Deep vein thrombosis (DVT) is one condition within the broader category of venous thromboembolism (VTE). Under normal circumstances, blood flows rapidly through the veins and clot formation is uncommon. In the legs, this flow is aided by muscle contractions, which compress the veins during movement. Occasionally, DVT can develop without an identifiable cause. Prolonged immobility slows venous circulation, and reduced flow increases the likelihood of clot formation. Many healthcare professionals mistakenly believe that this potentially fatal condition is rare in their facility or patient population. Although an individual clinician may encounter only a limited number of cases, DVT remains a significant public health concern. This study examined whether a structured teaching program could help patients manage complications following orthopedic lower limb injuries, as well as facilitate the exchange of important DVT-related information between patients and healthcare providers, with opportunities for timely feedback.
Epidemiology
Anatomy
Pathophysiology
The development of DVT is classically explained by Virchow’s triad, which includes venous stasis, endothelial injury, and hypercoagulability. Venous stasis can occur due to immobility, prolonged bed rest, or paralysis. Endothelial injury may result from surgery, trauma, or the presence of a central venous catheter. Hypercoagulability may be inherited, as in cases of factor V Leiden mutation, or acquired, such as in malignancy, pregnancy, or the use of hormonal therapy. Additional common risk factors include major orthopedic surgery, active cancer, prolonged immobilization, previous VTE, obesity, congestive heart failure, and chronic inflammatory disorders. These factors may act synergistically to increase the risk of thrombus formation.
Principles of Risk Stratification
Risk stratification aims to estimate the pretest probability of DVT to direct appropriate diagnostic and therapeutic steps. The process balances sensitivity and specificity to avoid missing a diagnosis in high-risk patients while preventing unnecessary imaging in low-risk individuals. It relies on validated clinical prediction rules, such as the Wells or Revised Geneva scores, combined with selective use of D-dimer testing and imaging. Low-risk patients with a negative D-dimer can often have DVT safely excluded without further imaging, while high-risk patients require immediate imaging and possible treatment.
Etiology
Genetics
Prognostic Factors
Clinical History
Clinical Prediction Models
Wells Score for DVT
The Wells score assigns points based on clinical features such as active cancer, paralysis or recent immobilization, recent surgery or prolonged bed rest, localized tenderness, swelling of the entire leg, calf swelling greater than 3 cm compared with the asymptomatic leg, pitting edema, collateral superficial veins, and a history of previous DVT. Two points are subtracted if an alternative diagnosis is as likely as DVT. In the three-tier model, a score of three or more indicates high risk, one to two points suggests moderate risk, and zero or fewer points indicates low risk. In the simplified two-tier model, scores of two or more are considered “likely,” and scores below two are “unlikely” for DVT.
Revised Geneva Score
The Revised Geneva score uses fewer variables and assigns one point each for active cancer, unilateral lower limb pain, recent bed rest of three or more days, a history of VTE, and pain on deep vein palpation with unilateral edema. Scores of zero to one indicate low risk, two to three suggest moderate risk, and four or more indicate high risk. Although simpler than the Wells score, it is less widely used for DVT than for pulmonary embolism assessment.
Physical Examination
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
The diagnostic approach begins with estimating pretest probability using the Wells or Revised Geneva score. In patients with low probability, a D-dimer assay is performed. A negative result in this group effectively rules out DVT, while a positive result prompts compression ultrasonography. In patients with high pretest probability, imaging is performed directly without D-dimer testing, as the risk of missing a diagnosis is unacceptable. If the initial ultrasound is negative but clinical suspicion remains high, repeat imaging after several days may be warranted. This structured approach improves diagnostic efficiency while minimizing unnecessary tests.
Laboratory Studies
D-dimer is a fibrin degradation product and serves as a sensitive but non-specific marker for thrombosis. ELISA-based assays have sensitivities exceeding 95%, making them highly effective in ruling out DVT in low-risk patients. However, the specificity is low, as elevated levels can occur in infection, inflammation, trauma, pregnancy, and malignancy. Quantitative latex agglutination and immunoturbidimetric assays are alternative methods. The main role of D-dimer testing is in excluding DVT in low or intermediate pretest probability patients, thereby avoiding unnecessary imaging.
Risk Stratification
The Wells clinical prediction rule is a validated tool used to estimate the likelihood of deep venous thrombosis (DVT) before diagnostic testing. It allows clinicians to categorize patients into low-, moderate-, or high-risk groups based on their pretest probability. When combined with objective diagnostic tests, this approach streamlines the evaluation process for individuals with suspected DVT. The scoring system considers known risk factors, relevant clinical findings, and whether an alternative diagnosis is more likely than DVT.
Clinical Feature
Score
Previous history of confirmed DVT
+1
Active malignancy (receiving treatment, treated within past 6 months, or palliative care)
+1
Bed rest for ≥3 days or major surgery within the past 4 weeks
+1
Paralysis, paresis, or recent casting of a lower limb
+1
Entire leg swelling
+1
Calf circumference > 3 cm larger than the opposite leg
+1
Localized tenderness along the deep vein pathway
+1
Pitting edema confined to the affected limb
+1
Presence of superficial collateral veins (non-varicose)
+1
Alternative diagnosis at least as likely as DVT
−2
The Wells DVT score can be used to classify patients into either two or three risk categories.
Three-tier model: A total score of ≤0 indicates low risk, a score of 1–2 indicates moderate risk, and a score of ≥3 indicates high risk.
Two-tier model: Patients are grouped as DVT unlikely if the score is less than 2, and DVT likely if the score is 2 or higher.
Three-Category Model
Wells Score
Estimated Probability of DVT
High risk
>2
53%
Moderate risk
1-2
17%
Low risk
0
5%
Two-Category Model
Wells Score
Estimated Probability of DVT
High risk (DVT likely)
2 or more
28%
Low risk (DVT unlikely)
Less than 2
6%
This risk group classification is used alongside the results of a highly sensitive D-dimer test, such as an enzyme-linked immunosorbent assay (ELISA) or quantitative latex/immunoturbidimetric method.
In the two-category model:
DVT unlikely: If the pretest score suggests a low probability and the D-dimer is negative, DVT can be excluded. If the D-dimer is positive, further imaging such as duplex ultrasonography is indicated. A negative imaging result rules out DVT, while a positive result confirms the diagnosis and warrants treatment.
DVT likely: Both D-dimer testing and diagnostic imaging should be performed. A positive imaging result confirms DVT and requires treatment. If both the imaging and D-dimer are negative, DVT is excluded. When imaging is negative but the D-dimer is positive, most experts recommend repeating the imaging study after one week. A positive follow-up scan confirms DVT and necessitates treatment; a negative result rules it out.
Deep vein thrombosis (DVT) is one condition within the broader category of venous thromboembolism (VTE). Under normal circumstances, blood flows rapidly through the veins and clot formation is uncommon. In the legs, this flow is aided by muscle contractions, which compress the veins during movement. Occasionally, DVT can develop without an identifiable cause. Prolonged immobility slows venous circulation, and reduced flow increases the likelihood of clot formation. Many healthcare professionals mistakenly believe that this potentially fatal condition is rare in their facility or patient population. Although an individual clinician may encounter only a limited number of cases, DVT remains a significant public health concern. This study examined whether a structured teaching program could help patients manage complications following orthopedic lower limb injuries, as well as facilitate the exchange of important DVT-related information between patients and healthcare providers, with opportunities for timely feedback.
The development of DVT is classically explained by Virchow’s triad, which includes venous stasis, endothelial injury, and hypercoagulability. Venous stasis can occur due to immobility, prolonged bed rest, or paralysis. Endothelial injury may result from surgery, trauma, or the presence of a central venous catheter. Hypercoagulability may be inherited, as in cases of factor V Leiden mutation, or acquired, such as in malignancy, pregnancy, or the use of hormonal therapy. Additional common risk factors include major orthopedic surgery, active cancer, prolonged immobilization, previous VTE, obesity, congestive heart failure, and chronic inflammatory disorders. These factors may act synergistically to increase the risk of thrombus formation.
Principles of Risk Stratification
Risk stratification aims to estimate the pretest probability of DVT to direct appropriate diagnostic and therapeutic steps. The process balances sensitivity and specificity to avoid missing a diagnosis in high-risk patients while preventing unnecessary imaging in low-risk individuals. It relies on validated clinical prediction rules, such as the Wells or Revised Geneva scores, combined with selective use of D-dimer testing and imaging. Low-risk patients with a negative D-dimer can often have DVT safely excluded without further imaging, while high-risk patients require immediate imaging and possible treatment.
Clinical Prediction Models
Wells Score for DVT
The Wells score assigns points based on clinical features such as active cancer, paralysis or recent immobilization, recent surgery or prolonged bed rest, localized tenderness, swelling of the entire leg, calf swelling greater than 3 cm compared with the asymptomatic leg, pitting edema, collateral superficial veins, and a history of previous DVT. Two points are subtracted if an alternative diagnosis is as likely as DVT. In the three-tier model, a score of three or more indicates high risk, one to two points suggests moderate risk, and zero or fewer points indicates low risk. In the simplified two-tier model, scores of two or more are considered “likely,” and scores below two are “unlikely” for DVT.
Revised Geneva Score
The Revised Geneva score uses fewer variables and assigns one point each for active cancer, unilateral lower limb pain, recent bed rest of three or more days, a history of VTE, and pain on deep vein palpation with unilateral edema. Scores of zero to one indicate low risk, two to three suggest moderate risk, and four or more indicate high risk. Although simpler than the Wells score, it is less widely used for DVT than for pulmonary embolism assessment.
The diagnostic approach begins with estimating pretest probability using the Wells or Revised Geneva score. In patients with low probability, a D-dimer assay is performed. A negative result in this group effectively rules out DVT, while a positive result prompts compression ultrasonography. In patients with high pretest probability, imaging is performed directly without D-dimer testing, as the risk of missing a diagnosis is unacceptable. If the initial ultrasound is negative but clinical suspicion remains high, repeat imaging after several days may be warranted. This structured approach improves diagnostic efficiency while minimizing unnecessary tests.
D-dimer is a fibrin degradation product and serves as a sensitive but non-specific marker for thrombosis. ELISA-based assays have sensitivities exceeding 95%, making them highly effective in ruling out DVT in low-risk patients. However, the specificity is low, as elevated levels can occur in infection, inflammation, trauma, pregnancy, and malignancy. Quantitative latex agglutination and immunoturbidimetric assays are alternative methods. The main role of D-dimer testing is in excluding DVT in low or intermediate pretest probability patients, thereby avoiding unnecessary imaging.
Risk Stratification
The Wells clinical prediction rule is a validated tool used to estimate the likelihood of deep venous thrombosis (DVT) before diagnostic testing. It allows clinicians to categorize patients into low-, moderate-, or high-risk groups based on their pretest probability. When combined with objective diagnostic tests, this approach streamlines the evaluation process for individuals with suspected DVT. The scoring system considers known risk factors, relevant clinical findings, and whether an alternative diagnosis is more likely than DVT.
Clinical Feature
Score
Previous history of confirmed DVT
+1
Active malignancy (receiving treatment, treated within past 6 months, or palliative care)
+1
Bed rest for ≥3 days or major surgery within the past 4 weeks
+1
Paralysis, paresis, or recent casting of a lower limb
+1
Entire leg swelling
+1
Calf circumference > 3 cm larger than the opposite leg
+1
Localized tenderness along the deep vein pathway
+1
Pitting edema confined to the affected limb
+1
Presence of superficial collateral veins (non-varicose)
+1
Alternative diagnosis at least as likely as DVT
−2
The Wells DVT score can be used to classify patients into either two or three risk categories.
Three-tier model: A total score of ≤0 indicates low risk, a score of 1–2 indicates moderate risk, and a score of ≥3 indicates high risk.
Two-tier model: Patients are grouped as DVT unlikely if the score is less than 2, and DVT likely if the score is 2 or higher.
Three-Category Model
Wells Score
Estimated Probability of DVT
High risk
>2
53%
Moderate risk
1-2
17%
Low risk
0
5%
Two-Category Model
Wells Score
Estimated Probability of DVT
High risk (DVT likely)
2 or more
28%
Low risk (DVT unlikely)
Less than 2
6%
This risk group classification is used alongside the results of a highly sensitive D-dimer test, such as an enzyme-linked immunosorbent assay (ELISA) or quantitative latex/immunoturbidimetric method.
In the two-category model:
DVT unlikely: If the pretest score suggests a low probability and the D-dimer is negative, DVT can be excluded. If the D-dimer is positive, further imaging such as duplex ultrasonography is indicated. A negative imaging result rules out DVT, while a positive result confirms the diagnosis and warrants treatment.
DVT likely: Both D-dimer testing and diagnostic imaging should be performed. A positive imaging result confirms DVT and requires treatment. If both the imaging and D-dimer are negative, DVT is excluded. When imaging is negative but the D-dimer is positive, most experts recommend repeating the imaging study after one week. A positive follow-up scan confirms DVT and necessitates treatment; a negative result rules it out.
Deep vein thrombosis (DVT) is one condition within the broader category of venous thromboembolism (VTE). Under normal circumstances, blood flows rapidly through the veins and clot formation is uncommon. In the legs, this flow is aided by muscle contractions, which compress the veins during movement. Occasionally, DVT can develop without an identifiable cause. Prolonged immobility slows venous circulation, and reduced flow increases the likelihood of clot formation. Many healthcare professionals mistakenly believe that this potentially fatal condition is rare in their facility or patient population. Although an individual clinician may encounter only a limited number of cases, DVT remains a significant public health concern. This study examined whether a structured teaching program could help patients manage complications following orthopedic lower limb injuries, as well as facilitate the exchange of important DVT-related information between patients and healthcare providers, with opportunities for timely feedback.
The development of DVT is classically explained by Virchow’s triad, which includes venous stasis, endothelial injury, and hypercoagulability. Venous stasis can occur due to immobility, prolonged bed rest, or paralysis. Endothelial injury may result from surgery, trauma, or the presence of a central venous catheter. Hypercoagulability may be inherited, as in cases of factor V Leiden mutation, or acquired, such as in malignancy, pregnancy, or the use of hormonal therapy. Additional common risk factors include major orthopedic surgery, active cancer, prolonged immobilization, previous VTE, obesity, congestive heart failure, and chronic inflammatory disorders. These factors may act synergistically to increase the risk of thrombus formation.
Principles of Risk Stratification
Risk stratification aims to estimate the pretest probability of DVT to direct appropriate diagnostic and therapeutic steps. The process balances sensitivity and specificity to avoid missing a diagnosis in high-risk patients while preventing unnecessary imaging in low-risk individuals. It relies on validated clinical prediction rules, such as the Wells or Revised Geneva scores, combined with selective use of D-dimer testing and imaging. Low-risk patients with a negative D-dimer can often have DVT safely excluded without further imaging, while high-risk patients require immediate imaging and possible treatment.
Clinical Prediction Models
Wells Score for DVT
The Wells score assigns points based on clinical features such as active cancer, paralysis or recent immobilization, recent surgery or prolonged bed rest, localized tenderness, swelling of the entire leg, calf swelling greater than 3 cm compared with the asymptomatic leg, pitting edema, collateral superficial veins, and a history of previous DVT. Two points are subtracted if an alternative diagnosis is as likely as DVT. In the three-tier model, a score of three or more indicates high risk, one to two points suggests moderate risk, and zero or fewer points indicates low risk. In the simplified two-tier model, scores of two or more are considered “likely,” and scores below two are “unlikely” for DVT.
Revised Geneva Score
The Revised Geneva score uses fewer variables and assigns one point each for active cancer, unilateral lower limb pain, recent bed rest of three or more days, a history of VTE, and pain on deep vein palpation with unilateral edema. Scores of zero to one indicate low risk, two to three suggest moderate risk, and four or more indicate high risk. Although simpler than the Wells score, it is less widely used for DVT than for pulmonary embolism assessment.
The diagnostic approach begins with estimating pretest probability using the Wells or Revised Geneva score. In patients with low probability, a D-dimer assay is performed. A negative result in this group effectively rules out DVT, while a positive result prompts compression ultrasonography. In patients with high pretest probability, imaging is performed directly without D-dimer testing, as the risk of missing a diagnosis is unacceptable. If the initial ultrasound is negative but clinical suspicion remains high, repeat imaging after several days may be warranted. This structured approach improves diagnostic efficiency while minimizing unnecessary tests.
D-dimer is a fibrin degradation product and serves as a sensitive but non-specific marker for thrombosis. ELISA-based assays have sensitivities exceeding 95%, making them highly effective in ruling out DVT in low-risk patients. However, the specificity is low, as elevated levels can occur in infection, inflammation, trauma, pregnancy, and malignancy. Quantitative latex agglutination and immunoturbidimetric assays are alternative methods. The main role of D-dimer testing is in excluding DVT in low or intermediate pretest probability patients, thereby avoiding unnecessary imaging.
Risk Stratification
The Wells clinical prediction rule is a validated tool used to estimate the likelihood of deep venous thrombosis (DVT) before diagnostic testing. It allows clinicians to categorize patients into low-, moderate-, or high-risk groups based on their pretest probability. When combined with objective diagnostic tests, this approach streamlines the evaluation process for individuals with suspected DVT. The scoring system considers known risk factors, relevant clinical findings, and whether an alternative diagnosis is more likely than DVT.
Clinical Feature
Score
Previous history of confirmed DVT
+1
Active malignancy (receiving treatment, treated within past 6 months, or palliative care)
+1
Bed rest for ≥3 days or major surgery within the past 4 weeks
+1
Paralysis, paresis, or recent casting of a lower limb
+1
Entire leg swelling
+1
Calf circumference > 3 cm larger than the opposite leg
+1
Localized tenderness along the deep vein pathway
+1
Pitting edema confined to the affected limb
+1
Presence of superficial collateral veins (non-varicose)
+1
Alternative diagnosis at least as likely as DVT
−2
The Wells DVT score can be used to classify patients into either two or three risk categories.
Three-tier model: A total score of ≤0 indicates low risk, a score of 1–2 indicates moderate risk, and a score of ≥3 indicates high risk.
Two-tier model: Patients are grouped as DVT unlikely if the score is less than 2, and DVT likely if the score is 2 or higher.
Three-Category Model
Wells Score
Estimated Probability of DVT
High risk
>2
53%
Moderate risk
1-2
17%
Low risk
0
5%
Two-Category Model
Wells Score
Estimated Probability of DVT
High risk (DVT likely)
2 or more
28%
Low risk (DVT unlikely)
Less than 2
6%
This risk group classification is used alongside the results of a highly sensitive D-dimer test, such as an enzyme-linked immunosorbent assay (ELISA) or quantitative latex/immunoturbidimetric method.
In the two-category model:
DVT unlikely: If the pretest score suggests a low probability and the D-dimer is negative, DVT can be excluded. If the D-dimer is positive, further imaging such as duplex ultrasonography is indicated. A negative imaging result rules out DVT, while a positive result confirms the diagnosis and warrants treatment.
DVT likely: Both D-dimer testing and diagnostic imaging should be performed. A positive imaging result confirms DVT and requires treatment. If both the imaging and D-dimer are negative, DVT is excluded. When imaging is negative but the D-dimer is positive, most experts recommend repeating the imaging study after one week. A positive follow-up scan confirms DVT and necessitates treatment; a negative result rules it out.
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