Elsevier

Thrombosis Research

Volume 142, June 2016, Pages 11-16
Thrombosis Research

Full Length Article
Retrospective review on isolated distal deep vein thrombosis (IDDVT) — A benign entity or not?

https://doi.org/10.1016/j.thromres.2016.04.003Get rights and content

Highlights

  • IDDVT patients in this review had a non-inferior rate of thrombosis recurrence compared to major VTE.

  • IDDVT patients had a non-inferior rate of prospective malignancy detection compared to major VTE.

  • Similar rates of long-term complications show that the IDDVT significance should not be understated.

Abstract

Introduction

Isolated distal deep venous thrombosis (IDDVT) is traditionally associated with less severe clinical sequelae, with ongoing debate on multiple aspects of its management. Despite numerous studies evaluating its acute management, there remains a paucity of data evaluating long-term complications such as recurrence and subsequent malignancy. We aim to evaluate the characteristics of IDDVT in institutions that routinely perform whole leg ultrasonography, and the risks of recurrence and complications in comparison to major venous thromboembolism (major VTE; defined as above-knee or proximal DVT and pulmonary embolism (PE)).

Methods

Retrospective evaluation of consecutive IDDVT and major VTE from July 2011 to December 2012 in a hospital network in Melbourne, Australia. Patients were followed up for a minimum of 24 months. Patients with active malignancy were excluded.

Results

Of 1024 VTE cases, there were 164 non-cancer patients (92 males, 72 females, median age of 61 years) with IDDVT. Compared to major VTE, IDDVT was more likely to be provoked (73% vs 59%, p < 0.01), has shorter duration of anticoagulation (median 3.5 months vs 6.0 months, p < 0.01) and less clinically significant bleeding (2.4% vs 6.7%, p = 0.05), independent of duration of therapy. Recurrence was non-inferior compared to major VTE (10% vs 7%, p = 0.36) and 60% recurred with major VTE. Three (1.8%) were subsequently diagnosed with cancer (vs 1.9% in major VTE, p = 0.97).

Conclusions

IDDVT has non-inferior rates of recurrence and subsequent cancer detection compared to major VTE and hence, its clinical significance should not differ from major VTE. Further studies are required to determine the adequate length of anticoagulation.

Introduction

Isolated distal deep vein thrombosis (IDDVT) is a common variant of venous thromboembolism (VTE) which accounts for approximately 23%–59% of all deep vein thrombosis (DVT) [1]. The risk of pulmonary embolism (PE), a major comorbidity of VTE, was observed to be low in untreated patients with IDDVT with the CALTHRO study reporting a 1.6% incidence during a 3-month follow-up period [2]. Most studies, although not all [3], also reported lower VTE recurrence risk [4], [5], [6]. Hence, when occurring in isolation, IDDVT is generally considered to be more “benign” compared to proximal DVT and/or pulmonary embolism (PE).

Despite their frequent occurrence, the investigation and management of IDDVT are heterogeneous and there remains no standard of care [7], [8]. In fact, in some institutions, compression ultrasonography is limited to the proximal veins without extension to the distal veins, thus possibly leading to the under-diagnosis of distal vein thrombosis [9]. In addition, serial proximal ultrasound is not infrequently only reserved for high-risk patients [8]. The lack of standardised care is due to inconsistent findings in many aspects of IDDVT including immediate thrombotic complications such as proximal DVT extension and PE, and also late VTE recurrence. This is reflected by conflicting recommendations provided by different guidelines, with some recommending observation with serial ultrasonography in low to medium risk patients [10], while others recommending 3 months of upfront treatment [11].

Many ongoing studies, such as CACTUS [9] and TWISTER (NVT01252420), are focusing on the duration of anticoagulation after an acute event. However, there remains a paucity of studies evaluating long-term complications such as thrombosis recurrence and subsequent malignancy. Knowledge of these complications may assist in clarifying both the optimal treatment duration, and also the adequate clinical assessment required for the individual with an IDDVT.

We aim to review the real-life IDDVT management strategies in the warfarin era at two major tertiary hospitals in Northeast Melbourne, where whole leg ultrasound is routinely performed, as well as evaluate epidemiological risk factors and recurrence rates. This is a subset of a larger audit, which evaluated all types of VTE.

Section snippets

Methods

A retrospective analysis was conducted of consecutive patients presenting with VTE during an 18-month period, between July 2011 and December 2012, at two major tertiary teaching hospitals in Melbourne, Australia (Austin Health and Northern Health). Both the tertiary institutions are the only tertiary hospitals serving Northeast Melbourne with an estimated combined population of more than 1.5 million, and constitute the main referral centres for these areas. VTE-related presentations were

Results

A total of 1024 VTE events were identified during the 18-month study recruitment period, involving 1002 patients with 22 recurrent presentations within the period. Excluding patients with known active malignancy, superficial VTE, dural sinus thrombosis and portal vein thrombosis, 578 patients had major VTE (total of 586 events) while 164 patients (total of 166 events) had IDDVT, approximating 22% of all non-cancer VTE patients (Fig. 1). Seventy-seven and eighty-seven patients were affected in

Discussion

This retrospective population-based study reaffirms that IDDVT is relatively common (22% of all non-cancer related VTE), albeit less common than proximal VTE, which is similar to previous studies [1], [3]. The higher incidence compared to the Worcester study [3] is likely due to the routine use of whole-leg ultrasound study in Australia, which leads to increased IDDVT diagnosis.

Despite IDDVT being common, the management strategies remained diverse. Most patients (88%), however, did received

Conclusion

IDDVT patients in this retrospective observational cohort had a non-inferior rate of thrombosis recurrence and prospective malignancy detection, compared to major VTE, despite the lower overall thrombosis burden. This suggests that while the medical community generally considers IDDVT as a benign entity, the incidence of late complications such as recurrence and subsequent malignancies should not be neglected. Appropriate surveillance for these complications remains important in this population

Conflicts of interest

None to declare.

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