INCIDENTAL VENOUS THROMBOEMBOLISM

In this review we summarized the available evidence on incidental venous thromboembolism (VTE) in order to improve the understanding of its frequency and clinical significance and to provide the adequate therapeutic approach to patients with this disease. In a large systematic review of the literature the weighted prevalence of incidental PE appeared not negligible (2.6%, 95% CI 1.9, 3.4), with high risk in inpatients and in cancer patients. Incidental VTE appeared to be less frequent when we consider other districts than lungs having a prevalence of about 1.7% (95% CI 1.29, 2.34) in abdominal districts with a higher prevalence in patients with cancer and liver cirrhosis. In clinical practice the terms "asymptomatic" or "unuspected" are interchangeably used to describe these events, but this is not totally correct, especially in cancer patients since at least patients with PE may present with nonspecific symptoms such as fatigue, dyspnea, and cough. In cancer patients these symptoms are often attributed to underlying malignancy or side effects of treatment. Interestingly the embolic burden of these patients is not dramatically different form patients presenting with symptomatic PE. Indeed although the embolus load of patients with incidental PE is in general significantly lower than that of those with symptomatic PE, the majority of asymptomatic PE had a proximal localization on lobar or segmental pulmonary arteries. In absence of cancer, in patients with unsuspected VTE, the prognosis of patients who are left untreated seemed to be better than in symptomatic patients. Conversely, in cancer patients the diagnosis of incidental VTE seems to be a negative prognostic factor, with a high mortality rate. Unfortunately, the optimal management of incidental VTE is still a challenging clinical problem, and the current indications suggested by international guidelines are, in general, the same for symptomatic VTE. However, due to the low level of available evidence, other high quality studies are warranted to assess the real effectiveness and safety of anticoagulant therapy in this setting and clarify the correct therapeutic strategy.