Whether and How to Prescribe Anticoagulants to Patients With Isolated Distal DVT Summary of the Evidence AT9 discouraged routine whole-leg US examinations (ie, including the distal veins) in patients with suspected DVT, thereby reducing how often isolated distal DVT is The rationale for not routinely examining the distal veins in patients who have had proximal DVT excluded is that: (1) other assessment may already indicate that isolated distal DVT is either unlikely to be present or unlikely to cause complications if it is present (eg, low clinical probability of DVT, D-dimer is negative); (2) if these conditions are not met, a repeat US examination of the proximal veins can be done after a week to detect possible DVT extension and the need for treatment; and (3) false-positive ndings for DVT occur more often with US examinations of the distal compared with the proximal veins.1,73,74 If the calf veins are imaged (usually with US) and isolated distal DVT is diagnosed, there are two management options: (1) treat patients with anticoagulant therapy or (2) do not treat patients with anticoagulant therapy unless extension of their DVT is detected on a follow-up US examination (eg, after 1 and TABLE 13 ] Summary of Findings: Aspirin vs Placebo for Extended Treatment of VTE Outcomes No. of Participants (Studies) Follow-up Quality of the Evidence (GRADE) Relative Effect Anticipated Absolute Effects Risk with Control Risk Difference with Aspirin (95% CI) All-cause mortality Up to 4 y Lowa,b because of imprecision Moderate-Risk Populationd (from 3 fewer to 3 more) Recurrent VTE 1,224 Up to 4 y Moderatea because of imprecision (from 24 fewer to 89 fewer) Major bleeding 1,224 Up to 4 y Moderatea,b because of imprecision (from 6 fewer to 29 more) The basis for the assumed risk (eg, the median control group risk across studies) is provided in the footnotes. 