Proactive Thrombosis Prevention 2008

To help kick off DVT Awareness Month 2008, we held our third annual "Proactive Thrombosis Prevention" Harvard Medical School CME accredited community event at Brigham and Women’s Hospital on Saturday, March 1, 2008. This event, sponsored by the North American Thrombosis Forum (NATF), is a comprehensive multidisciplinary overview of current thrombosis prevention methods geared to physicians, nurses, physician assistants, pharmacists, hospitalists, and hospital administrators. In addition to health care professionals, patients and caregivers were encouraged to attend.

Overview of Venous Thromboembolism Epidemiology–Samuel Z. Goldhaber, MD

Pulmonary embolism (PE) and deep venous thrombosis (DVT) afflict millions of individuals worldwide and account for several hundred thousand deaths annually in the United States. Few health care providers realize that the case fatality rate for PE, approximately 15 percent, exceeds the mortality rate for acute myocardial infarction. During the past 5 years, a remarkable transition started in North America. The lay public began to become aware of the magnitude of disability from venous thromboembolism (VTE), which encompasses PE and DVT.

The same features of VTE that fascinate the public have kept clinical scientists spellbound by this illness. VTE is a common problem, yet often difficult to diagnose. It strikes a wide range of individuals, from teenagers to nonagenarians. Its onset is usually unpredictable, and the likelihood of recurrence after completing a time-limited course of anticoagulation remains uncertain. Though most individuals survive, VTE impairs quality of life by increasing susceptibility to chronic thromboembolic pulmonary hypertension and chronic venous insufficiency. It also exerts a psychological toll on patients who wonder whether they will suffer a recurrent event, whether it will affect their family members, and whether it will lower their quality of life as well as shorten their lifespan.

The incidence of VTE has also risen, primarily because of an increase in the diagnosis of DVT. The incidence is similar among men and women. VTE strikes immobilized hospitalized patients with comorbid disease. Less well appreciated are risk factors out-of-hospital: 1) obesity, 2) cigarette smoking, 3) age, 4) cancer (including liquid tumors), 5) long-haul air travel, and 6) “asymptomatic” DVT.

The previous uncertainty about the clinical relevance of asymptomatic proximal DVT no longer exists. Asymptomatic proximal leg DVT has a high associated mortality rate among patients hospitalized with medical illnesses. The 90-day mortality rate in hospitalized medical patients was 14% for those with asymptomatic proximal leg DVT at Day 21, compared with a 1.9% 90-day mortality rate for those with no DVT at Day 21. This finding underscores the appropriateness of targeting asymptomatic proximal leg DVT as an endpoint in clinical trials of thromboprophylaxis.

An especially problematic risk factor is obesity, which has become pandemic in the United States. Obesity doubles or triples the likelihood of VTE. As patients survive longer with cancer, the frequency of VTE is increasing, because cancer patients have twice the incidence of VTE as noncancer patients. This increased risk of VTE is present not only in adenocarcinomas of the pancreas, stomach, lung, esophagus, prostate, and colon, but also threatens patients with “liquid tumors” such as myeloproliferative disease, lymphoma, and leukemia. The VTE incidence is highest among patients initially diagnosed with metastatic disease. Less well known acquired risk factors include acute infection and chronic obstructive pulmonary disease.

The epidemiology of PE is also a women’s health issue. Pregnancy, hormonal contraception, and postmenopausal hormonal therapy each contribute to increased risk.

Perhaps the most frequently discussed acquired risk factor is longhaul air travel. The risk of fatal PE in this setting is less than 1 in 1,000,000. However, when death occurs, it is dramatic and especially tragic because the victim is often an otherwise healthy young person. It appears that among some individuals, there is activation of the coagulation system during air travel. The reason for hypercoagulability remains uncertain. However, the mechanism does not appear to be due to hypobaric hypoxia.

Hospitalized patients with medical illnesses such as pneumonia or congestive heart failure are at high risk of developing VTE. The stasis and immobilization associated with postoperative venous thrombosis may paradoxically increase after hospital discharge, because with short hospital lengths of stay, patients may be too weak and debilitated at home to ambulate after surgery. Vigilance is required to ensure that appropriate patients receive extended VTE prophylaxis at the time of hospital discharge.

The VTE cost burden is high. VTE is often a chronic illness, with a high recurrence rate. DVT and PE impair the quality of life. The DVT FREE Registry is improving our understanding of VTE epidemiology.

REFERENCES

1. Goldhaber SZ, Tapson VF: A prospective registry of 5,451 patients with ultrasound-confirmed deep vein thrombosis. Am J Cardiol 93:259-262, 2004.
2. Stein PD, Kayali F, Olson RE: Estimated case fatality rate of pulmonary embolism, 1979 to 1998. Am J Cardiol 93:1197-1199, 2004.
3. Stein PD, Beemath A, Olson RE: Trends in the incidence of pulmonary embolism and deep vein thrombosis in hospitalized patients. Am J Cardiol 95:1525-1526, 2005.
4. Cushman M, Tsai AW, White RH, et al: Deep vein thrombosis and pulmonary embolism in two cohorts: the longitudinal investigation of thromboembolism etiology. Am J Med 117:19-25, 2004.
5. Bova C, Marchiori A, Noto A, et al: Incidence of arterial cardiovascular events in patients with idiopathic venous thromboembolism: A retrospective cohort study. Thromb Haemost 96:132-136, 2006.
6. Vaitkus PT, Leizorovicz A, Cohen AT, et al: Mortality rates and risk factors for asymptomatic deep vein thrombosis in medical patients. Thromb Haemost 93:76-79, 2005.
7. Stein PD, Beemath A, Olson RE: Obesity as a risk factor in venous thromboembolism. Am J Med 118:978-980, 2005.
8. Stein PD, Beemath A, Meyers FA, et al: Incidence of venous thromboembolism in patients hospitalized with cancer. Am J Med 119:60- 68, 2006.
9. Chew HK, Wun T, Harvey D, et al: Incidence of venous thromboembolism and its effect on survival among patients with common cancers. Arch Intern Med 166:458-464, 2006.
10. Smeeth L, Cook C, Thomas S, et al: Risk of deep vein thrombosis and pulmonary embolism after acute infection in a community setting. Lancet 367:1075-1079, 2006.
11. Tillie-Leblond I, Marquette CH, Perez T, et al: Pulmonary embolism in patients with unexplained exacerbation of chronic obstructive pulmonary disease: prevalence and risk factors. Ann Intern Med 144:390-396, 2006.
12. David PS, Boatwright EA, Tozer BS, et al: Hormonal contraception update. Mayo Clin Proc 81:949-954, 2006.
13. Curb JD, Prentice RL, Bray PF, et al: Venous thrombosis and conjugated equine estrogen in women without a uterus. Arch Intern Med 166:772-780, 2006.
14. Parkin L, Bell ML, Herbison GP, et al: Air travel and fatal pulmonary embolism. Thromb Haemost 95:807-814, 2006.
15. Schreijer AJ, Cannegieter SC, Meijers JC, et al: Activation of coagulation system during air travel: a crossover study. Lancet 367:832-838, 2006.
16. Toff WD, Jones CI, Ford I, et al: Effect of hypobaric hypoxia, simulating conditions during long-haul air travel, on coagulation, fibrinolysis, platelet function, and endothelial activation. JAMA 295:2251-2261, 2006.
17. Heit JA: The epidemiology of venous thromboembolism in the community: implications for prevention and management. J Thromb Thrombolysis 21:23-29, 2006.

Program Presentations: Saturday, March 1, 2008

1.	Stroke Update Farzaneh A. Sorond, MD, PhD
2.	Coronary Stent Thrombosis Frederic S. Resnic, MD, MSc
3.	Peripheral Arterial Disease Update Marie Gerhard-Herman, MD
4.	PE Diagnosis Paul D. Stein, MD
5.	Heparin-Induced Thrombocytopenia Education Programs Steven Baroletti, PharmD, MBA
6.	Generic vs. Brand Name Drugs Jawed Fareed, PhD
7.	Electronic Alerts to Prevent DVT Karen Fiumara, PharmD
8.	Novel Anticoagulants John Fanikos, RPh, MBA
9.	Anticoagulation Update Samuel Z. Goldhaber, MD
10.	Patient Education and Patient Compliance Rita M. Morrison, RN, BSN and Ruth B. Morrison, RN, BSN, CVN
11.	Point-of-Care INR Testing Jack E. Ansell, MD
12.	Patient Advocacy Kelly Clark, NATF Patient Advocate

 

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