416507JDMXXX10.1177/8756479311416507Wash ko et al.journal of Diagnostic Medical Sonography Pseudothrombosis of the Subclavian Vein Journal of Diagnostic Medical Sonography 27(5) 231 235 The Author(s) 2011 Reprints and permission: http://www. sagepub.com/journalspermissions.nav DOI: 10.1177/8756479311416507 http://jdm.sagepub.com Patrick A. Washko, BSRT, RDMS, RVT 1, S. Wayne Smith, MD, RVT, RDMS 1, Savannah Reese, RDMS, RVT 1, Brian Stull, RDMS, RVT 1, and Susan Rimmer, RDCS, RDMS, RVS 1 Abstract A woman in her late 20s presented one week after an abdominoplasty surgical procedure to the emergency room complaining of shortness of breath and chest pain. A chest computed tomography angiogram (CTA) pulmonary embolism protocol (PE) was ordered to rule out acute PE. The CTA study was negative for PE, but an incidental finding of complete obstruction of the right subclavian vein was noted. Keywords thoracic outlet syndrome (TOS), costoclavicular ligament, hyperabduction maneuvers, Paget-Schroetter Case History A woman in her late 20s presented one week after an abdominoplasty surgical procedure to the emergency room complaining of shortness of breath and chest pain. Her past medical history included anxiety disorder, headaches, right upper extremity numbness, and tingling. This extremity developed a sensation of fullness when performing exertion activities. Family history was negative for thromboembolic disease, and the patient denied the use of birth control pills. Prescription medications included Cymbalta and Toradol. Vital signs included a heart rate of 122 beats per minute, respiratory rate of 22 per minute, and normal blood pressure. The cardiopulmonary examination was negative. Pulse oximetry (O 2 saturation) was 96%, and edema was not visualized in the upper or lower extremities. Comprehensive blood count was within normal limits, and the D-dimer results were elevated at 0.87 ng/ml (normal range, 0 0.50 ng/ml of blood). A chest computed tomography angiogram (CTA) was negative for acute pulmonary embolism. Occlusion of the right subclavian vein was visualized with extensive collaterals reconstituting the right external jugular and superior vena cava (Figures 1 and 2). On the basis of the abnormal CTA findings, the patient was referred to the vascular laboratory for vascular medicine consultation and an upper extremity venous duplex sonogram to evaluate the presence of deep venous thrombosis. The venous duplex sonographic evaluation was unremarkable with no evidence of superficial or deep Figure 1. Occlusion of the right subclavian vein visualized with extensive collaterals reconstituting the right external jugular and superior vena cava. Pulmonary CTA hyperabduction maneuver (RUE). vein thrombosis. Doppler flow patterns were symmetrical (Figures 3 and 4). The venous duplex sonographic examination was repeated mimicking the upper extremity positioning used during the CTA (right upper arm extension above the head with shoulder abduction; Figure 5). The change in right upper extremity position demonstrated dilation of the axillary vein, with slow 1 Rex Hospital, Raleigh, NC, USA Corresponding Author: Patrick A. Washko, BSRT, RDMS, RVT, Rex Hospital, 4420 Lake Boone Trail, Raleigh, NC 27607, USA Email: Patrick.Washko@Rexhealth.com
232 Figure 2. Occlusion of the right subclavian vein visualized with extensive collaterals reconstituting the right external jugular and superior vena cava. Pulmonary CTA hyperabduction maneuver (RUE). Journal of Diagnostic Medical Sonography 27(5) Figure 5. Venous duplex sonographic examination mimicking the upper extremity positioning used during the computed tomography angiogram (right upper arm extension above the head with shoulder abduction). Figure 6. Raised extremity position demonstrated by dilation of the axillary vein, with slow stagnant rouleaux flow, and complete cessation of venous pulsatility on duplex sonography. Figure 3. Neutral arm position of a venous duplex sonographic evaluation with no evidence of superficial or deep vein thrombosis. Doppler flow patterns were symmetrical. stagnant rouleaux flow, and complete cessation of venous pulsatility on duplex sonography. These findings are consistent with subclavian vein compression and venous-type thoracic outlet syndrome (TOS; Figure 6). The sonographic findings were confirmed with upper extremity positional venography. Upon hyperextension and upper extremity elevation maneuvers, the right axillary and subclavian venous flow transitioned from normal to high-grade subclavian obstruction at the clavicle first rib region. Note the presence of collaterals upon hyperextension (Figures 7 and 8). Discussion Figure 4. Normal color flow of a venous duplex sonographic evaluation with no evidence of superficial or deep vein thrombosis. Doppler flow patterns were symmetrical. TOS may involve compression of the neurovascular bundle at the superior thoracic outlet. Different symptoms and physical findings describe each of the three types of TOS.1 Compression involving the components of the brachial plexus nerves is termed neurogenic TOS and accounts for 95% of described cases of TOS. Arterial TOS, first described by Sir Ashley Cooper in 1821, identifies axillarysubclavian artery symptoms due to compression involving
Washko et al. 233 Figure 7. Venography of neutral arm position. Figure 8. Venography of hyperextension arm position. Note the presence of collaterals upon hyperextension. a cervical rib. In 1875, James Paget described the symptoms of subclavian vein thrombosis, and in 1884, von Schroetter attributed these upper extremity symptoms to subclavian vein thrombosis or compression of the subclavian vein at the thoracic outlet. Venous TOS (with secondary venous thrombosis) secondary to extrinsic compression via impingement of the subclavian vein is more commonly known as Paget-Schroeder syndrome. 1 Description of the type of TOS, whether venous, arterial, or neurogenic, provides important clinical information to the providers caring for the patient. TOS is often misdiagnosed because of the variable clinical presentations (i.e., neurogenic, arterial, or venous compression). Neurogenic TOS is most frequent, whereas venous TOS is least often seen and is dominant in males by a 2:1 ratio. Neurogenic and arterial TOS are most often the result of compression at the scalene triangle. Venous TOS results most often from compression of the subclavian vein in the costoclavicular space by the subclavius muscle tendon and the costoclavicular ligament (see Figure 9). Venous TOS occurs most often in the dominant upper extremity. A standard venous sonography protocol should be followed that includes B-mode, color Doppler, and spectral Doppler evaluation. Multiple acoustic windows (supraclavicular and infraclavicular) and patient positions may be necessary for imaging each section of the upper extremity. 2 The upper extremity venous sonogram is best performed in the supine position, but many clinical situations may not allow this positioning. Optimal results may be seen without head elevation because hydrostatic pressure changes may collapse the internal jugular, subclavian, and axillary veins. Venous flow dynamics differ in the upper and lower extremities. Normal lower extremity venous sonography demonstrates spontaneous and phasic flow, whereas upper extremity venous flow dynamics are pulsatile due to the proximity of the heart. When performing venous sonography of a unilateral upper extremity, examination of the contralateral subclavian and axillary vein is recommended to exclude the presence of a central obstruction. See Doppler spectral images in Figures 10 and 11 of normal left and right subclavian veins. The presentation for venous TOS includes pain, swelling, and/or cyanosis of extremity, usually following strenuous physical activity. 3 Signs of arterial or neurogenic TOS include numbness or tingling of the arm, pain or aching of the shoulder and forearm, and an increase in discomfort and symptoms with exercise or upward positioning of the extremity. In the presence of a normal venous sonographic examination and clinical symptoms that appear to be positional, the technologist should evaluate the effect on venous flow with shoulder abduction, external rotation, and raising the affected extremity (TOS maneuvers). The patient in this case study has done well with conservative treatment. Physical therapy for postural exercises and stretching has been of benefit, as well as avoidance of shoulder movement that obstructs the subclavian vein. She has been advised to avoid estrogen treatment and is not on anticoagulation medications. A thrombophilic workup was unremarkable. A nine-month follow-up venous sonographic evaluation demonstrated normal findings in the neutral position with persistent impeded subclavian flow during hyperabduction of the shoulder and raising the right upper extremity.
234 Journal of Diagnostic Medical Sonography 27(5) Figure 9. Venous thoracic outlet syndrome. Medical illustration by Dawn Washko, RHIA. Figure 10. Doppler spectral images of normal right subclavian vein. Figure 11. Doppler spectral images of normal left subclavian vein. Conclusion Unilateral upper extremity swelling is a common indication for venous sonographic studies. Unless there is a history of trauma, the differential diagnosis is typically lymphedema versus deep venous thrombosis. Most upper extremity deep vein thrombosis is related to catheter interventions, chemotherapy (portacaths), peripherally inserted central catheter (PICC or PIC) lines, and pacemaker/defibrillator lead wires. Paget-Schroetter syndrome is an effort-induced thrombosis secondary to impingement of the subclavian vein by the costoclavicular ligament or subclavius muscle tendon and typically occurs in the dominant extremity. This patient represents positional subclavian vein obstruction without thrombus detected by a chest CTA done
Washko et al. 235 for pulmonary embolism. In patients with episodic unilateral swelling, it is recommended that the venous duplex examination be performed in the neutral position and then with the shoulder abducted and extremity elevated. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the authorship and/or publication of this article. Funding The author(s) received no financial support for the research and/or authorship of this article. References 1. Eskandari MK: Thoracic outlet obstruction. November 2, 2009. http://emedicine.medscape.com/article/462166-overview. Accessed March 15, 2011. 2. Society of Vascular Ultrasound: SVU Upper Extremity Venous Duplex Evaluation R/O Superficial Vein Thrombosis: Vascular Technology Professional Performance Guidelines. Lanham, MD, Society of Vascular Ultrasound, 2010. 3. Zwiebel W: Introduction to Vascular Ultrasonography. 3rd ed. Philadelphia, W. B. Saunders, 1992.