Venous Thromboembolism

VTE is a

major cardiovascular disease

that affects persons of all ages and ethnicities

VTE is the

2nd most common cardiovascular disorder

after acute coronary syndrome

PE is the 

3rd leading cause

of cardiovascular death overall and sudden death in hospitalized patients

The estimated total cost of VTE and its complications in Canada is at least

$600 million

per year

50%

of symptomatic VTE are NOT caused by any known risk factors

The main treatment of VTE is blood thinning medication, which is the leading drug class linked to related adverse events

Venous thromboembolism (VTE) includes two conditions: deep vein thrombosis (DVT) and pulmonary embolism (PE).  A DVT is a blood clot in the leg veins, and a PE is a blood clot that travels to the heart and lung circulation. VTE is a major cardiovascular disease that affects adults of all ages and ethnicities, yet has received far less attention than heart attack and stroke. Diagnosed in 1-2 per 1000 persons per year1,2, VTE is the 2nd most common cardiovascular disorder after acute coronary syndrome3.  PE, the most serious form of VTE, is the 3rd leading cause of cardiovascular death overall and sudden death in hospitalized patients4. Acutely, 10% of patients with PE die rapidly prior to diagnosis5, emphasizing the importance of preventing VTE. VTE imposes life-long burden to many patients because of its frequent chronic residual consequences, including repeated episodes of VTE (average recurrence rate off anticoagulants is 5-10% per year)6, the post-thrombotic syndrome (PTS) (occurs in 20-40% of DVT patients) and chronic thromboembolic pulmonary hypertension (occurs in 3-4% of PE patients)7

As the risk of VTE increases steeply with age, our population’s aging demographic portends a rising incidence of VTE. The health care burden of VTE is already quite substantial: the cost to treat an individual case of acute VTE is more than $10,000, and the estimated total cost of VTE and its complications in Canada is at least $600 million per year8,9. Important indirect costs such as loss of productivity that affects patients, families, and society at large are also considerable10,11.

Twenty percent of symptomatic VTE is “provoked”, which means its cause can be linked to a known risk factor such as limb fracture or plaster cast, hospitalization with confinement to bed for 3 days, or use of general anesthesia, each within the previous 3 months.  Thirty percent of symptomatic VTE is associated with cancer12, emphasizing the importance of efforts to prevent VTE in high-risk settings and patient education to ensure early diagnosis. The remaining 50% of patients have “unprovoked” VTE, which means its cause is not linked to a known risk factor.  Patients with suspected VTE present in a wide variety of settings including primary care offices, emergency rooms, inpatient medical and surgical wards and intensive care units. While awaiting diagnostic imaging to confirm VTE, guidelines strongly recommend that patients with suspected VTE should be started on anticoagulant therapy (blood thinners) as the mortality of untreated PE is as high as 1% within 24 hours13. Hence, all health care providers require basic knowledge of VTE prevention, VTE diagnosis and principles of VTE treatment.

Anticoagulants are the mainstay of VTE treatment; they are very effective at preventing VTE extension and VTE recurrence, with relative risk reductions greater than 80%. Anticoagulants are also the leading drug class linked to drug-related adverse events (e.g. life-threatening bleeding)14 and impose patient burden from the need for injections, frequent laboratory monitoring, and lifestyle or dietary modifications. VTE treatment needs to be individualised to optimally balance efficacy and safety. Individualisation increases treatment complexity, which poses knowledge translation (KT) challenges that can be met by developing and validating clinical decision rules to guide clinicians and patients. A number of new oral anticoagulants to prevent and treat VTE have been approved in the last few years, and others are in the development or testing phases15.  The long term efficacy, safety, cost-effectiveness, and comparative effectiveness of these drugs are unknown, and many hospital and community physicians have limited experience with their use. Also, only selected patients were included in the trials that led to regulatory approval of these drugs, leaving key knowledge gaps about the role of new therapies in many important subgroups (obese patients, those with renal dysfunction, pregnant or lactating women, and cancer patients) for the research community to address.

Other important knowledge gaps include inadequately understood causal factors for first and recurrent VTE, inconsistent use of proven measures to prevent VTE, limited community expertise in diagnosing and managing VTE and its complications, and limited knowledge of VTE among the general public.

Taken together, it is evident that VTE is a significant cause of death, short-term sickness, long-term disability and economic burden to the Canadian population, and that further clinical research, from early phase studies to KT, is needed to address important knowledge gaps and improve patient outcomes. With the rising incidence of VTE and, for the first time in 60 years, the availability of numerous new oral drug options besides warfarin to treat VTE, it is an opportune time to take action to address this important public health issue in a focused, highly organized and patient-centred manner. For this reason, we have created the Canadian Venous Thromboembolism Clinical Trials and Outcomes Research (CanVECTOR) Network.

  1. Tagalakis V, Patenaude V, Kahn SR, Suissa S. Incidence of and Mortality from Venous Thromboembolism in a Real-World Population: The Q-VTE Study Cohort. The American Journal of Medicine 2013;126:832.e13-21.

  2. Anderson FA, Wheeler B, Goldberg RJ, et al. A population-based perspective of the hospital incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism. Annals of Internal Medicine 1991;151:933-8.

  3. http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3483991/k.34A8/Statistics.htm#stroke. (Accessed at http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3483991/k.34A8/Statistics.htm#stroke.)

  4. Venous thromboembolism in adult hospitalizations - United States, 2007-2009. MMWR Morb Mortal Wkly Rep 2012;61:401-4.

  5. Stein PD, Beemath A, Olson RE. Trends in the incidence of pulmonary embolism and deep venous thrombosis in hospitalized patients. Am J Cardiol 2005;95:1525-6.

  6. Baglin T, Luddington R, Brown K, Baglin C. Incidence of recurrent venous thromboembolism in relation to clinical and thrombophilic risk factors: prospective cohort study. Lancet 2003;362:523-6.

  7. Pengo V, Kahn S. Chapter 85.  Sequelae of venous thromboembolic disease: Postthrombotic syndrome and chronic thromboembolic pulmonary hypertension. In: Hemostasis and Thrombosis: Basic Principles and Clinical Practice, 6th edition, pgs 1009-1018 Lippincott Williams & Wilkins, November 26, 2012.

  8. Lefebvre P, Laliberté F, Nutescu EA, et al. All-cause and disease-related health care costs associated with recurrent venous thromboembolism. Thrombosis and Haemostasis 2013;110:1288–97.

  9. Ruppert A, Steinle T, Lees M. Economic burden of venous thromboembolism: a systematic review. J Med Econ 2011;14:65-74.

  10. Guanella R, Ducruet T, Johri M, et al. Economic burden and cost determinants of deep vein thrombosis during 2 years following diagnosis: a prospective evaluation. J Thromb Haemost 2011;9:2397-405.

  11. Spyropoulos A. Direct medical costs of venous thromboembolism and subsequent hospital readmission rates: an administrative claims analysis from 30 managed care organizations. J ManagCare Pharm 2007;13:475-86.

  12. White RH. The epidemiology of venous thromboembolism. Circulation 2003;107:I4-I8.

  13. Barritt DW, Jordan SC. Anticoagulant drugs in the treatment of pulmonary embolism. A controlled trial. Lancet 1960;1:1309-12.

  14. Kongkaew C, Hann M, Mandal J, et al. Risk factors for hospital admissions associated with adverse drug events. Pharmacotherapy 2013;33:827-37.

  15. Garcia D, Libby E, Crowther MA. The new oral anticoagulants. Blood 2010;115:15-20.