Assessing Recurrence Risk Following Acute Venous Thromboembolism

Use of Algorithms

Daniela Poli; Gualtiero Palareti


Curr Opin Pulm Med. 2013;19(5):407-412. 

In This Article

Abstract and Introduction


Purpose of review: Venous thromboembolism (VTE) is a chronic disease, associated with a significant rate of recurrence, lower in patients with events provoked by transient risk factors and higher in unprovoked cases. Short-term treatment is indicated for provoked VTE, long-term treatment should be considered for unprovoked. The aim of this review is to evaluate the risk factors for recurrence and the decisional algorithms available to guide patients' management.

Recent findings: To identify patients who carry a high recurrent risk and require long-term treatment, three algorithms have been proposed: the HERDOO2, the Vienna prediction model, and the DASH score. All identify male sex and elevated D-dimer levels as important risk factors for recurrence. However, important differences among the models should be outlined: in the HERDOO2 model, D-dimer levels are measured during anticoagulation and not after its withdrawal; furthermore, it indicates age greater than 65 as a risk factor for recurrence, whereas the DASH score attributes a higher risk to age less than 50. The Vienna model is complex for routine use.

Summary: Further studies are needed to clarify these discrepancies. A management study based on D-dimer levels after anticoagulation withdrawal is ongoing and could indicate a simple way to safely manage these patients.


Venous thromboembolism (VTE) is a chronic disease, associated with a significant rate of recurrence, that varies in relation to the type of the first event and the associated risk factors. Predicting the likelihood of recurrence is important to identify patients who need long-term anticoagulation. The expected recurrence rate is lower in patients with VTE provoked by transient trigger factors, such as surgery, trauma, immobilization, pregnancy, or puerperium. A recent systematic review[1] has shown, however, that the risk of recurrence is not the same with all trigger factors; the rate of recurrence was, in fact, 0.7 and 4.2% after a surgical or nonsurgical factor, respectively. Other conditions, such as the use of oral contraceptives, have been evaluated as minor risk factors by some authors[2] and not by others.[3,4] The rate of recurrence is for sure higher among those patients with unprovoked events, reaching 10% after 1 year and 30% after 5 year.[5] On the basis of the characteristics of VTE presentation, provoked or unprovoked, available guidelines[5,6] are in agreement in recommending a short period of treatment (3 months) for patients with provoked VTE and suggesting a longer period of anticoagulation in those with unprovoked VTE. It is recommended that all these patients undergo evaluation of the risk-to-benefit ratio of long-term anticoagulation by estimating the individual bleeding risk and suggesting stopping therapy after 3 months in patients at high bleeding risk and to continue therapy in those at moderate-to-low bleeding risk.[5,6] Unfortunately, no adequate models to evaluate bleeding risk in VTE patients are availabl.[7,8] The score proposed by the panel of authors of the recent American College of Chest Physicians (ACCP) guidelines[5] is based only on a consensus of experts and still requires an adequate validation before extensive use.

With different approaches, several authors addressed the problem of the stratification of patients with unprovoked VTE on the basis of clinical risk factors, including patient's sex, comorbidities, or by measuring the laboratory markers, with the aim of estimating the recurrence risk. Three algorithms[9,10,11] have been proposed for this purpose. None of them take into account the bleeding risk.