Should we be looking for and treating isolated calf vein thrombosis?

Characteristics and Treatment Strategy of Isolated Calf Deep Venous Thrombosis after Fractures: A Review of Recent Literature

Isolated calf deep venous thrombosis (ICDVT) includes thrombosis located at the far end of the popliteal vein, such as the anterior tibial vein, posterior tibial vein, fibular vein, and intramuscular vein of the soleus and gastrocnemius. This type of thrombosis has the highest incidence, accounting for approximately half of all deep vein thrombosis (DVT) cases; however, there is no consistent recommendation for ICDVT treatment across countries, and there is also no optimal management strategy. In recent years, increasing evidence has shown that ICDVT can develop into proximal DVT, even causing pulmonary embolism (PE). Therefore, some experts suggest anticoagulant therapy for this type of DVT, while others hold an opposing attitude. Therefore, the treatment strategy for this type of DVT has become a hot and difficult research topic. The purpose of this review is to summarize the characteristics of ICDVT and the effects of different treatment strategies by analyzing recent and important classical works in the literature in an attempt to provide recommendations for the treatment of this most common type of DVT in orthopaedic clinics.

Incidence and risk factors of preoperative isolated calf deep venous thrombosis following hip fractures

There is still a lack of data on isolated calf deep vein thrombosis (ICDVT) following hip fractures surgery. The study aimed to determine the incidence of preoperative ICDVT and the associated risk factors in patients with hip fractures requiring surgery.The 289 patients who required hip surgery were included, duplex ultrasonography was routinely used to make a definite diagnosis of preoperative ICDVT located in unilateral or bilateral calf. Data on demographics and laboratory-associated blood biomarkers results were included. Univariate analyses were used to analyse the data of demographics, comorbidities, personal history operation related indexes and laboratory biomarkers, then the multivariate logistic regression analysis was employed to identify the independent risk factors associated with ICDVT.Sixty-eight (23.5%) patients were diagnosed with preoperative ICDVTs. The univariate analyses showed significant differences regarding ICDVT were age, current smoking, alcohol consumption, time from injury to operation, albumin, white blood cells, lymphocyte, red blood cells, hemoglobin, hematocrit, and activated partial thromboplastin time level among the 44 factors. The multivariable model confirmed 3 risk factors were significantly independent in association with preoperative ICDVTs, including current smoking, time delay from injury to operation and activated partial thromboplastin time ( < 28seconds).The incidence of preoperative ICDVT in hip fracture was 23.5%, and patients with associated risk factors are prone to form ICDVTs, identification of these factors may help to reduce the incidence of ICDVT with hip fractures by taking early prevention measures.

Calf deep vein thrombosis – clinical relevance, diagnostic approaches and therapeutic options

Summary. Isolated distal deep vein thromboses (IDDVT) represent up to 50 % of legs deep vein thromboses (DVT). However, since their natural history is to date unknown, the need to diagnose and treat them is a matter of debate. The diagnostic strategy based on the assessment of pre-test probability and D-dimer demonstrated a scarse efficiency for IDDVT. The choice between a proximal and a complete ultrasonographic approach should be guided by the clinical context, the local expertise and the patient characteristics. Randomized and observational studies have analyzed the need of therapy and compared different regimens of anticoagulation, with conflicting results. Systematic reviews and meta-analyses tend to support the usefulness of an anticoagulant treatment, even if the optimal dose and duration are not still defined. A careful stratification of the patient’s profile, taking into account risk factors for proximal extension, recurrence and bleeding should address the therapeutic approach, which must always be discussed with an adequately informed patient. Further studies aimed to clarify the natural history of IDDVT, and to assess safety and efficacy of lower intensity and shorter duration protocols are urgently needed.

Deep Venous Thrombosis in a Patient with a Moderate Pretest Probability and a Negative D-Dimer Test: A Review of the Diagnostic Algorithms

Modern diagnostic strategies of venous thromboembolism (VTE) have been developed. In this review, the diagnostic algorithms for deep-vein thrombosis (DVT) and their parameters are discussed individually in the context of reporting a case of DVT in a 43-year-old Caucasian female with a moderate pretest probability stratified by Wells’ score and a negative high quality D-dimer test. The patient was on treatment with Xarelto (rivaroxaban), 20 mg PO daily at the time of presentation. The diagnosis was verified through a complete lower limb ultrasound (US). This case highlights the diagnostic challenges and pitfalls of the current algorithms, especially those seen in a subgroup of patients such as patients with cancer, pregnancy, recurrent VTE or are on anticoagulation therapy at the time of presentation. The diagnosis of DVT is less plausible in a patient who is on anticoagulation therapy, but physicians should be aware of such a possibility. Physicians should also know in advance the numerous clinically relevant limitations of D-dimer testing before interpreting the results. Unifying the current diagnostic strategies, modifying the current Wells’ score and using the protocol of a whole-leg compression US instead of the limited US protocol are among the several cautious suggestions that have been proposed based on this review to possibly decrease the incidence of missed DVT.

Pharmacological thromboprophylaxis to prevent venous thromboembolism in patients with temporary lower limb immobilization after injury: systematic review and network meta-analysis

BACKGROUND

Thromboprophylaxis has the potential to reduce venous thromboembolism (VTE) following lower limb immobilization resulting from injury.

OBJECTIVES

We aimed to estimate the effectiveness of thromboprophylaxis, compare different agents, and identify any factors associated with effectiveness.

METHODS

We undertook a systematic review and network meta-analysis (NMA) of randomized trials reporting VTE or bleeding outcomes that compared thromboprophylactic agents with each other or to no pharmacological prophylaxis, for this indication. An NMA was undertaken for each outcome or agent used, and a series of study-level network meta-regressions examined whether population characteristics, type of injury, treatment of injury, or duration of thromboprophylaxis were associated with treatment effect.

RESULTS

Data from 6857 participants across 13 randomized trials showed that, compared with no treatment, low molecular weight heparin (LMWH) reduced the risk of any VTE (odds ratio [OR]: 0.52; 95% credible interval [CrI]: 0.37-0.71), clinically detected deep vein thrombosis (DVT) (OR: 0.39; 95% CrI: 0.12-0.94) and pulmonary embolism (PE) (OR: 0.16; 95% CrI: 0.01-0.74), whereas fondaparinux reduced the risk of any VTE (OR: 0.13; 95% CrI: 0.05-0.30) and clinically detected DVT (OR: 0.10; 95% CrI: 0.01-0.86), with inconclusive results for PE (OR: 0.40; 95% CrI: 0.01-7.53).

CONCLUSIONS

Thromboprophylaxis with either fondaparinux or LMWH appears to reduce the odds of both asymptomatic and clinically detected VTE in people with temporary lower limb immobilization following an injury. Treatment effects vary by outcome and are not always conclusive. We were unable to identify any treatment effect modifiers other than thromboprophylactic agent used.

Thromboprophylaxis in lower limb immobilisation after injury (TiLLI)

Venous thromboembolic disease is a major global cause of morbidity and mortality. An estimated 10 million episodes are diagnosed yearly; over half of these episodes are provoked by hospital admission/procedures and result in significant loss of disability adjusted life years. Temporary lower limb immobilisation after injury is a significant contributor to the overall burden of venous thromboembolism (VTE). Existing evidence suggests that pharmacological prophylaxis could reduce overall VTE event rates in these patients, but the proportional reduction of symptomatic events remains unclear. Recent studies have used different pharmacological agents, dosing regimens and outcome measures. Consequently, there is wide variation in thromboprophylaxis strategies, and international guidelines continue to offer conflicting advice for clinicians. In this review, we provide a summary of recent evidence assessing both the clinical and cost effectiveness of thromboprophylaxis in patients with temporary immobilisation after injury. We also examine the evidence supporting stratified thromboprophylaxis and the validity of widely used risk assessment methods.

BET 2: Striking the right balance: anticoagulation and isolated distal deep vein thrombosis

A short-cut review was carried out to establish whether treatment of isolated distal deep vein thrombosis with therapeutic anticoagulation can reduce adverse clinical outcomes. A meta-analysis from 2011 and 11 subsequent directly relevant papers were found using the reported search strategy. Of these, 7 in total presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated. It is concluded that patients diagnosed with isolated distal deep vein thrombosis should be individually risk assessed and treated according to their risk of thrombotic complication, bleeding with anticoagulation and personal preference.

Emergency Department Management of Suspected Calf-Vein Deep Venous Thrombosis: A Diagnostic Algorithm

Introduction

Unilateral leg swelling with suspicion of deep venous thrombosis (DVT) is a common emergency department (ED) presentation. Proximal DVT (thrombus in the popliteal or femoral veins) can usually be diagnosed and treated at the initial ED encounter. When proximal DVT has been ruled out, isolated calf-vein deep venous thrombosis (IC-DVT) often remains a consideration. The current standard for the diagnosis of IC-DVT is whole-leg vascular duplex ultrasonography (WLUS), a test that is unavailable in many hospitals outside normal business hours. When WLUS is not available from the ED, recommendations for managing suspected IC-DVT vary. The objectives of the study is to use current evidence and recommendations to (1) propose a diagnostic algorithm for IC-DVT when definitive testing (WLUS) is unavailable; and (2) summarize the controversy surrounding IC-DVT treatment.

Discussion

The Figure combines D-dimer testing with serial CUS or a single deferred FLUS for the diagnosis of IC-DVT. Such an algorithm has the potential to safely direct the management of suspected IC-DVT when definitive testing is unavailable. Whether or not to treat diagnosed IC-DVT remains widely debated and awaiting further evidence.

Conclusion

When IC-DVT is not ruled out in the ED, the suggested algorithm, although not prospectively validated by a controlled study, offers an approach to diagnosis that is consistent with current data and recommendations. When IC-DVT is diagnosed, current references suggest that a decision between anticoagulation and continued follow-up outpatient testing can be based on shared decision-making. The risks of proximal progression and life-threatening embolization should be balanced against the generally more benign natural history of such thrombi, and an individual patient’s risk factors for both thrombus propagation and complications of anticoagulation.

Drug Treatment of Venous Thromboembolism in the Elderly

Half of all patients with acute venous thromboembolism are aged over 70 years; they then face the added hazard of an age-related increase in the incidence of major bleeding. This makes it even more important to weigh the balance of benefit and risk when considering anticoagulant treatment and treatment duration. Traditional treatment with a heparin (usually low molecular weight) followed by a vitamin K antagonist such as warfarin is effective but is often complicated, especially in the elderly. The direct-acting oral anticoagulants (DOACs), i.e. the thrombin inhibitor dabigatran and the factor Xa inhibitors rivaroxaban, apixaban and edoxaban, are given in fixed doses, do not need laboratory monitoring, have fewer drug-drug interactions and are therefore much easier to take. Randomised trials, their meta-analyses and 'real-world' data indicate the DOACs are no less effective than warfarin (are non-inferior) and probably cause less major bleeding (especially intracranial). It seems the relative safety of DOACs extends to age above 65 or 70 years, although bleeding becomes more likely regardless of the chosen anticoagulant. Renal impairment, comorbidities (especially cancer) and interventions are special hazards. Ways to minimise bleeding include patient selection and follow-up, education about venous thromboembolism, anticoagulants, drug interactions, regular checks on adherence and avoiding needlessly prolonged treatment. The relatively short circulating half-lives of DOACs mean that time, local measures and supportive care are the main response to major bleeding. They also simplify the management of invasive interventions. An antidote for dabigatran, idarucizumab, was recently approved by regulators, and a general antidote for factor Xa inhibitors is in advanced development.