para>Older patients are more likely to have arteriosclerosis. ‚
DIAGNOSIS
- Reduced BP of >20 mm Hg in involved arm
- Symptoms should be reproducible by exercising the arm.
- A variation of the syndrome is the coronary " “subclavian steal syndrome, which can only occur after coronary artery bypass grafting (CABG), using the internal mammary artery (IMA); may present with symptoms of cardiac ischemia.
- The IMA is attached usually to the LAD; if patient develops subclavian artery stenosis proximal to the take-off of the IMA, patient has potential for having coronary steal syndrome (1)[B].
- EKG typically shows ST elevations in aVR with reciprocal depressions in lateral leads (1)[B].
HISTORY
- Patients can present with:
- Upper extremity claudication or muscle fatigue following minimal exercise, rest pain, ulcers, and digital necrosis
- Transient ischemic attacks (usually of the vertebrobasilar territory) often precipitated by exercise or work of the involved upper extremity.
- Symptoms of vertebrobasilar ischemia include dizziness, vertigo, diplopia, dysarthria, dysphagia, ataxia, gait disturbances, numbness, nystagmus, syncope, hearing loss, and tinnitus.
- Classified as asymptomatic, oligosymptomatic (only neurologic symptoms or upper limb ischemia is present), or complete (both symptoms)
PHYSICAL EXAM
- Absent, diminished, or delayed pulses in ipsilateral arm:
- Compare carotid, subclavian, brachial, radial, and ulnar pulses.
- Using a handheld continuous wave Doppler, a monophasic or reduced biphasic pulse may be heard distal to the lesion.
- A brachial systolic pressure difference of >15 mm Hg is >90% specific for subclavian stenosis (only ~50% sensitive).
- Auscultation of carotid and suprascapular bruits
- Physical examination can subdivide subclavian stenosis as moderate (difference >15 and <25 mm Hg between the arms) or severe (difference >25 mm Hg). This correlates with long-term prognosis.
- Compression " “decompression test (hyperemia test): Inflate a BP cuff above the systolic BP for 3 minutes. Vertebrobasilar symptoms may be reproduced by rapid decompression.
- Evaluation of upper extremities for evidence of embolic disease such as splinter hemorrhages under the nail beds, blue fingers, livedo reticularis, and digital ischemia
- Perform Allen test bilaterally.
DIFFERENTIAL DIAGNOSIS
- Vascular: intracranial vascular disease, carotid artery disease, vertebral artery disease
- Takayasu arteritis, especially if there are multiple pulse deficits.
- Thoracic outlet obstruction particularly in athletes such as baseball pitchers and golfers
- Neurogenic: brain tumor, seizures, subdural hematoma
- Cardiac arrhythmias
DIAGNOSTIC TESTS & INTERPRETATION
- No lab findings are pathognomonic for SSS.
- Noninvasive measurement of BP in upper extremities
- Pulse volume recording of upper extremities
- If Takayasu arteritis is suspected:
- Erythrocyte sedimentation rate (ESR) (elevated)
- CBC (thrombocytosis)
- ECG (ischemic pattern)
- Chest x-ray (CXR) (widening of thoracic aorta)
- Duplex ultrasound with color flow: noninvasive modality of choice
- Magnetic resonance angiography (MRA) or computed tomography (CT) as confirmatory tests
- Arteriogram of arch vessels, with delayed films of vertebral arteries
Diagnostic Procedures/Other
- Contrast angiography
- Doppler ultrasound may be used as screening test.
- CT angiography
- MRA
- According to the hemodynamics, there are four subtypes:
- Vertebrovertebral
- Carotid " “basilar
- External carotid " “vertebral
- Carotid " “subclavian (can only occur on the right side with brachiocephalic occlusion proximal to the origin of the carotid artery)
TREATMENT
GENERAL MEASURES
- Antiplatelet therapy with aspirin (or clopidogrel, if intolerant of aspirin), especially in patients with concomitant coronary artery disease
- Reduce cholesterol levels, if appropriate, using diet or medication (statin drugs) with a goal of low-density lipoprotein (LDL) <100
- Cessation of smoking (2)[A]
ISSUES FOR REFERRAL
- In symptomatic patients, consult vascular medicine and cardiovascular surgery.
- Potential indications for subclavian artery intervention include:
- Vertebrobasilar ischemia
- Disabling upper limb ischemia: rest pain and digital embolization
- Angina in a patient with a left internal mammary artery (LIMA) graft
- Leg claudication in patient with axillofemoral graft
- To increase flow before CABG using the IMA or before creation of dialysis arteriovenous fistula
SURGERY/OTHER PROCEDURES
Treatment options include: ‚
- Balloon angioplasty: stent insertion increases long-term patency rates:
- The 8- to 10-year primary patency is 83 " “95% (3)[B]
- The 2- and 5-year patency rates with PTA was 100% and 85.7%, respectively (4)[B].
- Long-term patency can be aided with antiplatelet agents.
- Complications occur in up to 10% of the cases and include:
- Femoral pseudoaneurysm
- Embolic stroke (0.9 " “1.4% complication rate)
- Distal embolism
- AV fistula
- Stent restenosis
- The overall patency rates comparing bypass versus PTA appears to be statistically equivalent (5)[B].
- Carotid " “subclavian bypass (2)[A]
- Carotid-subclavian transposition:
- To be considered if there is distal embolization from the subclavian artery lesion
- The reported patency is 100% at 10 years compared with 74% for carotid bypass
- Axilloaxillary bypass: 12-year graft occlusion of 10% and 0.4% periprocedural mortality
- Carotid endarterectomy
- Subclavian arterectomy
- The majority of data regarding the surgical correction of SSS and coronary-subclavian steal syndrome are based on case studies and retrospective studies. There are currently no RCT studies.
INPATIENT CONSIDERATIONS
Aggressive management of cardiovascular risk factors ‚
Admission Criteria/Initial Stabilization
- Stroke, critical limb ischemia
- Outpatient care, unless vascular surgery is anticipated
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
- Poststenting follow-up at 1-, 6-, and 12-month intervals initially, then yearly thereafter
- Frequent neurologic review of systems and subclavian Doppler ultrasound for patients who become symptomatic or have a BP difference of >10 mm Hg between arms.
Patient Monitoring
Annual physical examination, including BP reading in both arms, in patients with known stenosis. Reducing atherosclerotic risks factors such as hypertension, diabetes mellitus, hyperlipidemia and smoking cessation. ‚
DIET
Low-cholesterol diet, if appropriate ‚
PATIENT EDUCATION
- Prevent injury to arm
- Reduce exercise of arm
PROGNOSIS
- The presence of subclavian stenosis recently has been defined as an independent risk factor for cardiovascular death.
- After angioplasty of the subclavian artery, younger age and stenting are independent predictors of restenosis-free survival.
COMPLICATIONS
Completed stroke ‚
REFERENCES
11 Potter ‚ BJ, Pinto ‚ DS. Subclavian steal syndrome. Circulation. 2014;129(22):2320 " “2323.22 Brott ‚ TG, Halperin ‚ JL, Abbara ‚ S, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. J Am Coll Cardiol. 2011;57(8):1002 " “1044.33 Higashimori ‚ A, Morioka ‚ N, Shiotani ‚ S, et al. Long-term results of primary stenting for subclavian artery disease. Catheter Cardiovasc Interv. 2013;82(5):696 " “700.44 Hwang ‚ HY, Kim ‚ JH, Lee ‚ W, et al. Left subclavian artery stenosis in coronary artery bypass: prevalence and revascularization strategies. Ann Thorac Surg. 2010;89(4):1146 " “1150.55 Wang ‚ KQ, Wang ‚ ZG, Yang ‚ BZ, et al. Long-term results of endovascular therapy for proximal subclavian arterial obstructive lesions. Chin Med J. 2010;123(1):45 " “50.
ADDITIONAL READING
- Aboyans ‚ V, Criqui ‚ MH, McDermott ‚ MM, et al. The vital prognosis of subclavian stenosis. J Am Coll Cardiol. 2007;49(14):1540 " “1545.
- Alcocer ‚ F, David ‚ M, Goodman ‚ R, et al. A forgotten vascular disease with important clinical implications. Subclavian steal syndrome. Am J Case Rep. 2013;14:58 " “62.
- Kotelis ‚ D, Geisb ƒ ¼sch ‚ P, Hinz ‚ U, et al. Short and midterm results after left subclavian artery coverage during endovascular repair of the thoracic aorta. J Vasc Surg. 2009;50(6):1285 " “1292.
- Sixt ‚ S, Rastan ‚ A, Schwarzw ƒ ¤lder ‚ U, et al. Long term outcome after balloon angioplasty and stenting of subclavian artery obstruction: a single centre experience. Vasa. 2008;37(2):174 " “182.
- Tsivgoulis ‚ G, Heliopoulos ‚ I, Vadikolias ‚ K, et al. Subclavian steal syndrome secondary to Takayasu arteritis in a young female Caucasian patient. J Neurol Sci. 2010;296(1 " “2):110 " “111.
CODES
ICD10
G45.8 Oth transient cerebral ischemic attacks and related synd ‚
ICD9
435.2 Subclavian steal syndrome ‚
SNOMED
Subclavian steal syndrome ‚
CLINICAL PEARLS
- Takayasu arteritis/vasculitis is most common in young females. The aorta and its branches are the major vessels affected by inflammation, thrombus formation, and aneurysmal dilatation. SSS is thought to be relatively common in this disorder.
- The left upper extremity is affected more frequently, perhaps because subclavian steal occurs when the obstruction is proximal to the origin of the vertebral artery, and this distance is shorter on the right than on the left.
- The physical findings associated with SSS are lower BP, decreased pulse, and bruit (supraclavicular) on the affected side.
- Possible presence of subclavian artery stenosis should be assessed before bypass surgery when a LIMA graft is planned. If present, a stenosis may present later on as coronary " “subclavian steal syndrome.