Venous thromboembolism associated with central venous catheters in patients with cancer: From pathophysiology to thromboprophylaxis, areas for future studies.

Symptomatic catheter related thrombosis (CRT) occurs in 4%-8% of cancer patients. The mean incidence of CRT, detected either by echography or Doppler ranges between 12 and 14% with a high negative predictive value of about 95%, allowing the subsequent occurrence of CRT (symptomatic and asymptomatic) to be safely excluded. Despite its frequency and its medico-economic consequences, no thromboprophylaxis has been validated to date. In most patients, CRT occurs immediately after catheter insertion, most often within the first week and almost all within the first month after insertion. Meta analyses show a reduction of asymptomatic and symptomatic CRT incidence by about 55%-60% using either vitamin K antagonists or low molecular weight heparins without an increased risk of major bleeding. This pharmacological prophylaxis is only effective when started before the central venous catheter insertion at prophylactic doses and thereafter continued at subtherapeutic doses. Since no population at high risk of CRT has been identified, this review focuses on pathophysiology, epidemiology and clinical supportive data that could lead to a new CRT prophylaxis strategy.