ower extremity venous thromboembolism (VTE), including deep vein thrombosis (DVT) of the leg, is common. 1 The incidence rate for DVT ranges from 88 to 112 per 100 000 person-years. 2 Rates of recurrent VTE range from 20% to 36% during the 10 years after an initial event. 3,4 Isolated distal DVT, defined as thrombosis involving 1 or more of the deep calf veins without reaching the popliteal vein, is associated with a 1-year all-cause mortality rate of 4.6 per 100 person-years (95% CI, 3.8-5.7). 5 This review provides an evidence-based update of the diagnosis and therapy of lower extremity DVT.
MethodsWe searched PubMed and the Cochrane databases for Englishlanguage studies published from January 2015 through June 2020 for randomized clinical trials, meta-analyses, systematic reviews, and observational studies, resulting in 2125 retrieved articles (see eAppendix in the Supplement for search terms). We manually searched references of selected articles, reviews, meta-analyses, and practice guidelines. Selected articles were mutually agreed on by the authors. A total of 86 articles (20 randomized clinical trials, 20 systematic reviews and meta-analyses, 33 observational cohort studies, 7 reviews, and 6 guideline documents) were included in the final review. Randomized clinical trials and meta-analyses and information of interest to a general medical readership were prioritized.
Risk Factors for VTEMost patients with VTE have multiple risk factors for VTE (Table 1). Risk factors include demographic factors (eg, older age, IMPORTANCE Incidence rates for lower extremity deep vein thrombosis (DVT) range from 88 to 112 per 100 000 person-years and increase with age. Rates of recurrent VTE range from 20% to 36% during the 10 years after an initial event.OBSERVATIONS PubMed and Cochrane databases were searched for English-language studies published from January 2015 through June 2020 for randomized clinical trials, meta-analyses, systematic reviews, and observational studies. Risk factors for venous thromboembolism (VTE), such as older age, malignancy (cumulative incidence of 7.4% after a median of 19 months), inflammatory disorders (VTE risk is 4.7% in patients with rheumatoid arthritis and 2.5% in those without), and inherited thrombophilia (factor V Leiden carriers with a 10-year cumulative incidence of 10.9%), are associated with higher risk of VTE. Patients with signs or symptoms of lower extremity DVT, such as swelling (71%) or a cramping or pulling discomfort in the thigh or calf (53%), should undergo assessment of pretest probability followed by D-dimer testing and imaging with venous ultrasonography. A normal D-dimer level (ie, D-dimer <500 ng/mL) excludes acute VTE when combined with a low pretest probability (ie, Wells DVT score Յ1). In patients with a high pretest probability, the negative predictive value of a D-dimer less than 500 ng/mL is 92%. Consequently, D-dimer cannot be used to exclude DVT without an assessment of pretest probability. Postthrombotic syndrome, defined as persistent symptoms, signs of ch...