Marie-José Miron

Determinants and Time Course of the Postthrombotic Syndrome after Acute Deep Venous Thrombosis

BACKGROUND The reason some patients with deep venous thrombosis (DVT) develop the postthrombotic syndrome is not well understood. OBJECTIVE To determine the frequency, time course, and predictors of the postthrombotic syndrome after acute DVT. DESIGN Prospective, multicenter cohort study. SETTING 8 Canadian hospital centers. PATIENTS 387 outpatients and inpatients who received an objective diagnosis of acute symptomatic DVT were recruited from 2001 to 2004. MEASUREMENTS Standardized assessments for the postthrombotic syndrome using the Villalta scale at 1, 4, 8, 12, and 24 months after enrollment. Mean postthrombotic score and severity category at each interval was calculated. Predictors of postthrombotic score profiles over time since diagnosis of DVT were identified by using linear mixed modeling. RESULTS At all study intervals, about 30% of patients had mild (score, 5 to 9), 10% had moderate (score, 10 to 14), and 3% had severe (score >14 or ulcer) postthrombotic syndrome. Greater postthrombotic severity category at the 1-month visit strongly predicted higher mean postthrombotic scores throughout 24 months of follow-up (1.97, 5.03, and 7.00 increase in Villalta score for mild, moderate, and severe 1-month severity categories, respectively, vs. none; P < 0.001). Additional predictors of higher scores over time were venous thrombosis of the common femoral or iliac vein (2.23 increase in score vs. distal [calf] venous thrombosis; P < 0.001), higher body mass index (0.14 increase in score per kg/m(2); P < 0.001), previous ipsilateral venous thrombosis (1.78 increase in score; P = 0.001), older age (0.30 increase in score per 10-year age increase; P = 0.011), and female sex (0.79 increase in score; P = 0.020). LIMITATIONS Decisions to prescribe compression stockings were left to treating physicians rather than by protocol. Because international normalized ratio data were unavailable, the relationship between anticoagulation quality and Villalta scores could not be assessed. CONCLUSION The postthrombotic syndrome occurs frequently after DVT. Patients with extensive DVT and those with more severe postthrombotic manifestations 1 month after DVT have poorer long-term outcomes.

Determinants of health-related quality of life during the 2 years following deep vein thrombosis.

Summary.  Background/objectives: We prospectively measured change in quality of life (QOL) during the 2 years after a diagnosis of deep vein thrombosis (DVT) and evaluated determinants of QOL, including development of the post‐thrombotic syndrome (PTS). Patients/methods: Consecutive patients with acute DVT were recruited from 2001 to 2004 at eight hospitals in Canada. At study visits at baseline, and 1, 4, 8, 12 and 24 months, clinical data were collected, standardized PTS assessments were performed, and QOL questionnaires were self‐completed. Generic QOL was measured using the Short‐Form Health Survey‐36 (SF‐36) questionnaire. Venous disease‐specific QOL was measured using the Venous Insufficiency Epidemiological and Economic Study (VEINES)‐QOL/Sym questionnaire. The change in QOL scores over a 2‐year follow‐up was assessed. The influence of PTS and other characteristics on QOL at 2 years was evaluated using multivariable regression analyses. Results: Among the 387 patients recruited, the average age was 56 years, two‐thirds were outpatients, and 60% had proximal DVT. The cumulative incidence of PTS was 47%. On average, QOL scores improved during follow‐up. However, patients who developed PTS had lower scores at all visits and significantly less improvement in QOL over time (P‐values for PTS*time interaction were 0.001, 0.012, 0.014 and 0.006 for PCS, MCS, VEINES‐QOL and VEINES‐Sym). Multivariable regression analyses showed that PTS (P < 0.0001), age (P = 0.0009), proximal DVT (P = 0.01) and inpatient status (P = 0.04) independently predicted 2‐year SF‐36 PCS scores. PTS alone independently predicted 2‐year VEINES‐QOL (P < 0.0001) and VEINES‐Sym (P < 0.0001) scores. Conclusions: Development of PTS is the principal determinant of health‐related QOL 2 years after DVT. Our study provides prognostic information on patient‐reported outcomes after DVT and emphasizes the need for effective prevention and treatment of the PTS.

Compression stockings to prevent post-thrombotic syndrome: a randomised placebo-controlled trial.

BACKGROUND Post-thrombotic syndrome (PTS) is a common and burdensome complication of deep venous thrombosis (DVT). Previous trials suggesting benefit of elastic compression stockings (ECS) to prevent PTS were small, single-centre studies without placebo control. We aimed to assess the efficacy of ECS, compared with placebo stockings, for the prevention of PTS. METHODS We did a multicentre randomised placebo-controlled trial of active versus placebo ECS used for 2 years to prevent PTS after a first proximal DVT in centres in Canada and the USA. Patients were randomly assigned to study groups with a web-based randomisation system. Patients presenting with a first symptomatic, proximal DVT were potentially eligible to participate. They were excluded if the use of compression stockings was contraindicated, they had an expected lifespan of less than 6 months, geographical inaccessibility precluded return for follow-up visits, they were unable to apply stockings, or they received thrombolytic therapy for the initial treatment of acute DVT. The primary outcome was PTS diagnosed at 6 months or later using Ginsbergs criteria (leg pain and swelling of ≥1 month duration). We used a modified intention to treat Cox regression analysis, supplemented by a prespecified per-protocol analysis of patients who reported frequent use of their allocated treatment. This study is registered with ClinicalTrials.gov, number NCT00143598, and Current Controlled Trials, number ISRCTN71334751. FINDINGS From 2004 to 2010, 410 patients were randomly assigned to receive active ECS and 396 placebo ECS. The cumulative incidence of PTS was 14·2% in active ECS versus 12·7% in placebo ECS (hazard ratio adjusted for centre 1·13, 95% CI 0·73-1·76; p=0·58). Results were similar in a prespecified per-protocol analysis of patients who reported frequent use of stockings. INTERPRETATION ECS did not prevent PTS after a first proximal DVT, hence our findings do not support routine wearing of ECS after DVT. FUNDING Canadian Institutes of Health Research.

Economic burden and cost determinants of deep vein thrombosis during 2 years following diagnosis: a prospective evaluation

Summary.  Background: Few studies have evaluated the long‐term economic consequences of deep vein thrombosis (DVT). None of them have incorporated prospectively collected clinical data to ensure accurate identification of incident cases of DVT and DVT‐related health outcomes of interest, such as post‐thrombotic syndrome (PTS). Objectives: To prospectively quantify medical and non‐medical resource use and costs related to DVT during 2 years following diagnosis, and to identify clinical determinants of costs. Methods: Three hundred and fifty‐five consecutive patients with acute DVT were recruited at seven Canadian hospital centers. Resource use and cost information were retrieved from three sources: weekly patient‐completed cost diaries, nurse‐completed case report forms, and the Quebec provincial administrative healthcare database (RAMQ). Results: The rate of DVT‐related hospitalization was 3.5 per 100 patient‐years (95% confidence interval [CI] 2.2–4.9). Patients reported a mean (standard deviation) of 15.0 (14.5) physician visits and 0.7 (1.2) other healthcare professional visits. The average cost of DVT was

Relation between D‐dimer level, venous valvular reflux and the development of post‐thrombotic syndrome after deep vein thrombosis

5180 (95% CI

Management and adherence to VTE treatment guidelines in a national prospective cohort study in the Canadian outpatient setting. The Recovery Study.

4344–6017) in Canadian dollars, with 51.6% of costs being attributable to non‐medical resource use. Multivariate analysis identified four independent predictors of costs: concomitant pulmonary embolism (relative increase in cost [RIC] 3.16; 95% CI 2.18–4.58), unprovoked DVT (RIC 1.65; 95% CI 1.28–2.13), development of PTS during follow‐up (RIC 1.35; 95% CI 1.05–1.74), and management of DVT in the inpatient setting (RIC 1.79; 95% CI 1.33–2.40). Conclusions: The economic burden of DVT is substantial. The use of measures to prevent the occurrence of PTS and favoring outpatient care of DVT has the potential to diminish costs.

Graduated compression stockings to treat acute leg pain associated with proximal DVT. A randomised controlled trial.

Summary.  Background: The pathophysiology of post‐thrombotic syndrome (PTS) is postulated to involve persistent venous obstruction and venous valvular reflux. Objective: To study the association between D‐dimer level, valvular reflux and the PTS in a well‐defined cohort of deep vein thrombosis (DVT) patients. Methods: Consecutive patients with acute symptomatic DVT were recruited at eight centers and were followed for 24 months. D‐dimer was measured at 4 months. A standardized ultrasound assessment for popliteal valvular reflux was performed at 12 months. Using the Villalta scale, patients were assessed for PTS during follow‐up by evaluators who were unaware of D‐dimer or reflux results. Results: Three hundred and eighty‐seven patients were recruited; of these, 305 provided blood samples for D‐dimer and 233 had a 12‐month reflux assessment. PTS developed in 45.1% of subjects. Mean D‐dimer was significantly higher in patients with vs. without PTS (712.0 vs. 444.0 μg L−1; P = 0.02). In logistic regression analyses adjusted for warfarin use at the time of D‐dimer determination and risk factors for PTS, D‐dimer level significantly predicted PTS (P = 0.03); when stratifying for warfarin use at the time of blood draw, adjusted odds ratio (OR) for developing PTS per unit difference in log D‐dimer was 2.33 (95% CI 0.89, 6.10) in those not on warfarin vs. 1.25 (95% CI 0.87, 1.79) in those on warfarin. Ipsilateral reflux was more frequent in patients with moderate‐to‐severe PTS than in patients with mild PTS (65% vs. 40%, respectively; P = 0.01) and was independently associated with moderate‐to‐severe PTS in logistic regression analyses (P = 0.01). Conclusion: D‐dimer levels, measured 4 months after DVT in patients not on warfarin, are associated with subsequent development of PTS. Venous valvular reflux is associated with moderate‐to‐severe PTS.

Inflammation markers and their trajectories after deep vein thrombosis in relation to risk of post-thrombotic syndrome

Documenting patterns and outcomes of venous thromboembolism (VTE) management and degree of adherence by clinicians to treatment guidelines could help identify remediable gaps in patient care. Prospective, clinical practice-based data from Canadian outpatient settings on management of VTE, degree of adherence with treatment guidelines and frequency of recurrent VTE and bleeding during follow-up was obtained in a multicentre, prospective observational study. From 12 Canadian centres, we assessed 868 outpatients with acute symptomatic VTE who received the low-molecular-weight heparin (LMWH) enoxaparin alone or with vitamin K antagonists (VKA), at baseline and at six months (or at the end of treatment, whichever came first). Index VTE was limb deep venous thrombosis (DVT) in 583 (67.2%) patients, pulmonary embolism (PE) with or without DVT in 262 (30.2%) patients, and unusual site DVT in 23 (2.6%) patients. VTE was unprovoked in 399 (46.0%) patients, associated with cancer in 74 (8.5%) patients, transient risk factors in 327 (37.7%) patients and hormonal factors in 68 (7.8%) patients.With regard to guideline adherence, 58 (7.3%) patients received <5 days LMWH and 114 (14.5%) had overlap <1 day. Among patients with cancer-related VTE, 59.5% were prescribed LMWH monotherapy and 43.2% received such treatment for >3 months. Only 38.1% of patients with transient VTE risk factors had received thromboprophylaxis. Our study provides useful information on clinical presentation, management and related outcomes in Canadian outpatients with VTE. Our results suggest there may be important gaps in use of thromboprophylaxis to prevent VTE and use of LMWH monotherapy to treat cancer-related VTE.

Monoamines in the nervous system of the tube-wormChaetopterus variopedatus (Polychaeta): Biochemical detection and serotonin immunoreactivity

Acute deep venous thrombosis (DVT) causes leg pain. Elastic compression stockings (ECS) have potential to relieve DVT-related leg pain by diminishing the diameter of distended veins and increasing venous blood flow. It was our objective to determine whether ECS reduce leg pain in patients with acute DVT. We performed a secondary analysis of the SOX Trial, a multicentre randomised placebo controlled trial of active ECS versus placebo ECS to prevent the post-thrombotic syndrome.The study was performed in 24 hospital centres in Canada and the U.S. and included 803 patients with a first episode of acute proximal DVT. Patients were randomised to receive active ECS (knee length, 30-40 mm Hg graduated pressure) or placebo ECS (manufactured to look identical to active ECS, but lacking therapeutic compression). Study outcome was leg pain severity assessed on an 11-point numerical pain rating scale (0, no pain; 10, worst possible pain) at baseline, 14, 30 and 60 days after randomisation. Mean age was 55 years and 60% were male. In active ECS patients (n=409), mean (SD) pain severity at baseline and at 60 days were 5.18 (3.29) and 1.39 (2.19), respectively, and in placebo ECS patients (n=394) were 5.38 (3.29) and 1.13 (1.86), respectively. There were no significant differences in pain scores between groups at any assessment point, and no evidence for subgroup interaction by age, sex or anatomical extent of DVT. Results were similar in an analysis restricted to patients who reported wearing stockings every day. In conclusion, ECS do not reduce leg pain in patients with acute proximal DVT.

Immunohistochemical and radioautographic evidence of monoamine-containing cells in bioluminescent elytra of the scale-worm Harmothoe imbricata (Polychaeta)

Post‐thrombotic syndrome (PTS) is a frequent chronic complication of deep vein thrombosis (DVT).