Mechanical Thrombectomy for Iliofemoral Deep Venous Thrombosis Complicated by Phlegmasia Cerulea Dolens in a Pregnant Patient With May-Thurner Syndrome: A Case Report.

This case report describes a 35-year-old, G1P0 patient at 24 weeks and three days of gestation with no significant medical history, who presented with edema and discoloration of the left lower extremity, accompanied by left inguinal pain. These symptoms followed three days of low back pain radiating to the same region. On physical examination, findings were suggestive of deep venous thrombosis (DVT). Point-of-care ultrasound and venous Doppler confirmed thrombosis extending from the left proximal femoral vein to the left external iliac vein. To further assess the thrombus burden and anatomical extent, a computed tomography (CT) venography was performed following informed consent. CT venography demonstrated a thrombus extending from the left external iliac vein through the left common iliac vein to its junction with the inferior vena cava (IVC). The left common iliac vein was notably compressed by the overlying right common iliac artery, causing retrograde venous congestion and supporting the diagnosis of iliofemoral DVT secondary to May-Thurner syndrome. After thorough multidisciplinary discussion and risk-benefit evaluation, and with the patient's informed consent, an interventional approach was undertaken. Initial management included anticoagulation with enoxaparin, partial mechanical thrombectomy, and placement of an IVC filter. On the second day post-procedure, the patient developed acute worsening of edema, progressive skin discoloration, decreased temperature of the affected limb, and diminished palpable pulses, raising concern for arterial compromise consistent with phlegmasia cerulea dolens. In response, an extensive mechanical thrombectomy was promptly performed, resulting in improved distal venous outflow and clinical stabilization. This case demonstrates that, in selected pregnant patients with extensive or complicated iliofemoral DVT, mechanical thrombectomy within a multidisciplinary care framework can be a safe and effective therapeutic option to achieve rapid symptom relief and potentially reduce short- and long-term complications.