Subclavian Vein Thrombosis Treatment & Management

In patients with effort-induced vein thrombosis of less than 2 weeks' duration, thrombolytic therapy is recommended. Chronic axillary-subclavian vein thrombosis (ASVT) rarely responds to thrombolytics and generally is better treated either conservatively with warfarin or, if symptoms are severe, with surgical bypass. A systematic review by Keir et al found first-rib resection followed by long-term anticoagulation to be the best treatment approach for chronic subclavian vein thrombosis. ^[11]

Surgery is rarely indicated for ASVT associated with central lines. 

Initial treatment of subclavian vein thrombosis consists of conservative management, which includes rest, elevation of the limb, and application of heat or warm compresses.

In a few patients who have minimal symptoms and no anatomic defects, physical therapy is the first component of treatment. Structured physical therapy may help the patient lose weight and loosens the adhesions at the site of obstruction. Physical therapy may also improve range of motion (ROM), decrease swelling, and help decrease pain.

The different natural histories of Paget–von Schrötter syndrome and catheter-induced subclavian vein thrombosis indicate different treatment protocols. Because large series of patients with this condition are lacking, the therapeutic approach to subclavian vein thrombosis is mainly anecdotal.

Anticoagulation

Unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) can maintain the patency of the venous collaterals and reduce the chance of propagation of the thrombus. In all cases, heparin therapy is followed by warfarin therapy, with a target international normalized ratio (INR) of 2-3.

Heparin is usually the initial therapy, followed by warfarin. LMWH has been used for both inpatient and outpatient therapy. Most studies have shown that LMWH is just as effective as UFH, but the former is associated with a significantly decreased incidence of venous thromboembolism.

Warfarin is continued for 6-9 months, and an INR of 2-3 is maintained. Patients who only receive inpatient heparin and are no longer on warfarin therapy are at risk for recurrence and long-term disability. Anticoagulation is required in all patients for a period of 6-9 months or longer, depending on the cause of the thoracic outlet syndrome. In some patients who also have hypercoagulable disorders, treatment is lifelong.

Levy et al, in a study involving 300 patients with upper-extremity deep vein thrombosis (DVT; including 161 with subclavian obstruction and 107 with axillary obstruction), concluded that in view of the low (2%) incidence of pulmonary embolism (PE) attributable to upper-extremity DVT, regardless of anticoagulant therapy, analysis of risks vs benefits does not favor routine anticoagulation in this setting. ^[12]

Paget–von Schrötter syndrome

Currently, most investigators favor using thrombolytic therapy to rapidly restore the patency of the vein. Thrombolytic therapy should be initiated within 5-7 days of venous thrombosis. Fortunately, this syndrome occurs in fairly young individuals who do not have multiple medical illnesses that may contraindicate thrombolytic therapy. Thrombolytic therapy is preferred to thrombectomy because it does not carry the risks of an operation and the possibility of an intimal tear related to the embolectomy catheter.

In some cases, therapy may involve diagnostic venography, followed by thrombolysis, followed by several weeks of anticoagulation. If symptoms recur, a repeat venography may be indicated, possibly followed by balloon dilatation with or without stenting of the subclavian vein, and more anticoagulation. (See the image below.) The desired INR is 2-3. The goal of therapy is to minimize the likelihood of significant symptoms of venous obstruction.

To perform catheter-directed thrombolysis, the catheter is embedded in the thrombus. Urokinase infusion is started with a loading dose of 250,000 IU, followed by 4000 IU for the first hour, and 1000 IU for the next 24 hours. Heparin is infused at a rate of 800 IU/hr. Monitoring is performed by maintaining a fibrinogen level of at least 80-100 mg/dL. If venous patency is assured, warfarin is maintained for 3-6 months.

The removal of urokinase from the US market forced interventional radiologists to adopt less clinically defined protocols using tissue plasminogen activator (tPA). As the clinical situation with thrombolytic agents evolves and other agents enter the market, flexibility in thrombolytic administration protocols will be paramount.

Catheter-associated subclavian vein thrombosis

Prophylaxis in patients undergoing chemotherapy may include giving a fixed 1-mg dose of warfarin sodium daily, beginning on day 3 before catheter placement. This has been shown to lower the incidence of thrombosis. Exercise caution in selecting patients for thrombolytic therapy because patients with catheter-associated subclavian thrombosis often have significant comorbidity.

Indications for surgical treatment include the following:

• Presence of an anatomic anomaly, such as an anomalous subclavius or scalenus anterior, congenital fibromuscular bands, or narrowing of the costoclavicular space from depression of the shoulder
• Rethrombosis of the vein after previous thrombolytic treatment
• Endoluminal stent placement to prevent stent fracture from compression against the first rib

Possible forms of surgical treatment include the following:

• Embolectomy
• Bypass
• First-rib resection via a transaxillary or supraclavicular approach
• Medial subtotal claviculectomy

Conventional approach

Preoperative evaluation

The purpose of the preoperative evaluation is to determine whether there is any known or unsuspected coexisting disease that should delay, modify, or preclude the operation. Obtain a history and physical examination to identify risk factors and warning signs of coexisting diseases. This information guides further direction and depth of study. Relevant laboratory tests include the following:

• Complete blood count (CBC)
• Serum electrolyte levels
• Urinalysis
• Chest radiography
• Electrocardiography (ECG)
• Clotting profile
• Crossmatch
• Stool examination for blood.

Consultations should include a general internal medicine physician and an anesthesiologist.

Procedure

A first-rib resection may be carried out via either the transaxillary route ^[13] or the supraclavicular route (though it has been suggested that an infraclavicular approach may have benefits ^[14] ). Typically, the transaxillary route is simpler and safer and offers cosmetic benefits. The procedure is described below.

The patient is placed in the lateral thoracotomy position with the arm elevated. A skin incision is made in the axillary hairline between the pectoralis major and the latissimus dorsi. The first rib is reached by blunt dissection in the axillary tunnel, with care taken to avoid the second intercostobrachial nerve.

The subclavian artery and vein are identified, and the subclavius tendon is divided. Then, the scalenus anterior is identified and divided at the point where it inserts onto the first rib, anterior to the artery.

At this point, a digital search is made for anomalous bands. They may originate from the C7 transverse process, from an incomplete cervical rib, or from the scalenus medius.

After any bands are divided, the scalenus medius and the intercostal muscle attachments are pushed off the first rib. When all the muscle fibers are cleared and the T1 nerve root is visualized and protected, the rib is divided and removed.

The wound is irrigated with saline to detect pneumothorax. If pneumothorax is present, it can be treated by inserting a small chest tube into the pleural space. The tube can be removed in the recovery room if the lung is fully expanded and no air leak is present.

Postoperative care

Pain relief is one of the most important aspects of postoperative care. Various forms of narcotics can be administered parenterally or by patient-controlled analgesia devices. The importance of adequate pain control cannot be overemphasized.

Vital signs should be closely monitored as per unit protocol, then every 4 hours for 24 hours, and then every shift. In most cases, a Foley catheter is not required. Administer 5% dextrose in lactated Ringer solution at a rate of 125 mL/hr, and keep the arm elevated.

If the operation is not complicated, routine postoperative laboratory tests are not required. The prothrombin time (PT) and activated partial thromboplastin time (aPTT) should be measured every 6 hours if heparin therapy is started.

Early mobilization is important, and discharge planning should begin at admission. Patients usually are discharged when they are medically stable, afebrile, tolerant of oral intake, ambulatory, and reasonably comfortable with the ongoing rehabilitation exercises.

Endovascular treatment

Angioplasty with stenting is an excellent way to maintain venous patency; though data and follow-up on this technique are limited. When the superior vena cava is also involved, current endovascular techniques allow for stenting of the vessel, which produces excellent results.

Suction thrombectomy with an AngioJet System (Possis Medical, Minneapolis, MN) is often used with thrombolysis when the thrombus is localized. The procedure can rapidly extract the thrombus and reduce both the dose and duration of thrombolytic therapy. Suction thrombectomy is most useful for patients who present early. Surgical thrombectomy is fast becoming the procedure of choice; it is a better alternative to simple anticoagulation.

Pharmacomechanical thrombectomy appears to be effective for early thrombus removal in patients with Paget–von Schrötter syndrome; subsequent thoracoscopic or open surgical decompression of the subclavian vein should be considered. ^[15]

Complications related to surgery include the following:

• Injury to the phrenic nerve
• Chronic pain
• Pneumothorax
• Arm swelling due to excessive dissection in the axilla
• Recurrence of symptoms
• Incomplete resection of the first rib

After surgery, it is important to have the patient enrolled in a physical therapy program. There is moderate pain after the procedure, which may take 5-10 days to subside. Physical therapy can help improve muscle function, enhance ROM of the arm, and prevent swelling of the ipsilateral arm.

Patients with subclavian vein thrombosis must be followed carefully to ensure that the condition does not recur. Patients with persistent symptoms and evidence of recurrence may require radiologic workup and, possibly, surgery.