Justin Hurie
Thomas W. Wakefield
Presentation
A 35-year-old man presents to the emergency department with a few days of left leg swelling and pain. The patient first noticed the swelling 3 days ago after returning on a long car trip from Florida. The patient describes his pain as an ache in his left leg and he has no prior episodes. The patient is otherwise healthy except that he smokes a half a pack of cigarettes a day. The patient takes no medications and has no family history of clotting and/or hypercoagulable conditions. The patient’s physical examination is essentially normal other than extensive asymmetric left leg swelling that does not involve the foot. The patient’s neurovascular examination is unremarkable, although pulses are only dopplerable and not palpable due to swelling.
Differential Diagnosis
In this scenario, the most likely diagnosis is deep venous thrombosis (DVT), which also carries the highest risk associated with a delay in diagnosis, given its association with pulmonary embolism. In an extreme form, phlegmesia cerulea dolens involves extensive DVT causing massive lower-extremity swelling and leg threat (see Figure 1). The patient is relatively young without a history of trauma or use of anticoagulation, which if positive could indicate a hematoma as an underlying etiology. Another cause of leg swelling is lymphedema, which tends to include swelling on the dorsum of the foot. Although it may arise spontaneously, lymphedema may also be iatrogenic, after surgery or radiation therapy. Other possible causes of leg swelling include congestive heart failure or nephrotic syndrome, but these generally involve bilateral leg swelling.
FIGURE 1 • Photograph of a patient with phlegmesia cerulea dolens.
Workup
Venous thromboembolism (VTE) is a common diagnosis encompassing deep vein thrombosis and pulmonary embolism, with a yearly incidence >900,000 in some estimates. The most widely utilized test to diagnose DVT is duplex ultrasound imaging with a sensitivity and specificity >95%. First, an ultrasound is performed using gray scale to image the external iliac, femoral, and popliteal veins. The veins below the knee are able to be imaged although with less reliability. Under direct vision, compression is applied, which causes normal veins to collapse completely indicating patency (see Figure 2). When veins fail to collapse, either partially or completely, this indicates intraluminal material, usually either acute thrombus or chronic scar tissue (see Figure 3). There are rough guidelines to distinguish acute from chronic clot, but none are definitive or absolute (see Table 1). Acute clot generally appears echolucent and the vein that contains the clot may appear enlarged on ultrasound. As DVT becomes chronic, its ultrasound appearance changes and becomes echodense and heterogeneous, and the vein shrinks in size. Subacute thrombus generally represents a noncompressible vein with a combination of features of both acute and chronic clot.
FIGURE 2 • Ultrasound demonstrating complete collapse with compression indicating a patent femoral vein.
FIGURE 3 • Ultrasound demonstrating only partial collapse with compression indicating intraluminal thrombus.
TABLE 1. Acute Versus Chronic DVT
The second component of duplex evaluation involves using color flow doppler. Color flow may give additional information regarding partial versus complete occlusion. In addition, color flow may give indirect evidence of occlusions not directly visualized. Lack of respiratory variation indicates an obstruction cephalad to the vessel that is being imaged. Flow augmentation is used to evaluate patency of caudad vessels.
Diagnosis and Treatment
The leading diagnosis is DVT and the main modality of treatment is anticoagulation. Initially, the patient may be treated with intravenous unfractionated heparin, subcutaneous low-molecular-weight heparin (LMWH), or fondaparinux. Patients with a reversible cause of DVT may be then treated with 3 months of anticoagulation using a vitamin K antagonist. An exception is patients with an active diagnosis of cancer who should be treated with 3 months of LMWH. In patients with an unprovoked DVT, the duration of treatment depends on the patient’s underlying coagulability and should be at least 3 months. More details regarding duration of treatment are found in the CHEST guidelines (see suggested readings). Newer treatment modalities include the use of thrombolysis with the goal of reduction of clot burden. The goal of thrombolysis is to decrease the chance of developing one of the long-term sequelae of DVT, chronic venous insufficiency. Chronic venous insufficiency is due to longstanding venous hypertension, either due to valvular incompetence, obstruction or both. It occurs in up to 30% to 40% of patients 5 years after developing a DVT, with an even higher incidence in those with iliofemoral DVT and those with ipsilateral recurrent DVT. Risk factors for chronic venous insufficiency include multiple DVTs, advanced age, cancer, recent surgery, immobilization or trauma, pregnancy, hormone replacement therapy, obesity, and gender.
In younger patients without a clear etiology, it is important to look for anatomic risk factors, such as the May-Thurner syndrome, defined as compression of the left iliac vein by the overlying right iliac artery, which forms an area of narrowing predisposing to thrombosis. Treatment of the May-Thurner syndrome includes venoplasty and stenting and, if thrombosis, thrombolysis, venoplasty, and stenting (see Figure 4).
FIGURE 4 • Depiction and treatment of May-Thurner syndrome, which is left iliac vein compression by the overlying right iliac artery.
Surgical Approach
The primary determinant of the level of intervention is guided by the degree of symptoms. Systemic anticoagulation is the primary treatment for DVT. In patients that are unable to be anticoagulated, DVT is an indication for placement of an inferior vena cava filter. In patients with severe symptoms of leg swelling and extensive DVT, more aggressive intervention is indicated. In the most severe form, patients with phlegmesia cerulea dolens require venous decompression in order to decrease the chance of venous gangrene and the associated 20% to 50% amputation rate. One modality involves catheter-directed thrombolysis, which more quickly restores patency compared to anticoagulation alone. In patients that fail to respond to thombolysis, open venous thrombectomy remains a good option. There are a variety of adjunctive measures that may be required in order to correct any underlying anatomic abnormality. In severe cases with limb threat, fasciotomy after or simultaneous with thrombolysis or thrombectomy may be required to avoid amputation.
The patient should be placed on full anticoagulation involving heparin including a bolus (80 U/kg) or LMWH (1 mg/kg). Thrombolysis involves prepping the bilateral lower extremities circumferentially. The venous system may be accessed in the groin or peripherally at the popliteal area. Once a guidewire is passed across the lesion and position confirmed within the distal vein, an infusion catheter may be placed with an infusion run overnight. Along with pharmacologic thrombolysis, today mechanical catheters are also used. These catheters use various physical principles to help obliterate thrombus, and when used in combination may decrease both the amount of thrombolysis needed and also the time thrombolysis is required (pharmacomechanical thrombolysis).
If these methods fail to reestablish outflow, open surgery may be indicated. The femoral vein is exposed through a groin incision. Cephalad and caudad control is obtained with vessel loops and a venotomy is made through the vein itself or a sidebranch. Five or six French venous thrombectomy catheters may be carefully passed in order to remove thrombus and reestablish venous flow. In patients with a chronic DVT, the femoral vein often contains webs (scar tissue) that requires removal. Once adequate flow is established, the venotomy may be closed with a polypropylene suture or with a patch of vein or polyester. A completion duplex is performed in order to evaluate for technical problems. In some patients, an additional venogram may be needed in order to confirm adequate clearance of clot.
Given the required use of postoperative anticoagulation, there is a significant risk of bleeding. This requires careful postoperative observation and adequate drainage. Another potential pitfall involves the unforgiving nature of venous interventions and a low-flow state. This requires the use of intraoperative duplex in order to evaluate for technical errors that may be easily remedied at the time of the initial procedure but may be catastrophic at a later point (Table 2).
TABLE 2. Key Technical Steps and Potential Pitfalls in Thrombectomy/Thrombolysis
HIT, heparin-induced thrombocytopenia; DIC, disseminated intravascular coagulation
Special Intraoperative Considerations
As with most vascular cases, potential difficult situations will usually involve bleeding or the lack thereof. In terms of postoperative bleeding, one potential source is technical or another is generalized oozing due to ongoing anticoagulation. Additional causes of bleeding include the development of heparin-induced thrombocytopenia (HIT) or disseminated intravascular coagulation (DIC). HIT usually manifests 3 to 10 days after administration of heparin, although the time can be reduced with prior exposure. DIC can complicate thrombolysis and requires the serial measurement of fibrinogen levels. Finally, lack of flow can be just as detrimental predisposing the patient to vein and stent thrombosis. Outflow into pelvic veins can usually be treated using a combination of stenting and venoplasty. A more troubling problem can be lack of adequate inflow. Adjunctive measures can include additional stent placement across the inguinal ligament or creation of an arteriovenous fistula in order to augment inflow (see Figure 4).
Postoperative Management
The use of elevation, compression, and ambulation can reduce the incidence of chronic venous insufficiency (postthrombotic syndrome) by 50% and should be recommended to all patients with DVT along with adequate anticoagulation. In the case presented, the patient underwent thrombolysis and stenting for May-Thurner syndrome. The patient had resolution of her symptoms and improvement in her leg swelling. Postoperatively, the patient was treated with anticoagulation for 3 months and continues to wear compression stockings.
TAKE HOME POINTS
· VTE is common with an incidence of more than 900,000 cases per year.
· Duplex evaluation is the cornerstone for diagnosis of DVT.
· Evaluate for phlegmesia given the high rate of associated gangrene and amputation.
· Anticoagulation is a cornerstone for the treatment of DVT and duration of therapy depends on etiology.
· Consider thrombolysis for significant symptoms or limb threat in order to reduce thrombus burden.
· Excessive bleeding may be due to a technical problems but may also occur with HIT or DIC.
· May-Thurner syndrome is a common etiology of left lower-extremity swelling in patients without other risk factors for disease.
· Chronic venous insufficiency is a challenging problem with a range of symptoms from pain and swelling to nonhealing ulcers. The use of adjunctive measures, such as compression, elevation, and ambulation, may reduce the incidence by 50%.
SUGGESTED READINGS
Cronenwett JL, Johnston W. Rutherford’s Vascular Surgery. 7th ed. Philadelphia, PA: Saunders, 2010.
Gloviczki P. Handbook of Venous Disorders. Guidelines of the American Venous Forum. 3rd ed. Oxford, UK: Oxford University Press, 2009.
Kearon C, Kahn SR, Agnelli G, et al. Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th ed). Chest. 2008;133(6 suppl):454S–545S.
Wakefield TW, Caprini J, Comerota AJ. Thromboembolic disease. Curr Probl Surg. 2008;45(12):833–900.
Wakefield TW. Venous thrombosis. In: Bope ET, Kellerman RD, Rakel RD eds. Conn’s Current Therapy. Philadelphia, PA: Elsevier, 2011.
Zwiebel WJ, Pellerito J. Introduction toVascular Ultrasonography. 5th ed. Philadelphia, PA: Saunders, 2005.