***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: International guidance has recently recommended serial proximal compression ultrasound ( CUS ) as first line imaging for suspected deep vein thrombosis ( DVT ) .  Single whole‐leg CUS is a routine alternative diagnostic strategy that can reduce repeated attendances and identify alternative pathology . We conducted a prospect i ve observational cohort study . Consecutive ambulatory , adult patients with suspected DVT and negative or inconclusive whole‐leg CUS had anticoagulation withheld  and were followed for 3 months . The primary outcome was a predefined clinical ly relevant adverse event rate . Secondary outcomes included technical failure , alternative diagnoses and all cause mortality . 212 patients agreed to participate and completed follow up . One patient was subsequently diagnosed with an isolated distal DVT . The adverse event rate was thus 1/212 , 0·47 % ( 95 % confidence interval [ CI ] 0·08–2·62 ) . Technical imaging failure occurred in 11·3 % of cases ( 95 % CI 7·7–16·3 ) . Several potential predictors of an inconclusive result were identified on multivariate analysis . 150 ( 70·8 % ) patients were provided with a documented alternative diagnosis . Patients who have anticoagulation withheld  following a negative or inconclusive whole‐leg CUS for suspected DVT have a low rate of adverse events . Technical failure remains an issue : several factors were significantly associated with inconclusive results and may warrant an alternative diagnostic approach BACKGROUND It remains unclear whether a single complete ultrasound examination , which detects calf vein thrombosis , is as safe as a baseline rapid ultrasound examination , repeated after 1 week when negative , which examines the veins in the groin and the knee . Therefore , we compared the safety and feasibility of two diagnostic ultrasound strategies , involving rapid and complete compression ultrasound ( CUS ) examination . METHODS Consecutive patients with suspected deep vein thrombosis ( DVT ) underwent clinical probability assessment . In patients with an unlikely clinical probability and a normal D-dimer finding , DVT was considered to be excluded . All others were r and omized to undergo a rapid or a single complete CUS examination . Patients in whom DVT was excluded were followed for 3 months to assess the incidence of venous thromboembolism ( VTE ) . RESULTS A total of 1002 patients were included . A clinical decision rule indicating DVT to be unlikely and a normal D-dimer finding occurred in 481 patients ( 48 % ) , with a VTE incidence of 0.4 % [ 95 % confidence interval ( CI ) 0.05 - 1.5 % ] during follow-up . DVT was confirmed in 59 of the 257 patients ( 23 % ) who underwent rapid CUS examination , and in 99 of the 264 patients ( 38 % ) who underwent complete CUS examination . VTE during follow-up occurred in four patients ( 2.0 % ; 95 % CI 0.6 - 5.1 % ) in the rapid CUS arm , and in two patients ( 1.2 % ; 95 % CI 0.2 - 4.3 % ) in the complete CUS arm . CONCLUSIONS A diagnostic strategy with a clinical decision rule , a D-dimer test and a CUS examination is safe and efficient . Both the rapid and the complete CUS test are comparable and efficient strategies , with differing advantages and disadvantages BACKGROUND Several diagnostic strategies using ultrasound imaging , measurement of D-dimer , and assessment of clinical probability of disease have proved safe in patients with suspected deep-vein thrombosis , but they have not been compared in r and omized trials . METHODS Out patients presenting with suspected lower-extremity deep-vein thrombosis were potentially eligible . Using a clinical model , physicians evaluated the patients and categorized them as likely or unlikely to have deep-vein thrombosis . The patients were then r and omly assigned to undergo ultrasound imaging alone ( control group ) or to undergo D-dimer testing ( D-dimer group ) followed by ultrasound imaging unless the D-dimer test was negative and the patient was considered clinical ly unlikely to have deep-vein thrombosis , in which case ultrasound imaging was not performed . RESULTS Five hundred thirty patients were r and omly assigned to the control group , and 566 to the D-dimer group . The overall prevalence of deep-vein thrombosis or pulmonary embolism was 15.7 percent . Among patients for whom deep-vein thrombosis had been ruled out by the initial diagnostic strategy , there were two confirmed venous thromboembolic events in the D-dimer group ( 0.4 percent ; 95 percent confidence interval , 0.05 to 1.5 percent ) and six events in the control group ( 1.4 percent ; 95 percent confidence interval , 0.5 to 2.9 percent ; P=0.16 ) during three months of follow-up . The use of D-dimer testing result ed in a significant reduction in the use of ultrasonography , from a mean of 1.34 tests per patient in the control group to 0.78 in the D-dimer group ( P=0.008 ) . Two hundred eighteen patients ( 39 percent ) in the D-dimer group did not require ultrasound imaging . CONCLUSIONS Deep-vein thrombosis can be ruled out in a patient who is judged clinical ly unlikely to have deep-vein thrombosis and who has a negative D-dimer test . Ultrasound testing can be safely omitted in such patients The purpose of this study was to determine the effect of anticoagulation on the incidence of thrombotic propagation and pulmonary embolism in patients with calf vein thrombosis after total hip or total knee arthroplasty . Patients undergoing arthroplasties had prospect i ve surveillance for postoperative deep vein thrombosis by both bilateral contrast venography and venous duplex scanning . Calf vein thrombosis was documented by venography in 42 patients ( 50 limbs ) , including 29 of 253 patients undergoing total hip arthroplasty ( 11.4 % ) and 13 of 99 patients undergoing total knee arthroplasty ( 13 % ) . Of patients on whom follow-up duplex scans were performed , heparin followed by warfarin anticoagulation was used in 11 ( 13 limbs ) and withheld in 21 ( 25 limbs ) . Propagation of thrombosis to the popliteal or superficial femoral vein or both was detected by serial duplex scanning in 3 of 13 treated limbs ( 23 % ) and 2 of 25 untreated limbs ( 8 % ) , ( p = 0.43 ) . All thrombus propagations were detected within 2 weeks of the operative procedure . There were no pulmonary emboli or deaths . Propagation of asymptomatic calf vein thrombosis after arthroplasty was not influenced by anticoagulation , suggesting that postoperative calf vein thrombosis need not be routinely treated . Serial venous duplex scanning is useful to identify the occasional patient in whom thrombotic propagation requiring anticoagulation develops OBJECTIVE This prospect i ve study determined the incidence of signs and symptoms of chronic venous disease and recurrent venous thrombotic events ( VTE ) in relation to the location and extent of the initial venous thrombus . METHODS A first episode of acute deep vein thrombosis ( DVT ) occurred in 120 lower extremities of 105 patients ( 59 men ; mean age , 54 years [ range , 23 - 82 years ] ) . Patients who presented with pain , swelling , or signs and symptoms of pulmonary embolism of < 10 days were included . The DVT was diagnosed with duplex ultrasound ( DUS ) imaging .  Patients were grouped by those having thrombosis in one venous segment ( group A ) or multiple levels ( group B ) . Patients were treated with heparin and warfarin . Patients with at least 1-year of follow-up with clinical and DUS were included . RESULTS No difference was found in the duration of signs and symptoms at presentation . The median follow-up was 3.4 years ( range , 1.2 - 7 years ) . More symptomatic limbs were seen in group B ( 71 of 79 ) compared with group A ( 21 of 41 ; P < .001 ) . Post-thrombotic syndrome ( PTS ) was more advanced in group B vs group A , including the prevalence of skin damage and ulceration ( 61 of 79 vs 26 of 41 , P < .001 ; 29 of 79 vs 6 of 41 , P = .019 , respectively ) . Limbs with calf DVT that had focal thrombosis were most often asymptomatic . Calf thrombosis in patients with proximal DVT produced the highest prevalence of PTS . Venous claudication was exclusively found in group B and was present only when iliac veins were involved . Recurrent thrombosis had a trend for a higher prevalence in group B ( 5 of 41 vs 16 of 79 , P = .39 ) . Reflux , obstruction , or a combination of the two were more common in group B ( 61 of 79 ) vs group A ( 15 of 41 ; P < .0001 ) . Limbs with both reflux and obstruction were more likely to develop skin damage ( group A , 5 of 6 vs 1 of 35 , P < .0001 ; group B , 24 of 29 vs 5 of 50 , P < .0001 ) . CONCLUSIONS Recurrent thrombosis and skin damage is more likely to develop in patients with multiple sites of thrombosis than in those with thrombosis in a single vein segment . Patients with reflux and obstruction presented more skin damage than those with reflux or obstruction alone . Involvement of the calf veins in the presence of proximal vein thrombosis increased the likelihood for PTS BACKGROUND Treatment of isolated calf muscle vein thrombosis ( ICMVT ) is controversial . There are no data from prospect i ve , controlled studies . Objective of this article was to compare the efficacy and safety of a short-term course of anticoagulation with compression therapy alone . METHODS We prospect ively r and omized patients with symptomatic , sonographically proven ICMVT in the soleal and /or gastrocnemial muscle veins in two treatment arms . The first received low-molecular-weight heparin for 10 days at therapeutic dosage ( nadroparin 180 anti-activated factor X units once daily ) and compression therapy for three months , and the second received compression therapy alone . Primary efficacy endpoint of the study was sonographically proven progression of ICMVT into the deep veins and clinical pulmonary embolism ( PE ) as confirmed by objective testing . Secondary efficacy and primary safety endpoints were major bleeding , death not due to PE , and complete sonographically proven recanalization of the muscle vein . We assessed transient and permanent risk factors for venous thromboembolism . RESULTS One-hundred seven patients were finally ruled eligible for evaluation : 89 % out patients , 11 % hospitalized patients . In the heparin group ( n=54 ) progression to deep vein thrombosis ( DVT ) occurred in two patients ( 3.7 % ) , in the group compression therapy alone ( n=53 ) progression to DVT occurred in two patients ( n.s . ) . No clinical PE and no death occurred . Thrombus recanalization after 3 months was not statistically significant different between the two study groups . No major bleeding occurred . CONCLUSION The data do not show superiority of a short-term regimen of low-molecular-weight heparin and compression therapy in comparison with compression therapy alone in patients with ICMVT in a rather low-risk population There is a lack of consensus on the value of detecting and treating symptomatic isolated distal deep-vein thrombosis ( DVT ) of the lower limbs . In our study , we compared the risk factors and outcomes in patients with isolated symptomatic distal DVT with those with proximal symptomatic DVT . We analysed the data of patients with objective ly confirmed symptomatic isolated DVT enrolled in the national ( France ) , multicenter , prospect i ve OPTIMEV study . This sub- study outcomes were recurrent venous thromboembolism , major bleeding and death at three months . Among the 6141 patients with suspicion of isolated DVT included between November 2004 and January 2006 , DVT was confirmed in 1643 patients ( 26.8 % ) . Isolated distal DVT was more frequent than proximal DVT ( 56.8 % vs. 43.2 % , respectively ; p = 0.01 ) . Isolated distal DVT was significantly more often associated with transient risk factors ( recent surgery , recent plaster immobilisation , recent travel ) , whereas proximal DVT was significantly more associated with more chronic states ( active cancer , congestive heart failure or respiratory insufficiency , age > 75 years ) . Most patients ( 96.8 % ) with isolated distal DVT received  anticoagulant therapies .  There was no difference in the percentage of recurrent venous thromboembolism and major bleeding in patients with proximal DVT and isolated distal DVT . However , the mortality rate was significantly higher ( p < 0.01 ) in patients with proximal DVT ( 8.0 % ) than in those with isolated distal DVT ( 4.4 % ) . Symptomatic isolated distal DVT differs from symptomatic proximal DVT both in terms of risk factors and clinical outcome . Whether these differences should influence the clinical management of these two events 
    Output:
    
Anticoagulation may maximally benefit those patients with extensive and /or symptomatic disease or those with higher risk for complication ( unprovoked , cancer-associated or pregnancy )