Significance of deep vein thrombosis

Deep vein thrombosis (DVT) is a potentially life-threatening condition that affects more than 300,000 individuals in the United States annually.

Thrombosis of an iliofemoral vein accounts for approximately 25% of all lower extremity DVTs and is associated with an increased risk of pulmonary embolism (PE), limb malperfusion, and post-thrombotic syndrome (PTS) when compared to DVT that occurs below the knee.

Predisposing conditions of Iliofemoral deep vein thrombosis

Iliofemoral DVT typically affects patients with an anatomic predisposition to venous stasis.

In a retrospective study of 56 patients presenting with acute iliofemoral DVT, 45 (84%) patients had evidence of iliac vein compression on CT venography.

The most well described scenario involves compression of the left iliac vein between the right iliac artery and a vertebral body (May-Thurner syndrome).

However, extrinsic compression of an iliac vein can occur in either leg and through a variety of mechanisms, including pelvic malignancy or trauma.

In addition to an anatomic predisposition to venous stasis, the majority of patients with iliofemoral DVT have at least one additional risk factor for venous thrombosis.

Endothelial injury and hypercoagulability, along with stasis, comprise Virchow’s triad of thrombogenesis.

Common examples include the postoperative state, prolonged immobility (e.g., travel, hospitalization), malignancy, pregnancy, and inherited hypercoagulable conditions.

Clinical manifestations of Iliofemoral deep vein thrombosis

Patients with acute DVT commonly present with lower extremity pain and swelling.

Physical exam may reveal a palpable cord, ipsilateral edema, erythema, or venous distension.

Rarely, patients with DVT may present with evidence of arterial insufficiency due to massive iliofemoral DVT. Known as phlegmasia cerulea dolens, this life-threatening condition occurs as a consequence of severe venous obstruction. As swelling progresses, compartment syndrome and arterial compromise can lead to venous gangrene. Prompt venous recanalization via catheter-directed thrombolysis and thrombectomy is indicated to prevent limb loss, circulatory collapse, and death.

Long-term complications of DVT include persistent lower extremity edema, venous claudication, hyperpigmentation, and ulceration – known collectively as PTS. Mediated by venous hypertension and valve incompetence arising from persistent iliofemoral obstruction, these sequelae affect up to 50% of patients following an incident iliofemoral DVT and are associated with a reduced quality of life and increased health care expenses.

In a retrospective study of 26,958 patients with DVT or PE, the development of PTS was associated with a 32% increase in annualized total health care costs, due in large part to outpatient resource utilization and the management of venous ulcers.

Diagnosis of Iliofemoral deep vein thrombosis

Many patients who present with lower extremity pain and swelling do not have DVT.

Stratifying patients according to their pretest likelihood of having this disease is, therefore, a fundamental element of a cost-effective approach to diagnosis.

The Wells score includes nine variables to determine whether a patient has a low, moderate, or high probability of having a DVT.

In patients with a low or moderate pretest probability of having a DVT, a negative D-dimer effectively rules out the diagnosis.

Current guidelines favor D-dimer testing in these populations, although ultrasound may be used when comorbid conditions confound the interpretation of a positive result. In patients with high probability of DVT.