venous thromboembolism

Last edited 05/2020 and last reviewed 07/2021

Venous thromboembolism (VTE) is when a thrombus (blood clot) forms in a vein which may dislodge from its site of origin to travel in the blood, an occurrence known as embolism (1).

• majority of thrombus formation occurs in the deep veins of the leg, hence the most frequent manifestation of VTE is deep venous thrombosis (DVT)
• almost two thirds of VTE cases are isolated DVTs (2)
• a dislodged thrombus may travel to the lung and cause pulmonary embolism (PE) (1,3).

It is the third most commonest vascular disease after coronary artery disease and stroke (4).
Incidence of VTE increases sharply with age:

• women are more often affected at a younger age while in the elderly, this ratio reverses
• a lower incidence is seen in Asians (2)

VTE is an important cause of death in hospitalised patients (1).

• all patients admitted to the hospital or presenting acutely to hospital should be individually assessed for risk of VTE and bleeding
• this assessment should be repeated regularly and at least every 48 hours (5)

Venous thromboembolism (VTE), clinically presenting as DVT or PE, is globally the third most frequent acute cardiovascular syndrome behind myocardial infarction and stroke (6):

• annual incidence rates for PE range from 39-115 per 100 000 population; for DVT, incidence rates range from 53-162 per 100 000 population
• cross-sectional data show that the incidence of VTE is almost eight times higher in individuals aged >= 80 years than in the fifth decade of life.

Various risk factors for VTE have been categorised (6)

HIV = human immunodeficiency virus; OR = odds ratio

Reference:

• (1) NICE (March 2020). Venous thromboembolic diseases: diagnosis, management and thrombophilia testing.
• (2) Mazzolai L et al. Diagnosis and management of acute deep vein thrombosis: a joint consensus document from the European society of cardiology working groups of aorta and peripheral circulation and pulmonary circulation and right ventricular function. Eur Heart J. 2017 Feb 17.    
• (3) Snow V et al. Management of venous thromboembolism: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med. 2007;146(3):204-10
• (4) Douketis JD. Treatment of deep vein thrombosis: what factors determine appropriate treatment? Can Fam Physician. 2005;51:217-23
• (5) Scottish Intercollegiate Guidelines Network (SIGN) 2010. Prevention and Management of Venous Thromboembolism.
• (6) Konstantinides SV et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS) The Task Force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC). Eur Respir J. 2019 Oct 9;54(3).