Epidemiology of first and recurrent venous thromboembolism: a population-based cohort study in patients without active cancer

Contemporary data from population studies on the incidence and complications of venous thromboembolism (VTE) are limited. An observational cohort study was undertaken to estimate the incidence of first and recurrent VTE. The cohort was identified from all patients in the UK Clinical Practice Research Datalink (CPRD) with additional linked information on hospitalisation and cause of death. Between 2001 and 2011, patients with first VTE were identified and the subset without active cancer-related VTE observed for up to 10 years for recurrent VTE. The 10-year cumulative incidence rates (CIR) were derived with adjustment for mortality as a competing risk event. A total of 35,373 first VTE events (12,073 provoked, 16,708 unprovoked and 6592 active cancer-associated VTE) among 26.9 million person-years of observation were identified. The overall incidence rate (IR) of VTE was 131.5 (95% CI, 130.2-132.9) per 100,000 person-years and 107.0 (95% CI, 105.8-108.2) after excluding cancer-associated VTE. DVT was more common in the young and PE was more common in the elderly. VTE recurrence occurred in 3671 (CIR 25.2%). The IR for recurrence peaked in the first six months at around 11 per 100 person years. It levelled out after three years and then remained at around 2 per 100 person years from year 4-10 of follow-up. The IRs for recurrences were particularly high in young men. In conclusion, VTE is common and associated with high recurrence rates. Effort is required to prevent VTE and to reduce recurrences.

D-dimer as a predictor of venous thromboembolism in acutely ill, hospitalized patients: a subanalysis of the randomized controlled MAGELLAN trial

BACKGROUND

D-dimer concentrations have not been evaluated extensively as a predictor of increased venous thromboembolism (VTE) risk in acutely ill, hospitalized medical patients.

OBJECTIVES

To analyze the relationships between D-dimer concentration, VTE and bleeding in the MAGELLAN trial (NCT00571649).

PATIENTS/METHODS

This was a multicenter, randomized, controlled trial. Patients aged ≥ 40 years, hospitalized for acute medical illnesses with risk factors for VTE received subcutaneous enoxaparin 40 mg once daily for 10 ± 4 days then placebo up to day 35, or oral rivaroxaban 10 mg once daily for 35 ± 4 days. Patients (n = 7581) were grouped by baseline D-dimer ≤ 2 × or > 2 × the upper limit of normal. VTE and major plus non-major clinically relevant bleeding were recorded at day 10, day 35, and between days 11 and 35.

RESULTS

The frequency of VTE was 3.5-fold greater in patients with high D-dimer concentrations. Multivariate analysis showed that D-dimer was an independent predictor of the risk of VTE (odds ratio 2.29 [95% confidence interval 1.75-2.98]), and had a similar association to established risk factors for VTE, for example cancer and advanced age. In the high D-dimer group, rivaroxaban was non-inferior to enoxaparin at day 10 and, unlike the low D-dimer group, superior to placebo at day 35 (P < 0.001) and days 11-35 (P < 0.001). In both groups, bleeding outcomes favored enoxaparin/placebo.

CONCLUSIONS

Elevated baseline D-dimer concentrations may identify acutely ill, hospitalized medical patients at high risk of VTE for whom extended anticoagulant prophylaxis may provide greater benefit than for those with low D-dimer concentrations.

An adaptive-design dose-ranging study of PD 0348292, an oral factor Xa inhibitor, for thromboprophylaxis after total knee replacement surgery

BACKGROUND

PD 0348292 is an oral, selective, direct and reversible factor Xa inhibitor. This was an adaptive dose-ranging study evaluating a 100-fold PD 0348292 dose range in subjects undergoing total knee replacement (TKR).

OBJECTIVE

To assess the efficacy and safety of a dose range of PD 0348292 relative to enoxaparin for the prevention of venous thromboembolism (VTE).

METHODS

Extensive dose-response modeling and trial simulations were used to select the PD 0348292 dose range for the Phase 2 study. Subjects were randomized to a blinded PD 0348292 dose (0.1 mg qd to 10 mg qd) or open-label enoxaparin (30 mg bid) for 6-14 days after TKR surgery. Efficacy was assessed by mandatory bilateral venography. Results were analyzed using a dose-response modeling approach.

RESULTS

Observed VTE frequency ranged from 1.4-37.1% across PD 0348292 doses and was 18.1% for enoxaparin. The PD 0348292 dose-response relationship for VTE was statistically significant (P < 0.0001). The dose of PD 0348292 equivalent to enoxaparin 30 mg bid for VTE prevention was estimated to be 1.16 mg (95% CI = 0.56 mg, 2.41 mg) qd. Total bleeding ranged from 4.9% to 13.8% across PD 0348292 doses and was 6.3% with enoxaparin. The dose-response relationship for total bleeding was not statistically significant (P = 0.2464). Overall, PD 0348292 and enoxaparin were well tolerated.

CONCLUSION

Characterization of the dose-response relationship for VTE and bleeding using an adaptive Phase 2 study design provided a strong quantitative basis for Phase 3 dose selection.

Comparison of idraparinux with vitamin K antagonists for prevention of thromboembolism in patients with atrial fibrillation: a randomised, open-label, non-inferiority trial

BACKGROUND

Vitamin K antagonists, the current standard treatment for prophylaxis against stroke and systemic embolism in patients with atrial fibrillation, require regular monitoring and dose adjustment; an unmonitored, fixed-dose anticoagulant regimen would be preferable. The aim of this randomised, open-label non-inferiority trial was to compare the efficacy and safety of idraparinux with vitamin K antagonists.

METHODS

Patients with atrial fibrillation at risk for thromboembolism were randomly assigned to receive either subcutaneous idraparinux (2.5 mg weekly) or adjusted-dose vitamin K antagonists (target of an international normalised ratio of 2-3). Assessment of outcome was done blinded to treatment. The primary efficacy outcome was the cumulative incidence of all stroke and systemic embolism. The principal safety outcome was clinically relevant bleeding. Analyses were done by intention to treat; the non-inferiority hazard ratio was set at 1.5. This trial is registered with ClinicalTrials.gov, number NCT00070655.

FINDINGS

The trial was stopped after randomisation of 4576 patients (2283 to receive idraparinux, 2293 to receive vitamin K antagonists) and a mean follow-up period of 10.7 (SD 5.4) months because of excess clinically relevant bleeding with idraparinux (346 cases vs 226 cases; 19.7 vs 11.3 per 100 patient-years; p<0.0001). There were 21 instances of intracranial bleeding with idraparinux and nine with vitamin K antagonists (1.1 vs 0.4 per 100 patient-years; p=0.014); elderly patients and those with renal impairment were at greater risk of such complications. There were 18 cases of thromboembolism with idraparinux and 27 cases with vitamin K antagonists (0.9 vs 1.3 per 100 patient-years; hazard ratio 0.71, 95% CI 0.39-1.30; p=0.007), satisfying the non-inferiority criterion. There were 62 deaths with idraparinux and 61 with vitamin K anatagonists (3.2 vs 2.9 per 100 patient-years; p=0.49).

INTERPRETATION

In patients with atrial fibrillation at risk for thromboembolism, long-term treatment with idraparinux was no worse than vitamin K antagonists in terms of efficacy, but caused significantly more bleeding.

Extended prophylaxis of venous thromboembolism with idraparinux

BACKGROUND

The extended use of vitamin K antagonists for prophylaxis against venous thromboembolism is often constrained by risk-benefit limitations and inconvenience. We evaluated the efficacy and safety of a 6-month extension of prophylaxis against recurrent venous thromboembolism with idraparinux in patients who had initially received 6 months of prophylaxis with an anticoagulant.

METHODS

We randomly assigned patients who had completed 6 months of prophylaxis with idraparinux or a vitamin K antagonist and in whom extended anticoagulation was warranted to receive once-weekly injections of 2.5 mg of idraparinux or placebo for 6 months without monitoring. The primary efficacy and safety outcomes were recurrent venous thromboembolism and major bleeding.

RESULTS

Of 1215 patients, 6 of 594 (1.0%) in the idraparinux group and 23 of 621 (3.7%) in the placebo group had recurrent venous thromboembolism (P=0.002). Major bleeding occurred in 11 patients (1.9%) in the idraparinux group and in none in the placebo group (P<0.001). Of these 11 episodes, 3 were fatal intracranial hemorrhages. As compared with patients whose initial treatment was a vitamin K antagonist, patients whose initial treatment was idraparinux who were assigned to 6 months in the placebo group had a lower incidence of recurrent thromboembolism (0.7% vs. 5.9%); patients who received 6 additional months of idraparinux therapy had a higher incidence of major bleeding (3.1% vs. 0.9%).

CONCLUSIONS

During a 6-month extension of thromboprophylaxis, idraparinux was effective in preventing recurrent thromboembolism but was associated with an increased risk of a major hemorrhage. (ClinicalTrials.gov number, NCT00071279 [ClinicalTrials.gov].).

Idraparinux versus standard therapy for venous thromboembolic disease

BACKGROUND

Venous thromboembolism is treated with unfractionated heparin or low-molecular-weight heparin, followed by a vitamin K antagonist. We investigated the potential use of idraparinux, a long-acting inhibitor of activated factor X, as a substitute for standard therapy.

METHODS

We conducted two randomized, open-label noninferiority trials involving 2904 patients with deep-vein thrombosis and 2215 patients with pulmonary embolism to compare the efficacy and safety of idraparinux versus standard therapy. Patients received either subcutaneous idraparinux (2.5 mg once weekly) or a heparin followed by an adjusted-dose vitamin K antagonist for either 3 or 6 months. The primary efficacy outcome was the 3-month incidence of symptomatic recurrent venous thromboembolism (nonfatal or fatal).

RESULTS

In the study of patients with deep venous thrombosis, the incidence of recurrence at day 92 was 2.9% in the idraparinux group as compared with 3.0% in the standard-therapy group (odds ratio, 0.98; 95% confidence interval [CI], 0.63 to 1.50), a result that satisfied the prespecified noninferiority requirement. At 6 months, the hazard ratio for idraparinux was 1.01. The rates of clinically relevant bleeding at day 92 were 4.5% in the idraparinux group and 7.0% in the standard-therapy group (P=0.004). At 6 months, bleeding rates were similar. In the study of patients with pulmonary embolism, the incidence of recurrence at day 92 was 3.4% in the idraparinux group and 1.6% in the standard-therapy group (odds ratio, 2.14; 95% CI, 1.21 to 3.78), a finding that did not meet the noninferiority requirement.

CONCLUSIONS

In patients with deep venous thrombosis, once-weekly subcutaneous idraparinux for 3 or 6 months had an efficacy similar to that of heparin plus a vitamin K antagonist. However, in patients with pulmonary embolism, idraparinux was less efficacious than standard therapy. (ClinicalTrials.gov numbers, NCT00067093 [ClinicalTrials.gov] and NCT00062803 [ClinicalTrials.gov].).

The use of graduated compression stockings in association with fondaparinux in surgery of the hip

Little is known about the efficacy of graduated compression stockings in preventing venous thromboembolism after hip surgery. We conducted a prospective, randomised single-blind study to determine whether the addition of compression stockings to fondaparinux conferred any additional benefit.

The study included 874 patients, of whom 795 could be evaluated (400 in the fondaparinux group and 395 in the fondaparinux plus compression stocking group). Fondaparinux was given post-operatively for five to nine days, either alone or combined with wearing stockings, which were worn for a mean 42 days (35 to 49).

The study outcomes were venous thromboembolism, or sudden death before day 42. Duplex ultrasonography was scheduled within a week of day 42. Safety outcomes were bleeding and death from venous thromboembolism.

The prevalence of deep-vein thrombosis was similar in the two groups 5.5% (22 of 400) in the fondaparinux group and 4.8 (19 of 395) in the fondaparinux plus stocking group (odds ratio 0.88, 95% confidence interval 0.46 to 1.65, p = 0.69). Major bleeding occurred in only one patient.

The addition of graduated compression stockings to fondaparinux appears to offer no additional benefit over the use of fondaparinux alone.

Thromboprophylaxis in major abdominal surgery for cancer

AIMS

To review the epidemiology and pathogenesis of venous thromboembolism (VTE) in surgical cancer patients, in addition to the use of thromboprophylaxis in major abdominal surgery, such as low-molecular-weight heparin (LMWH) and fondaparinux.

METHODS

Systematic review of the literature, focussing on risk factors for VTE, parenteral methods of thromboprophylaxis, approaches to prolonged prophylaxis, and effects on patient survival.

FINDINGS

Patients with cancer undergoing abdominal surgery are at substantially higher risk for VTE than patients without cancer. Furthermore, prolonged thromboprophylaxis for up to 4 weeks is more effective than short-term administration in these high-risk patients. The concurrent use of graduated compression stockings has a synergistic effect on the reduction in VTE risk.

CONCLUSIONS

Thromboprophylaxis with LMWH has been shown to minimise the incidence of thromboembolic events, and is a well-established therapy worldwide. The American College of Chest Physicians recommends the routine use of thromboprophylaxis, with LMWH or unfractionated heparin, in patients with cancer who are undergoing surgical procedures, and the appropriate use of these thromboprophylactic agents has significant implications for the clinical care and quality of life of surgical patients with cancer.

Randomized clinical trial of postoperative fondaparinux versus perioperative dalteparin for prevention of venous thromboembolism in high-risk abdominal surgery

BACKGROUND

The aim of this study was to assess whether the synthetic factor Xa inhibitor fondaparinux reduced the risk of venous thromboembolism more efficiently than the low molecular weight heparin dalteparin in patients undergoing major abdominal surgery.

METHODS

In a double-blind double-dummy randomized study, patients scheduled for major abdominal surgery under general anaesthesia received once-daily subcutaneous injections of fondaparinux 2.5 mg or dalteparin 5000 units for 5-9 days. Fondaparinux was started 6 h after surgery. The first two doses of dalteparin, 2500 units each, were given 2 h before surgery and 12 h after the preoperative administration. The primary outcome measure was a composite of deep vein thrombosis detected by bilateral venography and symptomatic, confirmed deep vein thrombosis or pulmonary embolism up until day 10. The main safety outcome measure was major bleeding during treatment.

RESULTS

Among 2048 patients evaluable for efficacy, the rate of venous thromboembolism was 4.6 per cent (47 of 1027) with fondaparinux compared with 6.1 per cent (62 of 1021) with dalteparin, a relative risk reduction of 24.6 (95 per cent confidence interval -9.0 to 47.9) per cent (P = 0.144), which met the predetermined criterion for non-inferiority of fondaparinux. Major bleeding was observed in 49 (3.4 per cent) of 1433 patients given fondaparinux and 34 (2.4 per cent) of 1425 given dalteparin (P = 0.122).

CONCLUSION

Postoperative fondaparinux was at least as effective as perioperative dalteparin in patients undergoing high-risk abdominal surgery.

Meta-analysis of trials comparing ximelagatran with low molecular weight heparin for prevention of venous thromboembolism after major orthopaedic surgery

Background

Use of low molecular weight heparin (LMWH) is standard practice for preventing postoperative venous thromboembolism (VTE). Ximelagatran is a new direct thrombin inhibitor for this indication.

Methods

A systematic review was conducted to compare the efficacy and safety of LMWH with ximelagatran in orthopaedic surgery.

Results

Six eligible, well conducted clinical trials (10 051 patients) were identified. Overall, the risk of VTE (OR (odds ratio) 1·22 (95 per cent confidence interval (c.i.) 0·89 to 1·67)) and serious bleeding (OR 0·70 (95 per cent c.i. 0·42 to 1·18)) was not significantly different for LMWH compared with ximelagatran. Exploratory analyses to investigate statistical heterogeneity found that results varied by surgical subtype and treatment regimen. Compared with postoperative ximelagatran, LMWH had a significantly lower rate of VTE (OR 0·68 (95 per cent c.i. 0·56 to 0·82); P &lt; 0·001), with no significant difference in bleeding rate (OR 1·09 (95 per cent c.i. 0·62 to 1·94); P = 0·76), in hip surgery, and no significant differences in knee surgery. When ximelagatran was started immediately before surgery, LMWH had a significantly higher rate of VTE in both hip (OR 1·87 (95 per cent c.i. 1·20 to 2·92); P = 0·006) and knee (OR 1·49 (95 per cent c.i. 1·14 to 1·93); P = 0·003) surgery, but less bleeding: hip OR 0·30 (95 per cent c.i. 0·17 to 0·53; P &lt; 0·001); knee OR 0·71 (95 per cent c.i. 0·30 to 1·67; P = 0·43).

Conclusion

This review demonstrated no overall advantage for either LMWH or ximelagatran in thromboprophylaxis following orthopaedic surgery. Benefits in VTE prevention with ximelagatran were gained at the expense of an increased risk of serious bleeding.

Epidemiology of venous thromboembolism in Asian patients undergoing major orthopedic surgery without thromboprophylaxis. The SMART study

BACKGROUND

In Asian patients undergoing surgery, the incidence of venous thromboembolism (VTE) is thought to be low relative to Western patients, and the routine use of thromboprophylaxis is controversial.

OBJECTIVES

The aim of this work was to study the epidemiology of VTE in Asian patients undergoing orthopedic surgery without thromboprophylaxis.

PATIENTS AND METHODS

We performed a prospective observational study of a cohort of consecutive Asian patients hospitalized for total hip or knee replacement or hip fracture surgery without thromboprophylaxis. The primary study outcome was the incidence of the composite of symptomatic VTE or sudden death at hospital discharge. This outcome was also assessed at 1 month's follow-up.

RESULTS

Between April 2001 and July 2002, 2420 patients were enrolled. Median age was 68 years and the median duration of hospital stay was 13 days. The rate of symptomatic VTE or sudden death as notified by investigators was 2.3%[55 patients, 99% confidence interval (CI) 1.6, 3.2] and 1.2% (28 patients, 99% CI 0.7, 1.8) after adjudication by an independent committee. Chronic heart failure, varicose veins and a history of VTE were independent risk factors (P < 0.05) for the occurrence of the primary endpoint. At 1 month's follow-up, the incidence of adjudicated symptomatic VTE or sudden death was 1.5% (35/2264 patients).

CONCLUSION

In Asian patients, the incidence of symptomatic VTE after major orthopedic surgery is not low, consistent with the rates observed in Western countries. The use of thromboprophylaxis should be considered in Asian patients undergoing such high-risk surgical procedures.

Fatal pulmonary embolism in hospitalised patients: a necropsy review

AIMS

To carry out a retrospective review of all postmortem reports during the period 1991 to 2000 at King's College Hospital, London, as an extension of a previous analysis performed for the period 1965 to 1990.

METHODS

The number of deaths resulting from necropsy confirmed fatal pulmonary embolism in hospitalised patients was determined, and a limited analysis of the clinical characteristics of those patients who died was performed.

RESULTS

During the 10 year period, 16 104 deaths occurred and 6833 (42.4%) necropsies were performed. The outcome measure, fatal pulmonary embolism, was recorded as cause of death in 265 cases (3.9% of all necropsies; 5.2% of adult cases). No deaths from pulmonary embolism occurred in patients under 18 years of age; 80.0% occurred in patients older than 60 years. Of the fatal emboli, 214 of 265 (80.8%) occurred in patients who had not undergone recent surgery. Of these patients, 110 (51.4%) had suffered an acute medical illness in the six weeks before death, most often an acute infectious episode (26 cases).

CONCLUSIONS

Thromboembolic events remain a relatively common cause of death in hospitalised patients and appear to occur more frequently in non-surgical than in surgical patients.

The direct thrombin inhibitor melagatran followed by oral ximelagatran compared with enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement: the EXPRESS study

BACKGROUND

Ximelagatran and its subcutaneous (s.c.) form melagatran are novel direct thrombin inhibitors for the prevention and treatment of thromboembolic disease.

METHODS

In a double-blind study, 2835 consecutive patients undergoing total hip or knee replacement were randomized to either melagatran/ximelagatran or enoxaparin. Melagatran 2 mg was started immediately before surgery; 3 mg was then administered postoperatively, followed by 24 mg of oral ximelagatran b.i.d. beginning the next day. Enoxaparin 40 mg, administered subcutaneously o.d., was started 12 h before surgery. Both treatments were continued for 8-11 days. The main efficacy outcome measures were major venous thromboembolism (VTE); [proximal deep vein thrombosis (DVT), non-fatal and/or fatal pulmonary embolism (PE), death where PE could not be ruled out], and total VTE (proximal and distal DVT; PE; death from all causes). DVT was detected by mandatory bilateral ascending venography at the end of the treatment period or earlier if clinically suspected. The main safety outcome was bleeding.

RESULTS

The rates of major and total VTE were significantly lower in the melagatran/ximelagatran group compared with the enoxaparin group (2.3% vs. 6.3%, P = 0.0000018; and 20.3% vs. 26.6%, P < 0.0004, respectively). Fatal bleeding, critical site bleeding and bleeding requiring reoperation did not differ between the two groups. 'Excessive bleeding as judged by the investigator' was more frequent with melagatran/ximelagatran than with enoxaparin.

CONCLUSIONS

In patients undergoing total hip or knee replacement, preoperatively initiated s.c. melagatran followed by oral ximelagatran was significantly more effective in preventing VTE than preoperatively initiated s.c. enoxaparin.

Prophylaxis of venous thromboembolism in medical patients

Prophylaxis of venous thromboembolism in medical patients is an area where the potential benefits to patients are great. Venous thromboembolism is at least as common among medical as it is among surgical patients. Despite the widespread use of thromboprophylaxis in surgical patients, fatal pulmonary embolism is one of the most common causes of preventable death in the hospital. This may result from underuse of thromboprophylaxis in medical patients. The incidence of venous thromboembolism varies, but a history of previous venous thromboembolism, age 40 years and older, immobility, and specific illnesses such as stroke, myocardial infarction, heart failure, and cancer put patients at particular risk. Most early studies assessed the use of anticoagulants such as unfractionated heparin, low-molecular-weight heparin, and warfarin at reducing the incidence of venous thromboembolism in surgical patients. More recent studies and those currently being carried out are assessing the role of thromboprophylaxis in general medical patients and those with specific medical illnesses. As the evidence accumulates and guidelines are strengthened physicians will be able to tailor the use of thromboprophylaxis to the individual patient's needs.

Extended thromboprophylaxis following lower limb arthroplasty: what do the clinical trials mean?

Patients undergoing major orthopaedic surgery are at high risk of thromboembolic complications. Of the available options for pharmacologic prophylaxis, the low-molecular-weight heparins (LMWHs) have been shown to be most effective in reducing the incidence of venous thromboembolic complications and are well tolerated. However, as the risk of venous thromboembolism persists for several weeks post-discharge, there is controversy regarding the ideal duration of prophylaxis. Six recent studies have examined the efficacy and safety of prolonged prophylaxis in this setting. Five of these studies have demonstrated that prolonged LMWH prophylaxis (either enoxaparin or dalteparin) for 4--5 weeks is beneficial and significantly superior to conventional prophylaxis for 7--15 days. The other study, using ardeparin, examined clinical endpoints and showed a minor trend but no significant reduction in these events. Furthermore, two of the studies -- one with enoxaparin and one with dalteparin -- also demonstrated a significant reduction in the incidence of proximal deep vein thrombosis. Analysis of all clinical events from the five studies that have published that information shows a halving or 51% reduction in favour of prolonged prophylaxis. On the basis of current evidence, prolonged thromboprophylaxis with LMWH for up to 35 days after major orthopaedic surgery is recommended.

Complications in breast augmentation: prevention and correction

The decision-making process for breast augmentation begins at the initial consultation. Most complications can be avoided with careful planning and decision making. Primary augmentation demands a careful evaluation of the breast morphology and chest wall anatomy. Perioperative techniques such as precise dissection of the pectoralis muscle under direct vision can ensure an adequate pocket, which minimizes the risk for capsular contracture and implant malposition. Secondary breast augmentation for problems such as thinning of the breast skin envelope, long-term pressure atrophy of existing parenchyma, and visibility of the implant can be minimized with appropriate selection of implant type, size, and placement. Patients should understand clearly the immediate and long-term risks associated with breast augmentation and the requirement for future reoperation.