Iliofemoral Deep Vein Thrombosis Management and Treatment

Abstract

The treatment of acute deep vein thrombosis (DVT) of the lower extremity is dependent on the severity of symptoms. Mild symptoms may be treated with anticoagulation alone. However, moderate to severe symptoms in the setting of iliofemoral venous obstruction, that persist or worsen, should be treated surgically to prevent post-thrombotic syndrome. With current technological advances in vascular surgery, many novel endovascular devices have been developed with highly successful thrombolysis and thrombectomy outcomes. But if percutaneous methods fail, open surgical treatment remains an option with procedures such as open venous thrombectomy and vein bypass. This chapter reviews the workup, diagnosis, and management of acute lower extremity DVT with an emphasis on the surgical treatment of iliofemoral DVT.

1. Introduction

Thrombosis is a disease process in which blood clots form in the arterial and/or venous systems. Venous thrombosis, also referred to as venous thromboembolism (VTE), has an incidence of approximately 1–2 per 1000 person-years in Europe and the USA [1]. VTE most commonly presents as deep vein thrombosis (DVT) of the lower extremity and pulmonary embolism. In the USA, the incidence of lower extremity DVT exceeds 350,000 cases annually with a 6% mortality at 30 days [2]. The burden of lower extremity DVT not only includes substantial public health costs but also significant personal costs that may severely impair quality of life. This chapter provides an overview of the diagnosis and management of lower extremity DVT with an emphasis on the surgical treatment options for iliofemoral DVT.

2. Etiology and anatomy

Virchow’s triad of vascular endothelial injury, stasis of flow, and presence of a hypercoagulable state, increases the risk of lower extremity DVT. When a patient has any component of these three factors, the etiology of the DVT is characterized as provoked by an identifiable transient or persistent risk factor such as recent surgery, immobilization, travel, malignancy, pregnancy, trauma, oral contraceptives, hereditary conditions, or advanced age. DVT is considered unprovoked in the absence of identifiable risk factors [3]. Thrombus is defined as acute if it has been present for 14 days or less. The treatment of DVT has different anatomic considerations. The deep veins of the lower extremity are classified as either proximal or distal. Proximal DVT is located in the popliteal, femoral, and iliac veins. This is commonly referred to as iliofemoral DVT. While isolated distal DVT involves thrombus only below the knee in the calf veins, which include the peroneal, posterior tibial, anterior tibial, and muscular veins (gastrocnemial and soleal) [3].

3. Diagnosis

Patients with lower extremity DVT may present with physical exam findings of unilateral lower extremity swelling, erythema, warmth, and tenderness to palpation. The most common symptom is calf pain [4]. The Wells score calculates the likelihood and pre-test probability that a patient has a DVT. Additionally, a measurement of an elevated D-dimer, which is a biomarker produced by the degradation of cross-linked fibrin by plasmin, has a high sensitivity and poor specificity for positively diagnosing acute DVT. Its results are limited in patients with recent surgery, malignancy, pregnancy, and trauma due to the physiologic changes in these conditions. Therefore, D-dimer results should be interpreted in conjunction with additional testing [4].

Duplex ultrasound is the gold standard imaging study for diagnosing DVT as it is noninvasive, portable, cost-effective, and lacks radiation. Positive findings for acute DVT include non-compressible vein, distended venous diameter, hypoechoic thrombus (darker), absent blood flow, absent collaterals, and absent flow augmentation with distal compression (Figures 1 and 2) [2]. CT venography (CTV), while it is as accurate as duplex ultrasound in diagnosing proximal lower extremity DVT, it is beneficial in further assessing the anatomy and patency of the inferior vena cava and pelvic veins, detecting abdominal and pelvic malignancy, and visualizing extrinsic compression of vascular structures. Additional studies such as MR venography (MRV) may provide additional information about adenopathy, soft tissues masses, or malignant invasion of vascular structures that may cause venous thrombosis [5]. The use of CTV or MRV as adjunct studies must have cautious consideration in patients with renal dysfunction.

Figure 1.

Duplex ultrasound showing right saphenofemoral junction with thrombus in the common femoral vein (CFV). The CFV is distended and noncompressible. CFA, common femoral artery.

Figure 2.

Color doppler of the right common femoral vein (CFV) with absence of blood flow. CFA, common femoral artery.

4. Anatomic causes of iliofemoral deep venous thrombosis

4.1 May-Thurner syndrome

May-Thurner syndrome refers to non-malignant iliac vein stenosis caused by compression of the left common iliac vein by the right common iliac artery against the lumbar vertebra [6]. Symptoms present as swelling and pain of the left lower extremity that increases in severity with prolonged standing and activity, also known as venous claudication. Symptoms improve with rest and elevation of the left leg. Varicose veins and venous ulcers may also occur [6]. Young women, especially those who are postpartum, multiparous, or using oral contraceptives are typically affected. However, most patients with May-Thurner anatomy are asymptomatic and do not require treatment [7].

These patients are at much higher risk of DVT originating in the iliac vein. Venous duplex is used to identify the thrombus. However, diagnosis of May-Thurner syndrome requires a venogram or intravascular ultrasound (IVUS) (Figure 3) [7, 8]. The VIDIO trial compared venography versus IVUS for diagnosing iliac vein stenosis and concluded that IVUS is more sensitive [9]. Therefore, IVUS should be considered in all cases where May-Thurner syndrome is suspected.

Figure 3.

(A) Intravascular ultrasound demonstrating compression of the left common iliac vein (LCIV) by the right common iliac artery (RCIA). (B) Improvement in stenosis of the LCIV after stent placement. Adapted from “MayThurner Syndrome: old acquaintance, new perspective,” by V. Boc, a Boc, and M.Kozak, 2017, mar 20, wiener Klinische Wochenschrift, 129, p 362-365. Copyright 2017 by wiener Klinische Wochenschrift [8].

While asymptomatic patients do not require surgical treatment, symptomatic lesions with >50% cross sectional diameter reduction require treatment with stent placement in the left common iliac vein [7]. If iliofemoral DVT is present, thrombolysis and/or thrombectomy is performed first. If endovascular methods fail or are contraindicated, open deep vein bypass procedures may be required as discussed later in this chapter.

4.2 Congenital iliocaval disease

Congenital occlusion or absence of the inferior vena cava (AIVC) is rare disease with an incidence of approximately 0.3% to 0.5% in the general population. The disease pathology creates a low-flow state, which can then result in iliofemoral DVT. It remains largely undiagnosed and asymptomatic, but when diagnosed, it is most commonly found in young males with idiopathic bilateral lower extremity DVT [10].

The embryogenesis of the inferior vena cava (IVC) begins around week 6. The IVC is formed by primitive veins made up of the supracardinal, subcardinal, and postcardinal veins. The primitive veins and collaterals regress during development to create the IVC. IVC anomalies are caused by a disruption in this process. The most common anomalies include left IVC, double IVC, atresia or agenesis of the IVC, azygos or hemiazygos continuation of the IVC [10].

AIVC is typically asymptomatic and incidentally found on imaging studies. Symptomatic patients usually present with bilateral leg swelling, signs of chronic venous insufficiency such as discoloration or venous wounds, and abdominal wall varicosities [10].

Venous duplexes of the pelvis and lower extremity are the initial imaging studies of choice. A large number of collaterals and absence of iliocaval segments may be identified. Confirmatory imaging with CTV or MRV is required for diagnosis (Figure 4) [10, 11].

Figure 4.

CT scan coronal view demonstrating absent infrarenal inferior vena cava in the portal venous phase. Adapted from absent infrarenal inferior vena cava by Y. Weerakkody and S. mirza, 2020, Radiopaedia. Retrieved Jun, 30, 2023 Available from: https://radiopaedia.org/articles/absent-infrarenal-inferior-venacava?lang=us#article-images. Copyright 2020 by Radiopaedia [11].

Asymptomatic patients do not require surgical treatment. Patients with mild symptoms and acute iliofemoral DVT are treated with potential lifelong anticoagulation if there is no plan for reconstruction. If symptoms are severe, thrombolysis and/or thrombectomy is typically required. If symptoms persist and become debilitating, patients may be offered open surgical or complex endovascular iliocaval reconstruction if valvular competence has been confirmed in the peripheral veins. Open venous reconstruction may use aortic or IVC homografts. Endovascular techniques have trialed stenting of the azygos vein outflow. Both open and endovascular interventions are complex and rare, and careful consideration must be made when choosing to perform such interventions [10].

5. Medical treatment

Patients diagnosed with lower extremity DVT are treated based on symptom severity, risk factors, and the anatomic location of the DVT. The purpose of treating acute DVT is to stabilize the developing thrombus to prevent extension or embolization and to reduce the morbidity and mortality associated with DVT. The following recommendations are based off of the 2021 American College of Chest Physicians (CHEST) guidelines. Patients with proximal lower extremity DVT with minimal to no symptoms should be treated with therapeutic anticoagulation. Recommended treatment duration is 3 months for DVT provoked by a transient or persistent risk factor and extended treatment duration of greater than 3 months for unprovoked DVT with low to moderate risk of bleeding. An inferior vena cava (IVC) filter is not recommended in addition to therapeutic anticoagulation. However, an IVC filter is indicated for patients with proximal DVT with a contraindication to anticoagulation such as active bleeding, coagulopathy, recent intracranial hemorrhage, major trauma, recent major surgery [12, 13].

Patients with an isolated distal DVT without severe symptoms or risk factors for extension, serial duplex ultrasound in 2 weeks is recommended. If repeat imaging shows no thrombus extension, no treatment is indicated. But if repeat imaging shows extension of thrombus confined to the distal veins or extending into the proximal veins, therapeutic anticoagulation should be initiated. If patients with isolated distal DVT have severe symptoms or risk factors for extension, anticoagulation should be initiated immediately [12].

6. Anticoagulation

Therapeutic anticoagulation is the mainstay of medical treatment for lower extremity DVT. In the past, there were limited treatment options, and management with vitamin K antagonists (VKA) was often the agent of choice, which requires frequent laboratory monitoring and bridging with unfractionated heparin (UFH) or low molecular weight heparin (LMWH). But now several agents exist that allow for simpler and more accessible outpatient management of DVT [2].

In selecting the appropriate anticoagulation agent, a review of risk factors for bleeding must be performed to assess for factors such as advanced age, risk of falls, renal or hepatic disease, malignancy, and prior stroke. Direct-acting oral anticoagulants (DOACs) are now the anticoagulation of choice in lower extremity DVT. These include inhibitors of factor Xa (apixaban, rivaroxaban, edoxaban) and IIa (dabigatran). DOACs have equivalent efficacy to VKA without the associated increased bleeding risk [2]. Previously, those with cancer-associated thrombosis were treated most commonly with LMWH, but based on the results of the SELECT-D trial, recent guidelines from the National Comprehensive Cancer Network (NCCN) have now also recommended anti-Xa inhibitors for monotherapy [2, 14]. Parenteral LMWH is the preferred agent in patients with poor or no oral intake. Additionally, LMWH is the preferred agent in pregnancy, as warfarin, a VKA, is teratogenic and the safety profile of DOACs in pregnancy has not been well studied [2].

7. Post-thrombotic syndrome

Post-Thrombotic Syndrome (PTS) refers to the signs and symptoms that result from acute DVT. Patients develop ambulatory venous hypertension and venous insufficiency due to chronic luminal venous obstruction and valvular incompetence. Patients with massive iliofemoral DVT are at high risk of developing PTS because the single venous outflow to the lower extremity is occluded [15]. Symptoms of chronic post-thrombotic venous disease are leg pain, swelling, vein dilation, skin pigmentation, and venous ulcerations [16]. The goal of surgical intervention is to eliminate the DVT to preserve venous valve function and prevent consequences of PTS.

The ATTRACT trial studied patients with symptomatic proximal DVT and stratified them into two groups, iliofemoral and femoral-popliteal DVT. Both groups were randomized into treatment with either anticoagulation alone or pharmacomechanical catheter-directed thrombolysis (PCDT) plus anticoagulation. Results at 2 years showed that in the iliofemoral DVT cohort, the PDCT treatment arm did not necessarily reduce the overall occurrence of PTS, but it did reduce severity of PTS and improved quality of life [17]. Kearon et al. performed a separate subgroup analysis of the femoral-popliteal cohort and showed that there was no difference in PTS occurrence or severity between the two treatment arms [18].

8. Surgical treatment

In most situations, anticoagulation alone is sufficient to treat acute lower extremity DVT. But in certain circumstances, DVT can lead to severe conditions such as phlegmasia, venous gangrene, or post-thrombotic syndrome (PTS), which necessitate surgical intervention. These complications are typically the result of acute massive iliofemoral DVT. While patients with DVT are at risk of pulmonary embolism, the goal of surgical intervention is not to prevent pulmonary embolism but to prevent limb loss and PTS [15].

Phlegmasia alba dolens (PAD) presents as a swollen and painful white-colored lower extremity, which is differentiated from phlegmasia cerulea dolens (PCD) that presents as a swollen and painful, blue-colored lower extremity (Figure 5). Unlike PAD, PCD typically involves the superficial venous drainage system, and accumulation of deoxyhemoglobin in the dermal and subdermal venous plexuses results in cyanosis. This increased venous hypertension can progress to venous gangrene, typically found in patients with underlying cancer or disseminated intravascular coagulation. Severe venous hypertension with associated swelling of the leg may cause obstruction of arterial inflow, resulting in a threatened limb. PCD and venous gangrene require urgent surgical intervention [19].

Figure 5.

Right lower extremity iliofemoral DVT causing phlegmasia.

For patients diagnosed with acute iliofemoral DVT who present with moderate to severe pain and leg swelling without signs of phlegmasia or venous gangrene, it is reasonable to monitor for improvement of symptoms on therapeutic anticoagulation. If symptoms persist without improvement, and the patient has good functional status, life expectancy greater than 1 year, and low bleeding risk, proceeding with surgical intervention within 14 days of symptoms is recommended. Intervention on DVT’s that have been present for greater than 14 days has lower technical success [20].

9. Endovascular thrombolysis and thrombectomy devices

9.1 Catheter-directed thrombolysis (CDT)

Using the standard Seldinger technique through a popliteal vein approach in the prone position, a 4 or 5 Fr multisidehole Uni-Fuse infusion catheter is placed within the venous thrombus (Figure 6) [21]. The 4 Fr infusion catheter is available in 90 and 135 cm lengths while the 5 Fr is available in 45, 90, and 135 cm lengths. Both have infusion slit patterns between 2 to 50 cm and are compatible with 0.035-inch wires. Thrombolytic agents, including tissue plasminogen activator (tPA), recombinant tissue plasminogen activator (r-tPA), or tenecteplase (TNK) are commonly used without significant differences in outcomes [22]. Recommended doses for continuous catheter-directed thrombolysis infusion are 0.5-1.0 mg/hour for tPA, 0.25-0.75 units/hour for r-tPA, 0.25–0.5 mg/hour for TNK. Continuous heparin is also delivered at 500 units/hour through the sheath. Patients must return to the operating room within 24 hours for repeat venography to assess lysis outcomes. The main advantage of CDT is that it limits systemic lytic exposure and maximizes effect of the drug at the targeted location. However, intensive care unit (ICU) stays can range from 24 to 72 hours. These contribute to the overall high costs of admission, including the expensive drug costs. Significant bleeding complications include 45% of insertion site bleeding, 33% intracranial bleeding, and 22% of patients that require transfusions [23].

Figure 6.

Uni-fuse catheter. Adapted from “Uni-fuseTM infusion catheter,” by Angiodynamics. Retrieved July 6, 2023 [21].

9.2 Ultrasound-accelerated thrombolysis

The EkoSonic (EKOS) endovascular system uses CDT in combination with low-power, high frequency (2 MHz) ultrasound to lyse clot. The three parts include the multisidehole infusion catheter, ultrasound core wire, and control unit. The catheter is compatible with 0.035-inch wires and available in treatment lengths between 6 and 50 cm. The device consists of three infusion channels for drug delivery. When the control unit is activated, ultrasound waves are delivered to the core wire transducers which are then transmitted through the catheter to lyse thrombus. Normal saline acts as a coolant that is infused through the central lumen to dissipate heat. The added affect of ultrasound increases thrombus permeability by reducing the diameter of fibrin strands and increasing the number of fibrin strands exposed to the thrombolytic agent [24]. The main advantages of ultrasound-accelerated thrombolysis are the low incidence of bleeding complications (3.8%) and lower median lytic infusion times of 22 hours. This decreases ICU length of stay and perioperative risks compared to CDT alone [25]. However, it does not eliminate the high drug costs, overall bleeding risks, or ICU requirements. The BERNUTIFUL trial studied patients with iliofemoral DVT treated with the EKOS CDT alone versus the EKOS CDT with ultrasound. The results showed that the addition of ultrasound did not reduce thrombus load [26]. Therefore, the use of ultrasound-accelerated thrombolysis is up to the discretion of the surgeon (Figure 7) [27].

Figure 7.

EKOS endovascular system. Adapted from “EKOS Endovascular System” by Boston Scientific. Retrieved July 6, 2023 [27].

9.3 Percutaneous mechanical thrombectomy

Percutaneous mechanical thrombectomy is a catheter-based therapy that directly disrupts the thrombus [28, 29]. The Inari ClotTriever catheter features a nitinol coring element and a braided collection bag (Figure 8) [30]. It is designed to core and collect clot from the ClotTriever sheath, which is available in 13 and 16 Fr. The sheath features a self-expanding nitinol mesh funnel to facilitate clot retrieval and a large bore side port for rapid aspiration. The FlowSaver is a filter system that allows for aspirated blood to be returned back to the patient, decreasing blood loss. The catheter provides approximately 30% greater radial force for better wall apposition. Thus, this improves thrombus engagement to treat the full range of acute to chronic clot [30]. Additionally, the 20 Fr Protrieve sheath, features a wall apposing funnel designed to trap emboli during complex DVT or IVC thrombectomy procedures and prevent propagation of pulmonary emboli (Figure 9) [30]. It is compatible with the ClotTriever system. Advantages of this device include no thrombolytic use, low blood loss, no ICU requirements, and no large accessory equipment is required [30]. An example venogram demonstrates pre-intervention and post intervention images of a patient who underwent mechanical thrombectomy performed with Inari ClotTriever (Figure 10).

Figure 8.

(A) ClotTriever catheter. (B) ClotTriever sheath. Adapted from “Clottriever BoldTM” by inari medical. Retrieved July 7, 2023 [30].

Figure 9.

Protrieve sheath. Adapted from “Clottriever BoldTM” by inari medical. Retrieved July 7, 2023 [30].

Figure 10.

(A) Pre-intervention venography showing left iliofemoral DVT. (B) Post-intervention venography showing recanalization of the left common femoral vein and external iliac vein. Mechanical thrombectomy performed with inari ClotTriever.

9.4 Aspiration thrombectomy

The simplest form of percutaneous aspiration thrombectomy is performed by moving a catheter over a wire and aspirating thrombus with the negative pressure of a syringe. However, these techniques show low success rates when used as standalone therapies [31]. Penumbra’s Indigo System catheter uses a separator-assisted mechanical extraction of thrombus with constant aspiration (Figure 11) [32]. It is currently available in 6, 7, 8, and 12Fr sheaths. They are compatible with 0.014 or 0.038 wires with 50–150 cm working lengths. The Lightning intelligent aspiration tubing contains a valve to provide continuous aspiration within the clot and intermittent aspiration within patent blood flow. The separator is an adjunct device advanced and retracted through the catheter at the proximal margin of the occlusion to facilitate clearing of the thrombus from the catheter tip [32]. The advantages of this device is that it does not use lytic therapy which eliminates ICU requirements. However, it does have the risk of high blood loss [33].

Figure 11.

Penumbra system. Adapted from Vascupedia. Retrieved July 7, 2023 [32].

9.5 Rheolytic thrombectomy

Rheolytic thrombectomy uses high-velocity infusate to lyse clot. The AngioJet Thrombectomy System uses a catheter and a console. High-velocity saline infusion jets from the catheter lyse thrombus and create a vacuum effect to redirect flow and aspirate fragmented thrombus into outflow channels behind the catheter tip. The catheter is compatible with an 0.035 inch wire and is available in working lengths of 60, 100, and 120 cm. Thrombolytics may be initially infused into the clot prior to aspiration through Power Pulse lytic delivery. Superior results of thrombus burden removal are noted with the use of thrombolytics (Figure 12) [34, 35].

Figure 12.

AngioJet catheter. Adapted from “AngioJetTM peripheral thrombectomy system” by Boston Scientific. Retrieved July 7, 2023 [34].

Similarly, the JETi Hydrodynamic Thrombectomy System uses a catheter and saline drive unit. The device contains an internal saline jet to break up and remove thrombus within the catheter tip. The HyperPulse Fluid Delivery system can selectively infuse lytic therapy. This device is available for 6 and 8 Fr sheaths. Venous patency has been shown to be restored in 90% of patients and valvular function found to persist in 88% of patients in a 6-month follow-up assessment (Figure 13) [36, 37].

Figure 13.

JETi hydrodynamic thrombectomy catheter. Adapted from “Jeti hydrodynamic thrombectomy system” by Abbott. Retrieved July 7, 2023 [36].

Both devices may be used without lytic drugs, which is beneficial in patients where thrombolytics are contraindicated. If lytic agents are used, targeted therapy limits systemic distribution and thus decreases bleeding risks. In some instances, stretching of vein wall receptors possibly leads to bradyarrhythmias and/or asystole during rheolytic therapy [38]. Pancreatitis has also been linked to rheolytic therapy in rare occurrences possibly due to hemolysis [39].

9.6 Trellis-8 peripheral infusion system

The Trellis-8 device uses thrombolytics to breakdown clot. It consists of a catheter with a proximal and distal occlusion balloon with a dispersion wire that oscillates in the treatment segment to increase thrombus permeability (Figure 14) [40]. The device uses a catheter, dispersion wire, and integral drive unit. The catheters are available in 80 or 120 cm lengths, with treatment distances between the balloons of 10, 15, 0r 30 cm. 5 to 10 mg of lytic is infused within the thrombus in between the balloons. Oscillation disperses the lytic and promotes clot lysis. After 5 to 15 minutes, the distal balloon is deflated and aspiration removes fragmented thrombus. During aspiration, the proximal balloon remains inflated to prevent clot embolization. CDT leads to 79% of patients with at least 50% clot lysis, whereas Trellis-8 leads to 93% of patients achieving this clot lysis with reduced bleeding complications [41, 42]. Studies showed 80% of clot resolution in a single setting, with 88% venous patency at the 6-month follow-up [37]. This system limits systemic lytic exposure and uses lower drug dosages, which leads to lower costs, bleeding complications, and ICU stays [38, 39].

Figure 14.

Trellis-8 peripheral infusion catheter. Adapted from “Clinical and Economic Evaluation of the Trellis-8 Infusion Catheter for Deep Vein Thrombosis” by Hilleman D, Razavi M from Abbott. Retrieved July 23, 2023 [40].

10. Open surgical procedures

10.1 Open venous thrombectomy

Open surgical treatment of iliofemoral DVT is typically offered to patients if endovascular methods fail or are contraindicated [43, 44]. But advanced percutaneous techniques have high success rates and are the initial surgical management of choice. Open venous thrombectomy is performed under fluoroscopic guidance using a Fogarty balloon catheter. It is important to visualize the abdominal vena cava and all pelvic veins in the fluoroscopic field [15]. The common femoral vein, femoral vein, saphenofemoral junction, and the profunda femoris vein are exposed through a longitudinal inguinal incision. A longitudinal venotomy is then performed in the common femoral vein. Evacuation of infrainguinal venous thrombus requires leg elevation, bandage compression, and then manual compression of the calf and thigh [15]. If still present, a direct infrainguinal thrombectomy is performed by cutdown of the distal posterior tibial vein (Figure 15) [15]. A small Fogarty catheter is inserted into the distal posterior tibial vein and advanced to the common femoral venotomy. A silastic stem of an intravenous catheter is placed on this catheter and then another small Fogarty catheter is inserted on the opposite side of the silastic sheath. The second Fogarty balloon catheter is then guided distally to the posterior tibial venotomy. Then the infrainguinal venous thrombectomy is performed with multiple passes as needed [15].

Figure 15.

Open venous thrombectomy. (a and E) common femoral venotomy. (B) Fogarty balloon catheter guided to the posterior tibial venotomy prior to clot evacuation. (C and D) posterior tibial venotomy. Adapted from “Acute Lower Extremity Deep Venous Thrombosis: Surgical and Interventional Treatment,” by a.J. Comerota, and F. Aziz, 2022, Rutherford’s vascular surgery and endovascular therapy, p 1978. Copyright 2023 by Elsevier [15].

Once infrainguinal thrombectomy is completed, the infrainguinal veins are flushed with heparin-saline solution, and the femoral venotomy is clamped inferiorly. Dilute plasminogen activator solution is inserted into the infrainguinal venous system for the entire remainder of the procedure, allowing for breakdown of any residual infrainguinal thrombus [15].

Then treatment of the iliofemoral venous system begins under fluoroscopic guidance. A larger Fogarty balloon catheter is inserted into the iliac vein with multiple passes as needed. The catheter is then advanced into the inferior vena cava. If caval thrombus is present, a protective balloon catheter above the clot or an inferior vena cava filter can be deployed prior to caval thrombectomy. Completion venogram and intravascular ultrasound may be performed to assess for patency of drainage and anatomic iliac vein stenosis such as May-Thurner syndrome. Treatment of May-Thurner is as discussed earlier in the chapter. Once adequate thrombectomy has been performed, the femoral venotomy is closed and an arteriovenous (AV) fistula is created between the saphenous vein and the superficial femoral artery to increase venous velocity [15]. The fistula may lead to high-output cardiac failure, and if a patient experiences these symptoms, the fistula must be ligated [15]. The distal posterior tibial vein is then ligated. For those who had a posterior tibial venotomy performed, a small infusion catheter is inserted in the vein to maximize postoperative anticoagulation with heparin. A venogram may be performed prior to catheter removal to confirm venous patency. Post-operatively, the patient is transitioned to oral anticoagulation and routine post-operative care is performed as described later in the chapter [15].

10.2 Bypass of iliofemoral venous obstruction

The ideal venous bypass candidate has a unilateral occlusion of the iliofemoral vein with minimal thrombus and satisfactory valvular competence in the distal lower extremity [45]. Autogenous grafts, such as the great saphenous vein (GSV), are preferred due to low thrombogenicity. Other conduits include the contralateral femoral vein, jugular veins, and upper extremity veins. If an autogenous graft cannot be used, then expanded polytetrafluoroethylene (ePTFE) is the next best choice [45].

Due to low pressure venous flow, graft patency is lower than when used in the arterial system. Venous grafts have a higher chance of thrombosis due to graft collapse under increased pressure. As a solution, a distal AV fistula may be created to increase graft patency by increasing flow and decreasing platelet and fibrin deposition in the graft [45]. The anastomosis is typically performed between the superficial femoral artery and the distal part of the bypass graft [46]. With autogenous grafts, oral anticoagulation is continued for at least 3 months. If prosthetic graft is used, oral anticoagulation should be continued indefinitely [45].

10.3 Palma procedure (cross-pubic venous bypass)

The Palma procedure can be performed in symptomatic patients with unilateral chronic iliofemoral vein obstruction. This procedure involves a femoral vein to femoral vein bypass [47]. Contralateral GSV of at least 4 mm in diameter is the optimal conduit for this procedure. A 20–30 cm segment is typically harvested and flushed with heparinized papaverine solution to allow for distention. The GSV conduit is tunneled subcutaneously and suprapubic to the contralateral femoral vein. In order to expose the femoral vein on the affected side, a longitudinal groin incision is made. A femoral venotomy is performed and then an end-to-side anastomosis is created between the GSV conduit and femoral vein with 5-0 or 6-0 prolene. Intraoperative venography is usually performed to confirm no stenosis or kinks are present [46]. Due to the low pressure in venous bypasses, morbidly obese patients are not ideal candidates because of external compression of the bypass by the large pannus. For these patients, ePTFE may be considered [46].

10.4 May-husni procedure

The May-Husni procedure is performed in patients with unilateral isolated femoral vein obstruction. A longitudinal incision is made in the affected limb at the distal thigh in order to expose the GSV and distal femoral vein or proximal popliteal vein. The ipsilateral GSV is left in-situ with the inferior end ligated and mobilized. Then an end-to-side anastomosis is made to the distal femoral vein or proximal popliteal vein using a 6-0 prolene. Outflow is now rerouted through the GSV and bypasses the femoral vein obstruction [46].

11. Post-operative care

After endovascular and surgical treatment of iliofemoral DVT’s, compression dressings are applied and encouraged for use daily. Compression stockings may reduce the risk of developing PTS. Patients are transitioned to oral anticoagulation according to the durations as previously described in the chapter. Other recommendations after intervention include elevating the affected limb and early ambulation [48].

Post-operative follow-up with surveillance duplex imaging should occur at 1, 3, and 6 months, and then yearly thereafter [33]. If an iliac vein stent was placed, such as for May-Thurner syndrome, clopidogrel is recommended for 3 months, followed by aspirin indefinitely [48]. Hematology follow up may be required for recurrent DVT or hypercoagulable disorders. Additionally, a thorough evaluation for untreated venous stenosis may need to be performed if the patient has recurrent or unprovoked DVT [33].

12. Post-operative complications

The surgical treatment of DVT have complications for both open and endovascular interventions. Patients have risk of post-operative bleeding especially if pharmaceutical agents such as tPA are used, which may lead to hemorrhagic stroke. Acute kidney injury may occur with fluoroscopic use of contrast or hemolysis in rheolytic thrombectomy, and therefore caution is advised for chronic kidney disease patients. Additionally, there is the small risk of clot propagating to the lung and causing pulmonary embolism during or after thrombectomy procedures [33]. Complications of stent or bypass interventions include occlusion or stenosis of the stent or bypass. Additionally, if an ePTFE graft is used as a bypass conduit, there is a higher risk of infection. Compliance to anticoagulation and antiplatelet medications is imperative to ensure venous patency and to prevent recurrent DVT.

13. Conclusion

Acute iliofemoral DVT obstructs the single vessel outflow of the lower extremity. This may have devastating consequences if phlegmasia cerulea dolens or venous gangrene occur and requires immediate intervention. In less emergent scenarios where patients have persistent moderate to severe leg swelling and pain which is not improved on anticoagulation, surgical treatment is recommended to prevent post-thrombotic syndrome. Surgery can prevent symptoms of chronic venous insufficiency and has been shown to improve quality of life. Patient selection is important to increase surgical success. In patients with good functional status, life expectancy greater than 1 year, and low bleeding risk, surgery within 14 days of symptoms is recommended. Endovascular thrombolysis and/or thrombectomy has high success rates and is the initial surgical management of choice. Consideration of factors such as bleeding risk, renal function, body habitus, DVT chronicity, and sheath size is important in determining choice of endovascular device. Additionally, open venous thrombectomy and vein bypass may be performed if percutaneous techniques fail. Evaluation of underlying causes of venous stenosis and compliance with anticoagulation is important to prevent DVT recurrence.