Iliac vein compression syndrome (IVCS), also known as May–Thurner or Cockett syndrome, was first described in 1957 [1] and is defined as extrinsic compression of the left common iliac vein (LCIV) between the right common iliac artery (RCIA) and the lumbar vertebra [2,3]. Sustained compression and trauma caused by the pulsatile force of the overlying artery can damage the venous wall, cause intimal hyperplasia, and lead to a degree of shear between the anterior and posterior walls of the vein. The resulting epithelial damage, which induces collagen and elastin deposition, can cause venous fibrosis and the formation of webs/bands inside the venous lumen, leading to stasis and venous hypertension [2,3].

IVCS commonly affects females in their third to fifth decade of life. Although asymptomatic in most patients, it mostly presents with venous hypertension when manifested, which can lead to venous insufficiency, left lower extremity swelling, varicose veins, venous claudication, hyperpigmentation, or venous ulcers [3]. Computed tomography (CT) and magnetic resonance venography have >95% sensitivity and specificity for diagnosing IVCS [4-7].

Deep venous thrombosis (DVT) is one of the most severe complications of IVCS. When discussing DVT, the most feared complication is phlegmasia cerulea dolens (PCD), a medical emergency that threatens the lower limb and requires quick intervention to prevent irreversible limb ischemia and potentially fatal necrotizing fasciitis [8]. This article reports a case of PCD as the first manifestation of IVCS and discusses the therapeutic considerations.

The study was approved by the Institutional Review Board of the Pontifícia Universidade Católica do Rio Grande do Sul (IRB no. 27075219.6.0000.5336). Informed consent was obtained from the patient to publish the case report and accompanying images.

A 33-year-old female with an unremarkable past medical history besides being overweight and a tobacco and oral hormonal contraceptives user presented at the emergency department with acute onset of edema, coldness, cyanosis, hypoesthesia, and decreased motricity of her left lower limb with approximately 18 hours of evolution (Fig. 1). This clinical scenario was preceded by lower back pain for 36 hours. Palpation of the arterial pulses on the left lower limb was hampered by edema, and the emergency room staff could not palpate any arterial pulse. In contrast, arterial examination of the contralateral limb was normal. With the provisional diagnosis of acute arterial occlusion, therapeutic-dose intravenous heparin infusion was initiated, and angio-CT was performed. The angio-CT revealed extensive acute thrombosis of the left iliac and femoropopliteal veins associated with compression of the LCIV by the RCIA (with a 2.6-mm distance between the posterior arterial wall and the anterior aspect of the vertebral body at the level of the vein crossing) (Fig. 2). No evidence of pulmonary embolism was observed.

Figure 1. The photographs showed the initial clinical presentation of phlegmasia cerulea dolens (left) and improved limb perfusion after surgical thrombectomy (right).

Figure 2. Computed tomography scans revealed left common iliac vein compression and extensive thrombosis of the iliofemoral segment.

The patient was promptly transferred to the surgical ward, and an open iliofemoral venous thrombectomy was performed via a left inguinal approach by the vascular surgery team. Once the saphenofemoral junction and the common femoral vein were identified, a n° 05 embolectomy catheter (Fogarty catheter), which was the largest embolectomy catheter available at that moment, was inserted through a common femoral transverse venotomy and advanced into the iliac veins with the removal of a large amount of fresh thrombus (Fig. 3). During the procedure, difficulty was observed in progressing the catheter to >18 cm from the venotomy level. Thrombectomy of the saphenofemoral junction, the proximal third of the great saphenous vein, and the deep femoral vein was also performed, with adequate bleeding from the deep femoral vein to serve as inflow for the iliac segment. No attempt was made to remove the femoral vein thrombus because of the sufficient flow from the deep femoral vein. Due to the unavailability of a larger embolectomy catheter and the possibility of residual thrombus in the iliac vein and inferior vena cava (IVC), an additional loco-regional single-injection of a thrombolytic agent (10 mg of alteplase, Actilyse; Boehringer) was infused in the left iliofemoral axis via venotomy using a n° 10 aspiration catheter. Due to the marked swelling of the left lower limb and muscular compartments, decompression of the anterior compartment of the thigh and the anterior and lateral compartments of the calf was performed through fasciotomy. At the end of the procedure, the patient showed significant improvement in left lower limb perfusion with the cyanosis remission (Fig. 1).

Figure 3. A photograph showed a large amount of fresh thrombus removed with a Fogarty catheter.

The patient was maintained on therapeutic-dose intravenous heparin infusion (80 units/kg+18 units/kg/h to maintain activated partial thromboplastin time between 1.5 and 2x baseline), and 48 hours after the surgical procedure, she was taken to the interventional suite for additional studies and treatment. We waited 48 hours to perform additional procedures because of the logistics of the endovascular device supply.

Under local anesthesia and conscious sedation, ultrasound-guided venous accesses were obtained on both limbs, with a puncture of the left great saphenous vein (GSV) at the proximal tight with a 08-F–11-cm sheath system and puncture of the right femoral vein with a 05-F–11-cm sheath system. Phlebographies of the iliac veins and IVC confirmed a stenosis >50% at the LCIV with no major other stenosis at the iliac segment. Following the crossing of the lesion with a 0.035-inch stiff 260-cm guidewire (Glidewire; Terumo), balloon predilatation for vessel preparation with a 12 mm×40 mm angioplasty balloon catheter (Advance 35LP; Cook Medical) and primary implantation of 12 mm×60 mm (Zilver Flex; Cook Medical)+12 mm×60 mm (Zilver Flex) self-expanding stents in an overlapping fashion was performed at the level of the common iliac and proximal external iliac veins. Control phlebography showed adequate final results (Fig. 4).

Figure 4. Phlebography demonstrated iliac vein compression (left) and improved stenosis after stent placement (right).

The patient had a satisfactory postoperative evolution, with no significant bleeding or other complications. The fasciotomy sites were primarily closed after 16 days. The patient was discharged 18 days after admission and was placed on rivaroxaban 20 mg daily, which she still used after 18 months at full dose. We decided to maintain the patient on an anticoagulation regimen indefinitely (probably lifelong) because of the dramatic clinical presentation at admission and the low presumed risk of bleeding related to the use of rivaroxaban. The patient recovered without significant edema or other signs of post-thrombotic syndrome. Venous Doppler ultrasound at 12-month follow-up showed patent stents without evidence of significant residual thrombus or obstruction in the ilio-femoral-popliteal segment.

PCD is an uncommon complication of DVT with IVCS, and associated with a high incidence of amputation (12%-50%) and mortality (20%-40%) [9]. This report presents a patient successfully treated with surgical thrombectomy and stent placement 36 hours after symptom onset.

There are no evidence-based protocols to guide treatment of PCD owing to its low prevalence. Among therapy options, catheter-directed thrombolysis [10-15], percutaneous thrombectomy [16,17], and surgical thrombectomy [18,19] can be highlighted.

Early recognition and intervention are prognostic of good limb and survival outcomes, and the rapid restoration of venous outflow is critical. Sometimes, the clinical presentation is similar to an acute arterial occlusion, and its prompt differentiation is crucial to guide examinations and therapy.

Anticoagulation is an initial measure to prevent thrombus propagation [10-17,19]. Combining anticoagulation with a thrombus removal strategy, as performed in our case, appears to be the best option for treating extensive DVT involving the iliac segment. Surgical thrombectomy is an option for rapid restoration of venous outflow. It can rapidly restore venous flow to relieve venous congestion with a low risk of bleeding and hemolysis, sometimes associated with endovascular devices for thrombolysis and thromboaspiration. Also, endovascular devices have cost associated problems in their use and are not always available. Furthermore, it should be noted that endovascular therapy is usually indicated for less severe presentations, whereas for a profoundly ischemic limb, as in our case, surgical thrombectomy seems to be a better option [20].

Iliac vein compression does not always require treatment. However, in the context of a thrombus removal strategy for acute extensive iliofemoral DVT, treatment of IVCS must be performed to minimize the risk of recurrence and post-thrombotic syndrome [2]. In our case, we did not use dedicated venous stents or treat the compression at the time of thrombectomy because of the unavailability of a hybrid endovascular suite. This approach involving two interventions separated by a short time interval bridged with anticoagulation shows the feasibility of a two-stage procedure without compromising the end result. However, we should highlight that this is not the ideal approach. Ideally, we should always perform the chosen thrombus removal strategy and treat the associated stenotic lesions that could have contributed to the thrombosis or that can promote re-thrombosis during or immediately after the procedure. However, when this cannot be done, the patient must be maintained under strict anticoagulation to minimize re-thrombosis risk and perform additional intervention as soon as possible. Nevertheless, our report shows that the unavailability of an endovascular or hybrid vascular suite should not preclude or delay an intervention, which must be performed promptly in cases with a risk of limb loss, such as ours. We showed that an open surgical approach such as venous thrombectomy, rarely indicated nowadays, could promote fast limb decongestion and avoid limb loss. Notably, this procedure can also be performed in a hospital with fewer therapeutic resources; the patient can be transferred to an institution with access to endovascular therapy after surgical thrombectomy.

In our endovascular approach, we used ultrasound-guided GSV puncture for access. With the previous surgical removal of the thrombus located at the common femoral and deep femoral veins (with identification of adequate inflow from them), we considered the inflow previously obtained as adequate. We aimed to perform an additional intervention only at the iliac vein to minimize the risk of re-thrombosis and post-thrombotic syndrome related to the presence of common iliac compression and the possibility of residual thrombus. There is no substantial evidence in the literature to support an attempt regarding additional thrombus removal from the femoropopliteal segment as in our patient. Therefore, we chose the GSV as the vascular access site because we did not plan to perform femoropopliteal thrombectomy and/or thrombolysis. The proximal GSV has a relatively superficial course and, in our patient, had an adequate caliber to accommodate an 08-F sheat. As a GSV has a more superficial location compared to deep veins, it is easier to compress and can be ligated in the presence of a bleeding complication. In our case, we were treating an obese patient and anticipated the possibility of placement of a multihole catheter for additional thrombolytic therapy to clear residual thrombus of the iliac level if needed. Furthermore, we desired to avoid direct manipulation of the previous surgical site and the possibility of puncturing the previous suture at the common femoral vein.

It is essential to evaluate the need for fasciotomy as an adjuvant procedure in cases of extensive DVT, as it is sometimes necessary to relieve marked tissue hypertension associated with venous congestion.

Given the severity of the presentation and the lack of evidence regarding the provision of anticoagulation, we decided to maintain extended full-dose anticoagulation. After 1 year of follow-up, the affected limb had preserved function and no signs of post-thrombotic syndrome. In summary, we describe a successful staged strategy for treating PCD in patients with IVCS and DVT. The lack of an endovascular or hybrid vascular suite should not preclude surgical thromboembolectomy to prevent limb loss and mortality, and staged treatment may be an option.

None.

The authors have nothing to disclose.

Concept and design: FEF, APDM, LHB, SCP. Analysis and interpretation: APDM, LHB, AAS. Writing the article: FEF, LDGP, APDM, LHB, AAS. Critical revision of the article: ORP, AAS, SCP. Final approval of the article: all authors. Statistical analysis: APDM, AAS. Overall responsibility: SCP.