frequently undiagnosed or diagnosed only at autopsy. 456Based on a review of national inpatient data, the number of admissions for PE increased from nearly 60,000 in 1993 (23 per 100,000) to more than 202,000 in 2012 (65 per 100,000). 7Despite the increased incidence of PE, there was a decreased incidence of massive PE and hospital mortality over the same time period. Comorbidities associated with PE are also increasing (aging population and medical comorbidities), but the increased incidence in the face of decreased mortality likely reflects increased use of more sensitive CT angiography for diagnosis rather than a true change in prevalence. 78910

What are the genetic factors that increase the risk of VTE?

There are several genetic conditions known to increase the risk of VTE including factor V Leiden, prothrombin gene mutation ({"type":"entrez-nucleotide","attrs":{"text":"G20210","term_id":"1254909","term_text":"G20210"}}G20210-A), antithrombin deficiency, protein C deficiency, and protein S deficiency. Deficiencies in protein C, protein S, and antithrombin are relatively infrequent but potent, and they can confer a 5- to 10-fold increase in venous thrombosis in those affected. 171819Factor V Leiden is a more common mutation leading to hypercoagulability, and it is associated with a 5-fold increased risk of VTE with heterozygotes and a 10-fold risk with homozygotes. 20Finally, the prothrombin gene mutation can be detected in 7% of patients with VTE and increases the risk of thrombosis threefold. 21

How much does estrogen affect VTE?

The risk of VTE while on estrogen containing oral contraceptives increases three- to fourfold. 41The risk is highest in the first year of use (especially the first 3 months), but it does not increase thereafter and is eliminated with cessation of therapy. 42A similar increase in risk occurs with postmenopausal hormone replacement therapy. 43

What are the consequences of PE?

PE contributes to gas exchange abnormalities and hypoxemia, but it is predominantly the hemodynamic consequences of PE that are responsible for increased morbidity and mortality. An understanding of the pulmonary pathophysiology of PE is important in risk-stratifying patients to determine treatment with anticoagulation alone or consideration for catheter-directed therapies (thrombolytics or mechanical thrombectomy), systemic thrombolytics, or surgical intervention.

Does CPD cause pulmonary artery pressure to increase?

Patients with preexisting CPD have diminished pulmonary vascular reserve and a smaller degree of obstruction can lead to disproportionate increase in pulmonary artery pressure and hemodynamic instability. 76

What is pulmonary embolism?

Pulmonary embolism (PE) occurs when there is an acute obstruction of the pulmonary artery or one of its branches. It is commonly caused by a venous thrombus that has dislodged from its site of formation and embolized to the arterial blood supply of one of the lungs. The process of clot formation and embolization is termed thromboembolism. PE results in the elevation of the pulmonary vessel resistance as a consequence of not only mechanical obstruction of the capillary by the embolism, but also due to pulmonary vasoconstriction. When pulmonary vascular resistance occurs following an acute PE, the rapid increase in the right ventricular afterload might lead to the dilatation of the right ventricular wall and subsequent right heart failure.

What is PE in pulmonary?

PE results in the elevation of the pulmonary vessel resistance as a consequence of not only mechanical obstruction of the capillary by the embolism, but also due to pulmonary vasoconstriction. Pulmonary vasoconstriction can be either biochemically mediated, hypoxia induced, or reflex-induced. Several mediators are involved ...

What happens to the heart after PE?

When pulmonary vascular resistance occurs following an acute PE, the rapid increase in the right ventricular afterload might lead to the dilatation of the right ventricular wall and subsequent right heart failure. In addition, the elevated pulmonary vascular resistance causes a decrease in the left ventricular preload and consequently leads to systemic hypotension. In patients with underlying cardiopulmonary disease, the cardiac output suffers substantial deterioration in overall output as compared to otherwise healthy individuals.

Why does hypoxemia occur in acute PE?

In PE, hypoxemia occurs mainly due to the ventilation perfusion mismatch. In fact, in the setting of an acute PE, the ventilation to perfusion ratio (V/Q) increases and the dead space enlarges. In addition, the occurrence of right to left shunt also contributes to the hypoxemia among patients with PE.

Where does a thrombus circulate?

After its formation, a thrombus might dislodge from the site of origin and circulate through the inferior vena cava, into the right ventricle, and into the pulmonary vasculature.

What is the triad of thrombosis?

The development of thrombosis is classically due to a group of conditions referred to as Virchow's triad. Virchow's triad includes alterations in blood flow, factors in the vessel wall, and factors affecting the properties of the blood. It is common for more than one risk factor to be present.

Where does PE come from?

Clot Formation. Most PE commonly originate from a thrombus that has formed in the iliofemoral vein, deep within the vasculature of the lower extremity. Less commonly, a PE may also arise from a thrombus in the upper extremity veins, renal veins, or pelvic veins.

Where does pulmonary embolism occur?

Pulmonary embolism occurs when a clump of material, most often a blood clot, gets wedged into an artery in your lungs. These blood clots most commonly come from the deep veins of your legs, a condition known as deep vein thrombosis (DVT).

What are the symptoms of pulmonary embolism?

Other signs and symptoms that can occur with pulmonary embolism include: Rapid or irregular heartbeat. Lightheadedness or dizziness. Excessive sweating. Fever. Leg pain or swelling, or both, usually in the calf caused by a deep vein thrombosis.

What are the risks of having a blood clot?

You're at higher risk if you or any of your family members have had venous blood clots or pulmonary embolism in the past. In addition, some medical conditions and treatments put you at risk, such as: Heart disease. Cardiovascular disease, specifically heart failure, makes clot formation more likely. Cancer.

What is PE in a lung?

Pulmonary embolism (PE) occurs when a blood clot gets lodged in an artery in the lung, blocking blood flow to part of the lung. Blood clots most often start in the legs and travel up through the right side of the heart and into the lungs. This is called DVT. However, PE sometimes can occur without any evidence of DVT.

What is it called when you have multiple clots in your lungs?

The portions of lung served by each blocked artery are robbed of blood and may die. This is known as pulmonary infarction. This makes it more difficult for your lungs to provide oxygen to the rest of your body.

What is the best treatment for pulmonary embolism?

For this reason, most hospitals are aggressive about taking measures to prevent blood clots, including: Blood thinners (anticoagulants).

How to get rid of pulmonary embolism?

Elevating your legs when possible and during the night also can be very effective. Raise the bottom of your bed 4 to 6 inches (10 to 15 cm) with blocks or books. Physical activity. Moving as soon as possible after surgery can help prevent pulmonary embolism and hasten recovery overall.

What are the symptoms of a pulmonary embolism?

Symptoms of a pulmonary embolism include sudden shortness of breath, pain in and around the chest and coughing. Caused by a blood clot, a pulmonary embolism is a serious but very treatable condition if done immediately. Appointments & Access. Contact Us.

How to reduce the risk of pulmonary embolism?

Be sure you discuss and understand your follow- up care with your doctor. Follow your doctor’s recommendations to reduce the risk of another pulmonary embolism. Keep all appointments with your doctor and the laboratory so your response to prescribed treatments can be monitored.

What is the term for a blood clot in the lung?

A pulmonary embolism is a blood clot in the lung that occurs when a clot in another part of the body (often the leg or arm) moves through the bloodstream and becomes lodged in the blood vessels of the lung. This restricts blood flow to the lungs, lowers oxygen levels in the lungs and increases blood pressure in the pulmonary arteries.

What is it called when a clot develops in a vein?

If a clot develops in a vein and it stays there, it’s called a thrombus. If the clot detaches from the wall of the vein and travels to another part of your body, it’s called an embolus. If PEs are not treated quickly, they can cause heart or lung damage and even death. Cleveland Clinic is a non-profit academic medical center.

What tests are done to identify blood clots?

Blood tests (including the D-dimer test). Pulmonary angiogram. Ultrasound of the leg -- helps to identify blood clots in patients who cannot have an X-ray due to dye allergies or who are too sick to leave their hospital room. Magnetic resonance imaging (MRI) of the legs or lungs.

Can pulmonary embolism cause shortness of breath?

Although most people with a pulmonary embolism experience symptoms, some will not. The first signs are usually shortness of breath and chest pains that get worse if you exert yourself. You may cough up bloody sputum. If you have these symptoms get medical attention right away.

Can a pulmonary embolism dissolve on its own?

A pulmonary embolism may dissolve on its own; it is seldom fatal when diagnosed and treated properly. However, if left untreated, it can be serious, leading to other medical complications, including death. A pulmonary embolism can: Cause heart damage. Be life-threatening, depending on the size of the clot.

What is a pulmonary embolism?

A pulmonary embolism (PE) is a blood clot that develops in a blood vessel in the body (often in the leg). It then travels to a lung artery where it suddenly blocks blood flow.

How is pulmonary embolism diagnosed?

Pulmonary embolism (PE) is often difficult to diagnose because the symptoms of PE are a lot like those of many other conditions and diseases.

What is it called when a blood clot forms in a blood vessel?

A blood clot that forms in a blood vessel in one area of the body, breaks off, and travels to another area of the body in the blood is called an embolus. An embolus can lodge itself in a blood vessel. This can block the blood supply to a particular organ. This blockage of a blood vessel by an embolus is called an embolism.

Where do clots occur in the body?

Venous clots most often happen in the deep veins of the legs. This is called deep vein thrombosis (DVT). Once a clot has formed in the deep veins of the leg, there is a potential for part of the clot to break off and travel through the blood to another area of the body, often the lung. DVT is the most common cause of a pulmonary embolism.

What is the circulatory system?

The heart, arteries, capillaries, and veins make up the body's circulatory system. Blood is pumped with great force from the heart into the arteries. From there blood flows into the capillaries (tiny blood vessels in the tissues). Blood returns to the heart through the veins. As it moves through the veins back to the heart, blood flow slows. Sometimes this slower blood flow may lead to clot formation.

Where do blood clots form?

Blood clots can form in arteries and veins. Clots formed in veins are called venous clots. Veins of the legs can be superficial veins (close to the surface of the skin) or deep veins (located near the bone and surrounded by muscle). Venous clots most often happen in the deep veins of the legs.

Why is PE so difficult to diagnose?

PE is often difficult to diagnose because the signs and symptoms of PE are a lot like those of many other conditions and diseases. Imaging tests and blood tests are used to look for a PE.

How many deaths are caused by pulmonary embolism?

Pulmonary embolism (PE) is responsible for approximately 100,000 to 200,000 deaths in the United States each year. With a diverse range of clinical presentations from asymptomatic to death, diagnosing PE can be challenging. Various resources are available, such as clinical scoring systems, laboratory data, and imaging studies which help guide clinicians in their work-up of PE. Prompt recognition and treatment are essential for minimizing the mortality and morbidity associated with PE. Advances in recognition and treatment have also enabled treatment of some patients in the home setting and limited the amount of time spent in the hospital. This article will review the risk factors, pathophysiology, clinical presentation, evaluation, and treatment of PE.

What is PE in pulmonary artery?

PE occurs when deep venous thrombi detach and embolize to the pulmonary circulation. Pulmonary vascular occlusion occurs and impairs gas exchange and circulation. In the lungs, the lower lobes are more frequently affected than the upper, with bilateral lung involvement being common.

What is the third most common cause of cardiovascular death after myocardial infarction?

Venous thromboembolism (VTE) and PE is the third most common cause of cardiovascular death after myocardial infarction (MI) and cerebrovascular accidents (CVA).[1] Many PEs are likely undiagnosed and calculating the true incidence remains challenging. However, PE remains a significant cause of preventable in-hospital mortality.

Why is it important to recognize a PE?

Prompt recognition of a PE is crucial because of the high associated mortality and morbidity, which may be prevented with early treatment. Failure to diagnose PE is a serious management error since 30% of untreated patients die, while only 8% succumb with effective therapy.[5] Unfortunately, PE may be asymptomatic or present with sudden death. Characteristic signs and symptoms such as tachycardia, dyspnea, chest pain, hypoxemia, and shock are non-specific and are present in many other conditions, such as acute MI, congestive heart failure, or pneumonia. In the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) trial, patients with PE had a range of signs and symptoms. Common signs were tachypnea (54%) and tachycardia (24%). The most common symptoms were dyspnea, usually of onset within seconds, at rest or with exertion (73%), pleuritic pain (44%), calf or thigh pain (44%), calf or thigh swelling (41%), and cough (34%).[6] With only 24% of patients presenting with tachycardia, the majority of patients lacked one of the most common findings. Additionally, PIOPED II excluded many types of patients, such as those with chronic elevated creatinine levels or receiving dialysis, critically ill patients, or people with recent MI. Applicability is therefore limited. Therefore, a high index of suspicion and assessment of risk factors are critical for the recognition of pulmonary embolic events.

What is PERC in thrombosis?

Beyond the Wells and Geneva systems, which clinicians use to help rule in thrombosis, the PE Rule-Out Criteria (PERC) can help rule-out PE in low-risk emergency department patients. PERC criteria are listed in Table 5.

Is PE asymptomatic or asymptomatic?

Unfortunately, PE may be asymptomatic or present with sudden death. Characteristic signs and symptoms such as tachycardia, dyspnea, chest pain, hypoxemia, and shock are non-specific and are present in many other conditions, such as acute MI, congestive heart failure, or pneumonia.

Can PE cause pulmonary infarction?

Peripheral PE can lead to pulmonary infarction, manifested by intra-alveolar hemorrhage. Pulmonary infarction occurs in about 10% of patients without underlying cardiopulmonary disease. Obstruction of the pulmonary arteries creates dead space ventilation as alveolar ventilation exceeds pulmonary capillary blood flow.

7 Pulmonary Embolism

Describe the factors contributing to the occurrence of pulmonary embolism.

Pathology of Pulmonary Embolism (PE)

About 90 percent of PEs are caused by deep vein thrombi, but at least one of three main predisposing factors ( Virchow’s triad ) are present in a case of PE:

Clinical Signs of PE

The clinical manifestations of PE vary widely, from asymptomatic when emboli are small or few, to sudden death when they are large or numerous.

What are the clinical features of pulmonary embolism?

Nearly all patients with pulmonary embolism will have one or more of the following clinical features—dyspnoea of sudden onset, tachypnoea (> 20 breaths/minute), or chest pain (pleuritic or substernal) 2; if the clinician remembers these three features, the possibility of pulmonary embolism will rarely be overlooked. When these clinical features are associated with ECG signs of right ventricular strain and/or radiologic signs of plump hilum, pulmonary infarction or oligaemia, the likelihood of pulmonary embolism is high, and it is further strengthened in the presence of risk factors for venous thromboembolism and arterial hypoxaemia with hypocapnia. 4 On the contrary, the absence of all these three clinical features virtually excludes the diagnosis of pulmonary embolism.

How to diagnose pulmonary embolism?

1 2 Very rarely, pulmonary embolism presents in such a dramatic fashion that the diagnosis is intuitively obvious and treatment will be started, but the usual presentation is frequently vague and variable in severity, so that further testing is necessary to establish or exclude the diagnosis. 2 Diagnostic evaluation is best carried out by first attempt ing to identify a provable alternative diagnosis that can explain the patient's symptoms.

What are the findings of a chest radiograph?

Chest radiograph findings are also non-specific but may be helpful. A normal film is compatible with all types of acute pulmonary embolism; in fact, a normal film in a patient with severe acute dyspnoea without wheezing is very suspicious of pulmonary embolism. The lung fields may show evidence of pulmonary infarction: peripheral opacities, sometimes wedge shaped or semicircular, arranged along the pleural surface (so called Hampton's hump). Atelectasis, small pleural effusions, and raised diaphragm have low specificity for pulmonary embolism. In massive pulmonary embolism a plump pulmonary artery shadow may be seen when the pulmonary artery pressure is elevated. It may be possible to detect areas of oligaemia in the parts of the lung affected by emboli (Westermark sign), but this is difficult on the type of film usually available in the acute situation. The radiograph is especially valuable in excluding other conditions mimicking pulmonary embolism (pneumothorax, pneumonia, left heart failure, tumour, rib fracture, massive pleural effusion, lobar collapse), but pulmonary embolism may coexist with other cardiopulmonary processes. The radiograph is also necessary for the proper interpretation of the lung scan.

How to determine clinical likelihood of pulmonary embolism?

Clinical likelihood of pulmonary embolism is determined after consideration of risk factors (the most common being immobilisation, a history of previous venous thromboembolism, lower limb fractures, and recent surgery), presentation, and basic investigations (ECG and plain chest radiograph). Although the characteristics of these clinical estimates have not been extensively validated, those generally accepted are given in table 4.

What is the most common presentation of pulmonary embolism?

The first and most common presentation is dyspnoea with or without pleuritic pain and haemoptysis (acute minor pulmonary embolism). The second presentation is haemodynamic instability, which is associated with acute massive pulmonary embolism.

Why is the right ventricular systolic pressure higher than in acute pulmonary embolism?

This is caused by multiple small or moderately sized emboli that accumulate over several weeks. Because the obstruction occurs slowly, there is time for the right ventricle to adapt and for some hypertrophy to develop ; consequently, the right ventricular systolic pressure is higher than in acute pulmonary embolism.

When to use pulmonary angiography?

Occasionally, pulmonary angiography is used when the clinical likelihood is low despite the fact that other tests indicate pulmonary embolism. Angiography is also indicated if there are special reasons why the diagnosis must be confirmed beyond doubt (for example, when the risk from anticoagulation is higher than normal or when suspected recurrent emboli have led to frequent admissions to hospital, often in the absence of any firm evidence of venous thromboembolism).

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