Treatment of distal deep vein thrombosis

Treating Deep Venous Thrombosis in a Background of Crohn's Disease: A Clinical Conundrum

Deep venous thrombosis (DVT) commonly affects the lower extremities, often as a result of prolonged immobilization. However, upper limb DVT is an atypical presentation, typically associated with risk factors such as the use of a peripherally inserted central catheter (PICC) line. This case report describes an uncommon case of DVT management in a patient with Crohn's disease, a condition more frequently characterized by painful lower gastrointestinal symptoms and chronic diarrhea. A 22-year-old male with a history of Crohn's disease developed swelling and purplish discoloration at the brachial site of a PICC line site. Laboratory results indicated anemia with a hemoglobin level of 9.9 g/dL and a hematocrit of 31.9%. Doppler ultrasound confirmed the DVT in the left long axillary, left subclavian, and left long basilic veins. Given the patient's concurrent lower gastrointestinal bleeding, a cautious approach was required to balance the risks and benefits of anticoagulation. Upon recommendation by Hematology, a prophylactic dose of enoxaparin was initiated and subsequently escalated to a therapeutic dose as tolerated. The patient's condition was closely monitored, and he successfully reached the full therapeutic regimen without complications. This case underscores the importance of individualized DVT treatment strategies in the context of concurrent Crohn's disease, offering insights into managing anticoagulation in the presence of bleeding risks.

Pathogenesis of Two Faces of DVT: New Identity of Venous Thromboembolism as Combined Micro-Macrothrombosis via Unifying Mechanism Based on "Two-Path Unifying Theory" of Hemostasis and "Two-Activation Theory of the Endothelium"

Venous thrombosis includes deep venous thrombosis (DVT), venous thromboembolism (VTE), venous microthrombosis and others. Still, the pathogenesis of each venous thrombosis is not clearly established. Currently, isolated distal DVT and multiple proximal/central DVT are considered to be the same macrothrombotic disease affecting the venous system but with varying degree of clinical expression related to its localization and severity. The genesis of two phenotypes of DVT differing in clinical features and prognostic outcome can be identified by their unique hemostatic mechanisms. Two recently proposed hemostatic theories in vivo have clearly defined the character between "microthrombi" and "macrothrombus" in the vascular system. Phenotypic expression of thrombosis depends upon two major variables: (1) depth of vascular wall damage and (2) extent of the injury affecting the vascular tree system. Vascular wall injury limited to endothelial cells (ECs) in sepsis produces "disseminated" microthrombi, but intravascular injury due to trauma extending from ECs to subendothelial tissue (SET) produces "local" macrothrombus. Pathogen-induced sepsis activates the complement system leading to generalized endotheliopathy, which releases ultra large von Willebrand factor (ULVWF) multimers from ECs and promotes ULVWF path of hemostasis. In the venous system, the activated ULVWF path initiates microthrombogenesis to form platelet-ULVWF complexes, which become "microthrombi strings" that produce venous endotheliopathy-associated vascular microthrombotic disease (vEA-VMTD) and immune thrombocytopenic purpura (ITP)-like syndrome. In the arterial system, endotheliopathy produces arterial EA-VMTD (aEA-VMTD) with "life-threatening" thrombotic thrombocytopenic purpura (TTP)-like syndrome. Typically, vEA-VMTD is "silent" unless complicated by additional local venous vascular injury. A local venous vessel trauma without sepsis produces localized macrothrombosis due to activated ULVWF and tissue factor (TF) paths from damaged ECs and SET, which causes distal DVT with good prognosis. However, if a septic patient with "silent" vEA-VMTD is complicated by additional vascular injury from in-hospital vascular accesses, "venous combined micro-macrothrombosis" may develop as VTE via the unifying mechanism of the "two-path unifying theory" of hemostasis. This paradigm shifting pathogenetic difference between distal DVT and proximal/central DVT calls for a reassessment of current therapeutic approaches.

Treatment of distal deep vein thrombosis

BACKGROUND

The treatment of distal (below the knee) deep vein thrombosis (DVT) is not clearly established. Distal DVT can either be treated with anticoagulation, or monitored with close follow-up to detect progression to the proximal veins (above the knee), which requires anticoagulation. Proponents of this monitoring strategy base their decision to withhold anticoagulation on the fact that progression is rare and most people can be spared from potential bleeding and other adverse effects of anticoagulation.

OBJECTIVES

To assess the effects of different treatment interventions for people with distal (below the knee) deep vein thrombosis (DVT).

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 12 February 2019. We also undertook reference checking to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) for the treatment of distal DVT.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. We resolved disagreements by discussion. Primary outcomes of interest were recurrence of venous thromboembolism (VTE), DVT and major bleeding and follow up ranged from three months to two years. We performed fixed-effect model meta-analyses with risk ratio (RRs) and 95% confidence intervals (CIs). We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We identified eight RCTs reporting on 1239 participants. Five trials randomised participants to anticoagulation for up to three months versus no anticoagulation. Three trials compared anticoagulation treatment for different time periods. Anticoagulant compared to no intervention or placebo for distal DVT treatment Anticoagulation with a vitamin K antagonist (VKA) reduced the risk of recurrent VTE during follow-up compared with participants receiving no anticoagulation (RR 0.34, 95% CI 0.15 to 0.77; 5 studies, 496 participants; I² = 3%; high-certainty evidence), and reduced the risk of recurrence of DVT (RR 0.25, 95% CI 0.10 to 0.67; 5 studies, 496 participants; I² = 0%; high-certainty evidence). There was no clear effect on risk of pulmonary embolism (PE) (RR 0.81, 95% CI 0.18 to 3.59; 4 studies, 480 participants; I² = 0%; low-certainty evidence). There was little to no difference in major bleeding with anticoagulation compared to placebo (RR 0.76, 95% CI 0.13 to 4.62; 4 studies, 480 participants; I² = 26%; low-certainty evidence). There was an increase in clinically relevant non-major bleeding events in the group treated with anticoagulants (RR 3.34, 95% CI 1.07 to 10.46; 2 studies, 322 participants; I² = 0%; high-certainty evidence). There was one death, not related to PE or major bleeding, in the anticoagulation group. Anticoagulation for three months or more compared to anticoagulation for six weeks for distal DVT treatment Three RCTs of 736 participants compared three or more months of anticoagulation with six weeks of anticoagulation. Anticoagulation with a VKA for three months or more reduced the incidence of recurrent VTE to 5.8% compared with 13.9% in participants treated for six weeks (RR 0.42, 95% CI 0.26 to 0.68; 3 studies, 736 participants; I² = 50%; high-certainty evidence). The risk for recurrence of DVT was also reduced (RR 0.32, 95% CI 0.16 to 0.64; 2 studies, 389 participants; I² = 48%; high-certainty evidence), but there was probably little or no difference in PE (RR 1.05, 95% CI 0.19 to 5.88; 2 studies, 389 participants; I² = 0%; low-certainty evidence). There was no clear difference in major bleeding events (RR 3.42, 95% CI 0.36 to 32.35; 2 studies, 389 participants; I² = 0%; low-certainty evidence) or clinically relevant non-major bleeding events (RR 1.76, 95% CI 0.90 to 3.42; 2 studies, 389 participants; I² = 1%; low-certainty evidence) between three months or more of treatment and six weeks of treatment. There were no reports for overall mortality or PE and major bleeding-related deaths.

AUTHORS' CONCLUSIONS

Our review found a benefit for people with distal DVT treated with anticoagulation therapy using VKA with little or no difference in major bleeding events although there was an increase in clinically relevant non-major bleeding when compared to no intervention or placebo. The small number of participants in this meta-analysis and strength of evidence prompts a call for more research regarding the treatment of distal DVT. RCTs comparing different treatments and different treatment periods with placebo or compression therapy, are required.