Serial D-dimers after anticoagulant cessation in unprovoked venous thromboembolism: Data from the REVERSE cohort study.

INTRODUCTION: While several risk stratification tools have been developed to predict the risk of recurrence in patients with an unprovoked venous thromboembolism (VTE), only 1 in 4 patients are categorized as low-risk. Rather than a one-time measure, serial D-dimer assessment holds promise to enhance the prediction of VTE recurrence after oral anticoagulant (OAC) cessation. METHODS: Using the REVERSE cohort, we compared VTE recurrence among patients with normal D-dimer levels (<490 ng/mL among males under age 70, <500 ng/mL in others) at OAC cessation and 1-month follow-up, to those with an elevated D-dimer level at either timepoint. We also evaluated VTE recurrence based on absolute increase in D-dimer levels between the two timepoints (e.g., ∆D-dimer) according to quartiles. RESULTS: Among 214 patients with serial D-dimer levels measured at OAC cessation and 1-month follow-up, an elevated D-dimer level at either timepoint was associated with a numerically higher risk of recurrent VTE than patients with normal D-dimer levels at both timepoints (6.9 % vs. 4.2 % per year, hazard ratio 1.6; 95 % CI 0.9-2.7). Among women with <2 HERDOO2 criteria, a normal D-dimer level at both timepoints predicted a very low risk of recurrent VTE during follow-up (0.8 % per year, 95 % CI 0.1-2.8). Irrespective of baseline value, recurrent VTE risk was only 3 % per year (95 % CI 1.4-5.6) among patients in the lowest ∆D-dimer quartile. CONCLUSION: Serial normal D-dimer levels have the potential to identify patients at a low risk of recurrent VTE. In addition, ∆D-dimer, irrespective of its elevation above cutoff threshold, may predict recurrent VTE.

Residual pulmonary vascular obstruction and recurrence after acute pulmonary embolism: a systematic review and meta-analysis of individual participant data.

We aimed to assess the relationship between residual pulmonary vascular obstruction (RPVO) on planar lung scan after completion of at least 3 months of anticoagulant therapy for acute pulmonary embolism (PE) and the risk of recurrent venous thromboembolism (VTE) or death due to PE one year after treatment discontinuation. The systematic review was registered with the International Prospective Registry of Systematic Reviews (PROSPERO: CRD42017081080). The primary outcome measure was to generate a pooled estimate of the rate of recurrent VTE at one year in patient with RPVO diagnosed on planar lung scan after discontinuation of at least 3 months of anticoagulant treatment for an acute PE. Individual data were obtained for 809 patients. RPVO (ie, obstruction >0%) was found in 407 patients (50.3%) after a median of 6.6 months of anticoagulant therapy for a first acute PE. Recurrent VTE or death due to PE occurred in 114 patients (14.1%), for an annual risk of 6.4% (95% confidence interval, 4.7%-8.6%). Out of the 114 recurrent events, 63 occurred within one year after discontinuation of anticoagulant therapy corresponding to a risk of 8.1% (6.4%-9.8%) at 1 year. The risk of recurrent VTE at one year was 5.8% (4.4-7.2) in participants with RPVO <5%, vs 11.7% (9.5-13.8) in participants with RPVO ≥5%. RPVO is a significant predictor of the risk of recurrent venous thromboembolism. However, the risk of recurrent events remains too high in patients without residual perfusion defect for it to be used as a stand-alone test to decide on anticoagulation discontinuation.

Performance and Head-to-Head Comparison of Three Clinical Models to Predict Occurrence of Postthrombotic Syndrome: A Validation Study.

OBJECTIVE: The SOX-PTS, Amin, and Méan models are three different clinical prediction scores stratifying the risk for postthrombotic syndrome (PTS) development in patients with acute deep vein thrombosis (DVT) of the lower limbs. Herein, we aimed to assess and compare these scores in the same cohort of patients. METHODS: We retrospectively applied the three scores in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot trial for an acute DVT. Patients were stratified into PTS risk groups using positivity thresholds for high-risk patients as proposed in the derivation studies. All patients were assessed for PTS 6 months after index DVT using the Villalta scale. We calculated the predictive accuracy for PTS and area under receiver operating characteristic (AUROC) curve for each model. RESULTS: The Méan model was the most sensitive (sensitivity 87.7%; 95% confidence interval [CI]: 77.2-94.5) with the highest negative predictive value (87.5%; 95% CI: 76.8-94.4) for PTS. The SOX-PTS was the most specific score (specificity 97.5%; 95% CI: 92.7-99.5) with the highest positive predictive value (72.7%; 95% CI: 39.0-94.0). The SOX-PTS and Méan models performed well for PTS prediction (AUROC: 0.72; 95% CI: 0.65-0.80 and 0.74; 95% CI: 0.67-0.82), whereas the Amin model did not (AUROC: 0.58; 95% CI: 0.49-0.67). CONCLUSION: Our data support that the SOX-PTS and Méan models have good accuracy to stratify the risk for PTS.

The risk of major bleeding in patients with factor V Leiden or prothrombin G20210A gene mutation while on extended anticoagulant treatment for venous thromboembolism.

BACKGROUND: Thrombophilia predisposes to venous thromboembolism (VTE) because of acquired or hereditary factors. Among them, it has been suggested that gene mutations of the factor V Leiden (FVL) or prothrombin G20210A mutation (PGM) might reduce the risk of bleeding, but little data exist for patients treated using anticoagulants. OBJECTIVES: To assess whether thrombophilia is protective against bleeding. METHODS: This multicentre, multinational, prospective cohort study evaluated adults receiving long-term anticoagulants after a VTE event. We analyzed the incidence of major bleeding as the primary outcome, according to the genotype for FVL and PGM (wild-type and heterozygous/homozygous carriers). RESULTS: Of 2260 patients with genotype testing, during a median follow-up of 3 years, 106 patients experienced a major bleeding event (17 intracranial and 7 fatal). Among 439 carriers of FVL, 19 experienced major bleeding and there were no differences between any mutation vs wild-type (hazard ratio [HR], 0.89 [0.53-1.49]; p = .66). The comparison of major bleeding events between the 158 patients with any-PGM mutation (heterozygous or homozygous) vs wild-type also showed a nonstatistically significant difference with HR of 0.53 (0.19-1.43), p = .21. However, multivariate analysis demonstrated that major bleeds or clinically relevant nonmajor bleeding were statistically less likely for patients with either FVL and/or PGM compared with patients with both wild-type factor V and prothrombin genes (HR, 0.73; 95% CI = 0.55-0.97; p = .03). CONCLUSION: This study demonstrates that thrombophilia, defined as the presence of either FVL or the prothrombin G20210A mutation, is related with a lower rate of major/clinically relevant nonmajor bleeding while on anticoagulants in the extended treatment for VTE.

Postthrombotic syndrome and quality of life after deep vein thrombosis in patients treated with edoxaban versus warfarin.

Background: Postthrombotic syndrome (PTS) is a long-term complication after deep vein thrombosis (DVT) and can affect quality of life (QoL). Pathogenesis is not fully understood but inadequate anticoagulant therapy with vitamin K antagonists is a known risk factor for the development of PTS. Objectives: To compare the prevalence of PTS after acute DVT and the long-term QoL following DVT between patients treated with edoxaban or warfarin. Methods: We performed a long-term follow-up study in a subset of patients with DVT who participated in the Hokusai-VTE trial between 2010 and 2012 (NCT00986154). Primary outcome was the prevalence of PTS, defined by the Villalta score. The secondary outcome was QoL, assessed by validated disease-specific (VEINES-QOL) and generic health-related (SF-36) questionnaires. Results: Between 2017 and 2020, 316 patients were enrolled in 26 centers in eight countries, of which 168 (53%) patients had been assigned to edoxaban and 148 (47%) to warfarin during the Hokusai-VTE trial. Clinical, demographic, and thrombus-specific characteristics were comparable for both groups. Mean (SD) time since randomization in the Hokusai-VTE trial was 7.0 (1.0) years. PTS was diagnosed in 85 (51%) patients treated with edoxaban and 62 (42%) patients treated with warfarin (adjusted odds ratio 1.6, 95% CI 1.0-2.6). Mean differences in QoL scores between treatment groups were not clinically relevant. Conclusion: Contrary to our hypothesis, the prevalence of PTS tended to be higher in patients treated with edoxaban compared with warfarin. No differences in QoL were observed. Further research is warranted to unravel the role of anticoagulant therapy on development of PTS.

Predicting major bleeding during extended anticoagulation for unprovoked or weakly provoked venous thromboembolism.

No clinical prediction model has been specifically developed or validated to identify patients with unprovoked venous thromboembolism (VTE) who are at high risk of major bleeding during extended anticoagulation. In a prospective multinational cohort study of patients with unprovoked VTE receiving extended anticoagulation after completing ≥3 months of initial treatment, we derived a new clinical prediction model using a multivariable Cox regression model based on 22 prespecified candidate predictors for the primary outcome of major bleeding. This model was then compared with modified versions of 5 existing clinical scores. A total of 118 major bleeding events occurred in 2516 patients (annual risk, 1.7%; 95% confidence interval [CI], 1.4-2.1). The incidences of major bleeding events per 100 person-years in high-risk and non-high-risk patients, respectively, were 3.9 (95% CI, 3.0-5.1) and 1.1 (0.8-1.4) using the newly derived creatinine, hemoglobin, age, and use of antiplatelet agent (CHAP) model; 3.3 (2.6-4.1) and 1.0 (0.7-1.3) using modified ACCP score, 5.3 (0.6-19.2) and 1.7 (1.4-2.0) using modified RIETE score, 3.1 (2.3-3.9) and 1.1 (0.9-1.5) using modified VTE-BLEED score, 5.2 (3.3-7.8) and 1.5 (1.2-1.8) using modified HAS-BLED score, and 4.8 (1.3-12.4) and 1.7 (1.4-2.0) using modified outpatient bleeding index score. Modified versions of the ACCP, VTE-BLEED, and HAS-BLED scores help identify patients with unprovoked VTE who are at high risk of major bleeding and should be considered for discontinuation of anticoagulation after 3 to 6 months of initial treatment. The CHAP model may further improve estimation of bleeding risk by using continuous predictor variables, but external validation is required before its implementation in clinical practice.

Prevention of post-thrombotic syndrome with rosuvastatin: A multicenter randomized controlled pilot trial (SAVER).

BACKGROUND: Post-thrombotic syndrome (PTS) is one of the most frequent complications of venous thromboembolism (VTE) leading to considerable morbidity and cost. Apart from appropriate anticoagulation, there is no drug or medical intervention that helps to prevent PTS. We conducted a multicenter randomized controlled trial to determine whether rosuvastatin can prevent PTS. METHODS: 312 patients receiving standard anticoagulation for a newly diagnosed VTE were randomly allocated to adjuvant rosuvastatin 20 mg once daily for 180 days (n = 155) or no rosuvastatin (n = 157). At the last study visit (Day 180 ± 21), an independent observer who was blinded to study treatment performed a PTS assessment using the Villalta scale. The primary clinical outcome of the trial was mean Villalta score at Day 180. We also explored the presence of PTS as defined by Villalta score > 4 at Day 180. Patients mean age was 46.7 ± 10.8 years, 55.8% were female. RESULTS: At Day 180, the Villalta score was 3.5 ± 0.3 in the rosuvastatin arm vs. 3.3 ± 0.3 in the control arm (p = 0.59), and presence of PTS (Villalta >4) was 29.7% in the rosuvastatin arm vs. 25.5% in the control arm (p = 0.41). Secondary analyses showed no difference between trial arms for presence of severe PTS at Day 180 (2.0% vs. 2.7%, p = 1) and for changes in Villalta score between baseline and Day 180 (-3.7 ± 4.4 vs. -4.0 ± 5.0, p = 0.59). CONCLUSION: This randomized controlled pilot trial did not demonstrate efficacy of rosuvastatin to reduce Villalta score. Further studies with longer duration of exposure to rosuvastatin are needed. TRIAL REGISTRATION: ClinicalTrials.gov, number NCT02679664.

External Validation of the Patient-Reported Villalta Scale for the Diagnosis of Postthrombotic Syndrome.

INTRODUCTION: The Villalta scale is the endorsed tool to diagnose and grade the severity of postthrombotic syndrome (PTS); however, assessing presence and severity of PTS is time-consuming and relies on both the clinician and patient's assessments. The patient-reported Villalta scale version 2 (PRV2) is a visually assisted form that enables patients to self-assess presence and severity of PTS. Herein, we report on external validation of this tool. METHODS: We assessed the agreement and kappa values of PRV2 to diagnose and assess severity of PTS compared with the original Villalta score in a cohort of 181 patients (196 limbs) who participated in the SAVER pilot randomized control trial. Presence of PTS was defined as PRV2 ≥5 or a Villalta score ≥5. RESULTS: PTS prevalence was 42% using PRV2 and 33% using the Villalta scale. The corresponding kappa and percentage agreement were 0.60 (95% confidence interval [CI]: 0.49-0.71) and 81% (95% CI: 76-87), respectively. Kappa values and percentage agreements between PRV2 and Villalta scale increased with increasing severity of PTS. The sensitivity of PRV2 to detect PTS of any severity was 84% (95% CI: 73-92) with a specificity of 79% (95% CI: 71-86). CONCLUSION: We conclude that the PRV2 is an acceptable tool for diagnosing and grading the severity of PTS.

Statins for venous event reduction in patients with venous thromboembolism: A multicenter randomized controlled pilot trial assessing feasibility.

BACKGROUND: Statins may reduce the risk for recurrent venous thromboembolism (VTE); however, no randomized trials have explored this hypothesis. We performed a pilot randomized trial to determine feasibility of recruitment for a larger trial of secondary VTE prevention with rosuvastatin. METHODS: Patients with a newly diagnosed symptomatic proximal deep vein thrombosis and/or pulmonary embolism, receiving standard anticoagulation, were randomly allocated to adjuvant rosuvastatin 20 mg once daily for 180 days or no rosuvastatin for 6 months. RESULTS: Between November 2016 and December 2019, 3391 patients were assessed for eligibility in six centers. Of these patients, 1347 (39.7%) were eligible and approached for participation in the trial and 312 (23.1%) were randomized. The mean rate of randomization was 8.2 ± 4.3 patients per month. During follow-up, five recurrent VTE events were observed, three (1.9%) in the rosuvastatin group (two pulmonary embolism, one deep vein thrombosis), and two (1.3%) in the control group (two pulmonary embolism; P = 0.68). One major arterial event occurred in the rosuvastatin arm and none in the control arm (0.6% vs. 0%, P = 0.50). CONCLUSION: This pilot trial supports the feasibility of a larger scale randomized controlled trial to determine the efficacy of adjuvant rosuvastatin for the secondary prevention of VTE.

Risk for Recurrent Venous Thromboembolism in Patients With Subsegmental Pulmonary Embolism Managed Without Anticoagulation : A Multicenter Prospective Cohort Study.

BACKGROUND: The incidence of pulmonary embolism has been increasing, but its case-fatality rate is decreasing, suggesting a lesser severity of illness. The clinical importance of patients with pulmonary embolism isolated to the subsegmental vessels is unknown. OBJECTIVE: To determine the rate of recurrent venous thromboembolism in patients with subsegmental pulmonary embolism managed without anticoagulation. DESIGN: Multicenter prospective cohort study. (ClinicalTrials.gov: NCT01455818). SETTING: Eighteen sites between February 2011 and February 2021. PATIENTS: Patients with isolated subsegmental pulmonary embolism. INTERVENTION: At diagnosis, patients underwent bilateral lower-extremity venous ultrasonography, which was repeated 1 week later if results were negative. Patients without deep venous thrombosis did not receive anticoagulant therapy. MEASUREMENTS: The primary outcome was recurrent venous thromboembolism during the 90-day follow-up period. RESULTS: Recruitment was stopped prematurely because the predefined stopping rule was met after 292 of a projected 300 patients were enrolled. Of the 266 patients included in the primary analysis, the primary outcome occurred in 8 patients, for a cumulative incidence of 3.1% (95% CI, 1.6% to 6.1%) over the 90-day follow-up. The incidence of recurrent venous thromboembolism was 2.1% (CI, 0.8% to 5.5%) and 5.7% (CI, 2.2% to 14.4%) over the 90-day follow-up in patients with single and multiple isolated subsegmental pulmonary embolism, respectively. No patients had a fatal recurrent pulmonary embolism. LIMITATION: The study was restricted to patients with low-risk subsegmental pulmonary embolism. CONCLUSION: Overall, patients with subsegmental pulmonary embolism who did not have proximal deep venous thrombosis had a higher-than-expected rate of recurrent venous thromboembolism. PRIMARY FUNDING SOURCE: Heart and Stroke Foundation of Canada and French Ministry of Health Programme Hospitalier de Recherche Clinique.

Quality of life in patients with pulmonary embolism treated with edoxaban versus warfarin.

BACKGROUND: Long-term sequelae of acute pulmonary embolism (PE) include decreased quality of life (QoL). Evidence suggests that adequacy of initial anticoagulant treatment in the acute phase of venous thrombosis has a key impact on late postthrombotic complications. We hypothesize that patients with acute PE treated with edoxaban for acute PE experience have improved QoL compared to those treated with warfarin. METHODS: Patients with PE who participated in the Hokusai-VTE trial were contacted between June 2017 and September 2020 for a single long-term follow-up visit. Main outcomes were the generic and disease-specific QoL measured by the 36-Item Short Form Health Survey (SF-36) and Pulmonary Embolism Quality of Life questionnaire. RESULTS: We included 251 patients from 26 centers in eight countries, of which 129 (51%) had been assigned to edoxaban and 122 (49%) to warfarin. Patient- and thrombus-specific characteristics were similar in both groups. Mean time since randomization in the Hokusai-VTE trial was 7.0 years (standard deviation, 1.0). No relevant or statistical differences were observed in the QoL for patients treated with edoxaban compared to patients treated with warfarin. The mean difference between patients treated with edoxaban and patients with PE treated with warfarin was 0.8 (95% confidence interval [CI]. -1.6 to 3.2) for the SF-36 summary mental score and 1.6 (95% CI, -0.9 to 4.1) for summary physical score. CONCLUSION: Our findings indicate that patients with an index PE treated with edoxaban or warfarin have a similar long-term QoL. Since our study was a follow-up study from a well-controlled clinical trial setting, future studies should be designed in a daily clinical practice setting. We suggest a longitudinal design for investigation of changes in QoL over time.

Postoperative low molecular weight heparin bridging treatment for patients at high risk of arterial thromboembolism (PERIOP2): double blind randomised controlled trial.

OBJECTIVE: To determine the efficacy and safety of dalteparin postoperative bridging treatment versus placebo for patients with atrial fibrillation or mechanical heart valves when warfarin is temporarily interrupted for a planned procedure. DESIGN: Prospective, double blind, randomised controlled trial. SETTING: 10 thrombosis research sites in Canada and India between February 2007 and March 2016. PARTICIPANTS: 1471 patients aged 18 years or older with atrial fibrillation or mechanical heart valves who required temporary interruption of warfarin for a procedure. INTERVENTION: Random assignment to dalteparin (n=821; one patient withdrew consent immediately after randomisation) or placebo (n=650) after the procedure. MAIN OUTCOME MEASURES: Major thromboembolism (stroke, transient ischaemic attack, proximal deep vein thrombosis, pulmonary embolism, myocardial infarction, peripheral embolism, or vascular death) and major bleeding according to the International Society on Thrombosis and Haemostasis criteria within 90 days of the procedure. RESULTS: The rate of major thromboembolism within 90 days was 1.2% (eight events in 650 patients) for placebo and 1.0% (eight events in 820 patients) for dalteparin (P=0.64, risk difference -0.3%, 95% confidence interval -1.3 to 0.8). The rate of major bleeding was 2.0% (13 events in 650 patients) for placebo and 1.3% (11 events in 820 patients) for dalteparin (P=0.32, risk difference -0.7, 95% confidence interval -2.0 to 0.7). The results were consistent for the atrial fibrillation and mechanical heart valves groups. CONCLUSIONS: In patients with atrial fibrillation or mechanical heart valves who had warfarin interrupted for a procedure, no significant benefit was found for postoperative dalteparin bridging to prevent major thromboembolism. TRIAL REGISTRATION: Clinicaltrials.gov NCT00432796.

Splanchnic vein thrombosis: Clinical manifestations, risk factors, management, and outcomes.

BACKGROUND: Clinical manifestations and optimal management strategies in patients with splanchnic vein thrombosis (SVT) are not well characterized. METHODS: We conducted a retrospective cohort study including all newly diagnosed SVT evaluated between January 2007 and December 2018. Efficacy outcome was thrombosis resolution, and safety outcomes included death and occurrence of bleeding. RESULTS: We included 155 patients with a mean age of 56.2 (18-87). Local risk factors were present in 118 (76.1%) patients and 30 (19.4%) had only systemic/thrombophilia. Local risk factors included abdominal cancers (31%), surgery (20.6%) and liver cirrhosis (19.4%). Thrombophilia screening was conducted in approximately 50% of patients. Factor V Leiden or Prothrombin G20210A mutations were observed in 7.1% of patients whereas 14.4% were JAK2V617F mutation positive. Most common manifestations at onset were abdominal pain (56.1%), whereas 44.6% were incidentally found. Portal vein thrombosis was observed more in primary cases (91.9% vs. 69.5%, p = 0.012). Anticoagulation was used in 93.5% cases. Indefinite anticoagulation was used more frequently in primary SVT (62.2% vs. 41.5%, p = 0.045). Thrombosis resolution and bleeding complications among primary (without local risk factors) and secondary (with local risk factors) SVT were observed in 48.5%, 65%, 8.1%, and 11.9%, respectively with no difference when comparing patients treated with direct oral anticoagulants or warfarin and/or low molecular weight heparin (58% vs. 62%, p = 0.326, 9% vs. 12%, p = 0.518). CONCLUSIONS: In this cohort anticoagulation resulted in partial or complete thrombosis resolution in a significant proportion of patients with an acceptable bleeding risk regardless local risk factors or type of anticoagulant.

Long-term risk of recurrent venous thromboembolism after a first contraceptive-related event: Data from REVERSE cohort study.

INTRODUCTION: The risk of recurrent venous thromboembolism (VTE) after combined oral contraceptive (COC) use is variably reported. We assessed the long-term risk of recurrent VTE in women on COC at the time of a first VTE, in comparison to women without COC use. Our secondary aim assessed the impact of COC use on the recurrent VTE risk in high-risk and low-risk hyperpigmentation, edema, or redness in either leg; D-dimer level ≥250 µg/L; obesity with body mass index ≥30; or older age, ≥65 years (HERDOO2) subgroups. METHODS: The REVERSE cohort study derived the HERDOO2 clinical decision rule to predict recurrent VTE in patients who discontinued anticoagulation after 5-7 months for a first unprovoked VTE. Incidence rates of recurrent VTE among women with and without COC exposure were calculated as the number of recurrent VTE over the number of person-years of follow-up, and Cox proportional hazards model was used to compare risks between groups. RESULTS: The risk of recurrent VTE among COC users was 1.1% (95% confidence interval [CI] 0.3-2.9) per patient-year as compared with 3.2% per patient-year (95% CI 2.4-4.3) among nonusers (hazard ratio 0.37; 95% CI 0.1-1.0). Women who were COC users and high risk by HERDOO2 score had a recurrence rate of 3.5% (95% CI 0.4-12.5) compared with 6.1% (95% CI 4.3-8.5) among women who were non-COC users and at high risk by HERDOO2 score (HR 0.6, 95% CI 0.1-2.5). CONCLUSIONS: Women who were COC users at the time of an otherwise unprovoked VTE event had a lower VTE recurrence rate during long-term follow-up, compared with nonusers. The use of HERDOO2 rule may help identify higher risk women with COC use.

Yield of ultrasonography in patients with or without post-thrombotic syndrome for diagnosis of suspected recurrent ipsilateral deep vein thrombosis.

BACKGROUND: The yield of ultrasonography in patients with or without post-thrombotic syndrome (PTS) presenting with a suspected recurrent ipsilateral deep vein thrombosis (DVT) is unknown. METHODS: Patients with a first unprovoked DVT received standard anticoagulation for 5 to 7 months. Then, they were assessed for PTS using the Villalta scale (score equal or >5) and followed for up to 18 months. Yield of ultrasonography for recurrent ipsilateral DVT was defined as the number of confirmed DVT divided by the number of suspicions. Outcomes were compared between patients without or with PTS. RESULTS AND DISCUSSION: A total of 452 patients with a symptomatic proximal DVT were included. During follow-up, there were 144 suspicions of recurrent ipsilateral DVT, which were confirmed in 38 patients (26.4%). The confirmation rate of recurrent ipsilateral DVT was 25.6% (23/90) in patients without PTS as compared with 27.8% (15/54) in patients with PTS (P = .84). Our study supports a similar yield of ultrasonography to diagnose recurrent ipsilateral DVT in patients off anticoagulation therapy with or without PTS as defined by 5 or more points on the Villalta scale.