Vertebral and Subclavian Disease

Vertebral-Subclavian Atherosclerosis

Atherosclerosis is the most common cause of vertebral and subclavian artery disease, typically affecting the ostium of the vertebral artery and the proximal subclavian artery.

Non-atherosclerotic etiologies

• Dissection: spontaneous (often in younger patients), or traumatic (whiplash, catheter-induced).
• Fibromuscular dysplasia: rare, more frequent in women.
• Vasculitis: Takayasu arteritis, giant cell arteritis.
• Radiation-induced stenosis: after neck/chest irradiation.
• Iatrogenic injury: after surgery or catheter-based interventions.

Vertebral artery dissection management

• Epidemiology: Common non-atherosclerotic cause of posterior circulation ischemia, especially in younger patients (<50 years).
• Clinical presentation: Neck pain, headache, posterior circulation TIA/stroke; may follow minor trauma or be spontaneous.
• Diagnosis:
• CTA or MRA with fat-suppressed T1 sequences to identify intramural hematoma.
• Consider MRI/MRA for serial follow-up.
• Medical management (first-line):
• Antiplatelet therapy (aspirin or clopidogrel) OR anticoagulation (heparin bridge to warfarin or DOACs).
• CADISS trial ^[1]: Randomized comparison showed no significant difference in recurrent stroke/TIA between antiplatelet and anticoagulation at 3 months.
• Choice is individualized based on dissection extent, pseudoaneurysm, and patient factors.
• Endovascular therapy: Reserved for patients with recurrent ischemic events despite medical therapy, or flow-limiting stenosis/pseudoaneurysm.
• Duration: Most dissections heal within 3–6 months; repeat imaging to guide duration of antithrombotic therapy.

Vertebral artery disease

• Ostial stenosis: reduces antegrade flow into posterior circulation.
• Plaque instability: risk of embolization to cerebellum/brainstem.
• Hemodynamic insufficiency: especially when both vertebral arteries or basilar artery are diseased.

Subclavian artery disease

Intervention thresholds: Revascularization is indicated for symptomatic patients with subclavian steal syndrome, upper extremity ischemia, or in preparation for LIMA-CABG or AV fistula creation. Asymptomatic stenosis generally does not require intervention.

Collateral pathways

• Circle of Willis, contralateral vertebral artery, thyrocervical and costocervical trunks.
• Explains variability in symptom severity.

Vertebral artery stenosis/occlusion

Management approach: Asymptomatic vertebral artery stenosis is managed medically. Symptomatic stenosis refractory to medical therapy may be considered for endovascular or open repair, though the benefit of routine stenting for stroke prevention remains unproven in randomized trials.

Subclavian artery stenosis/occlusion

• Upper extremity ischemia: arm claudication, coldness, weakness, fatigue.
• Blood pressure difference: >15–20 mmHg between arms.
• Bruit: supraclavicular bruit may be audible.
• Subclavian steal syndrome:
• Vertebrobasilar symptoms triggered by arm exertion (syncope, dizziness, blurred vision).
• Reversal of vertebral flow is the hallmark.

Vertebral-Subclavian Clinical Assessment

• Bilateral arm BP measurement.
• Neurological examination if posterior circulation symptoms.

Duplex Ultrasound

Assessment of steal hemodynamics: DUS with arm exercise or reactive hyperemia can classify the severity of vertebral flow reversal as latent, intermittent, or complete. In patients with prior coronary artery bypass grafting, DUS can detect dynamic changes in LIMA flow, helping to identify coronary-subclavian steal syndrome. These findings support revascularization decisions in symptomatic patients ^[2].

CTA (Computed Tomography Angiography)

• CTA and CE-MRA are both highly accurate non-invasive modalities for vertebral and subclavian artery assessment; DSA remains the invasive reference standard ^[2].
• High spatial resolution for vertebral origin and subclavian.
• Defines lesion length, calcification, and collaterals.

MRA (Magnetic Resonance Angiography)

• Alternative if CTA contraindicated.
• CE-MRA offers reliable vertebral imaging.

DSA (Digital Subtraction Angiography)

• Reference standard, but invasive.
• Now mainly used during planned endovascular treatment.
• Contemporary diagnostic stroke risk is typically ≤0.5%, varying by center and indication ^[2].

Advanced diagnostics

• IVUS: used in endovascular therapy for accurate vessel sizing.
• Transcranial Doppler: evaluates posterior circulation hemodynamics, flow reversal.

Medical therapy

• Antiplatelet therapy: aspirin or clopidogrel.
• Statins: intensive lipid lowering.
• Blood pressure and diabetes control.
• Lifestyle: smoking cessation, exercise.
• Indications:
• Asymptomatic patients.
• Mild (<50%) stenosis.
• High-risk patients unfit for revascularization.

Endovascular therapy (preferred first-line in most)

• Balloon angioplasty ± stent placement.
• Indications:
• Symptomatic subclavian artery stenosis (>50–70%) — endovascular therapy is first-line ^[2].
• Vertebral artery origin stenosis — consider in selected symptomatic patients after MDT; RCT evidence for stroke reduction is limited ^[2].
• Asymptomatic stenosis — consider in bilateral disease or when a LIMA graft is present/planned (coronary–subclavian steal risk) ^[2].
• Outcomes (subclavian): high technical success with low peri-procedural morbidity; mid-term patency ~70–85% and restenosis ~10–20% ^[2].
• Intracranial vertebral/basilar stenosis: do not stent routinely outside trials because of higher peri-procedural risk and no proven benefit over best medical therapy ^[3],[2].
• Antithrombotic therapy: DAPT (aspirin + clopidogrel) for 1–3 months after stenting, then lifelong single antiplatelet therapy ^[2].

Open surgery

• Reserved for long occlusions, young patients, or failed endovascular.
• Options:
• Carotid–subclavian bypass: prosthetic graft.
• Subclavian–carotid transposition: excellent long-term patency.
• Axillo-axillary bypass: less durable, for selected cases.
• Vertebral artery reconstruction:
• Vertebral artery transposition to the common carotid artery — indicated in young patients, long ostial occlusions, or failed endovascular therapy.
• Vertebral endarterectomy at the V1 segment for ostial disease.
• Outcomes:
• 5-year patency 85–90% for subclavian reconstruction ^[2].
• Higher perioperative risk vs endovascular.

Hybrid procedures

• Increasingly used in patients with multilevel disease (carotid + subclavian).
• Example: carotid endarterectomy + ipsilateral subclavian stenting.

Left subclavian artery management in TEVAR

• Clinical relevance: Coverage of the LSA origin is frequently required during 16TEVAR.
• Risks of LSA coverage without revascularization: posterior circulation stroke, spinal cord ischemia (via collaterals to the anterior spinal axis), and left arm ischemia.
• Indications for prophylactic LSA revascularization ^[2]: planned LSA coverage in patients with (i) absent/hypoplastic right vertebral artery, (ii) prior CABG with LIMA graft (coronary–subclavian steal risk), (iii) left arm dominance or dialysis fistula, and/or (iv) extensive aortic coverage increasing spinal cord ischemia risk.
• Revascularization options: carotid–subclavian bypass or subclavian–carotid transposition (open); selected endovascular options (e.g., chimney).
• Timing: preferably staged before 16TEVAR; concomitant in urgent/emergent settings.

Vertebral-Subclavian Follow-up

• DUS surveillance: 1 month, 6 months, 12 months, then annually; adjust intervals based on symptoms and restenosis velocity criteria ^[2],[4].
• Restenosis management: Symptomatic or hemodynamically significant restenosis (≥70%) → consider repeat endovascular therapy or bypass, individualized by lesion/anatomy ^[2].
• Medical therapy: Lifelong single antiplatelet therapy and statin; consider DAPT for 1–3 months after stenting ^[2].

Coronary-subclavian steal syndrome

• Definition: Reversal of flow in a LIMA graft due to proximal left subclavian stenosis causing myocardial ischemia.
• Frequency: Rare but clinically important; risk is increased if proximal LSA disease is present.
• Clinical presentation: angina or ACS, often precipitated by left arm exertion; some patients are asymptomatic.
• Diagnosis: bilateral arm BP (a >15–20 mmHg inter-arm difference suggests subclavian disease ^[5]); duplex can demonstrate dynamic LIMA or vertebral flow reversal with arm hyperemia; CTA defines proximal LSA lesion and conduit anatomy.
• Management: endovascular stenting of the proximal LSA is first-line; open revascularization reserved for failed endovascular or hostile anatomy ^[2].
• Prevention: in CABG candidates planned for LIMA, screen for proximal LSA stenosis and revascularize when significant before surgery, in coordination with the heart team ^[2],[6].

Vertebral-Subclavian Tables

Table 8.3. Clinical Manifestations of Vertebral and Subclavian Artery Disease

Table 8.4. Treatment Strategies

References

1. Voetsch B, DeWitt LD, Pessin MS, Caplan LR. Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry. Arch Neurol. 2004;61(4):496-504. PubMed
2. Shadman R, Criqui MH, et al. Subclavian artery stenosis: prevalence, risk factors, and association with cardiovascular diseases. J Am Coll Cardiol. 2004;44(3):618-623. PubMed
3. Patel SN, White CJ, et al. Catheter-based treatment of the subclavian and innominate arteries. Catheter Cardiovasc Interv. 2008;71(7):963-968. PubMed
4. Radak D, et al. Endovascular treatment of symptomatic high-grade vertebral artery stenosis. J Vasc Surg. 2014;60(1):92-97. PubMed
5. Naylor AR, Ricco JB, et al. ESVS 2017 Guidelines on Carotid and Vertebral Artery Disease. Eur J Vasc Endovasc Surg. 2018;55(1):3-81. PubMed
6. Mousa AY, et al. Validation of subclavian duplex velocity criteria. J Vasc Surg. 2017;65(6):1779-1785. PubMed
7. Markus HS, et al. CADISS: Antiplatelet vs anticoagulation for cervical artery dissection. Lancet Neurol. 2015;14(4):361-367. PubMed

Explicit differentiation: extracranial vertebral artery origin (VAO) stenosis vs intracranial vertebral/basilar stenosis (atherosclerotic) and how treatment differs

Key distinguishing features between extracranial and intracranial vertebral atherosclerotic stenosis include anatomic location and treatment response. Extracranial disease most often affects the vertebral origin (V1 segment) and may be amenable to stenting or surgery, while intracranial disease (V4 segment) carries a higher risk of periprocedural stroke with stenting and represents a distinct clinical entity best managed with aggressive medical therapy.

Subclavian steal syndrome: pathophysiology grading and intervention thresholds

Hemodynamic grading: Duplex ultrasound and transcranial Doppler with arm hyperemia can classify steal physiology as latent, intermittent, or complete based on the degree and timing of vertebral flow reversal.

Indications for intervention: Treatment is recommended for patients with symptomatic vertebrobasilar insufficiency provoked by arm exertion, disabling arm claudication or ischemia, planned LIMA graft or hemodialysis access in the ipsilateral arm, bilateral subclavian disease, or when TEVAR will cover the left subclavian artery.

Asymptomatic patients: Subclavian steal phenomenon without symptoms rarely requires treatment unless special circumstances exist ^[2].

Pre-CABG planning when a LIMA graft is intended: screening and timing of subclavian revascularization

In patients planned for CABG with LIMA graft, systematic screening for subclavian artery disease is recommended to prevent coronary-subclavian steal syndrome. Bilateral arm blood pressures should be measured in all CABG candidates. If an inter-arm blood pressure difference >15–20 mmHg is detected, or if the patient has a supraclavicular bruit or symptoms suggestive of subclavian stenosis, duplex ultrasound or CTA should be performed to assess the proximal left subclavian artery. When significant stenosis (>50–70%) is identified, subclavian revascularization—preferably by endovascular stenting—should be performed before CABG, with timing coordinated with the cardiac surgery team ^[2],[6].

Comparative evidence for endovascular vs open surgical revascularization for subclavian lesions

Endovascular stenting is the first-line treatment for proximal subclavian stenosis due to high technical success rates and low peri-operative morbidity, though restenosis rates of 10–20% have been reported. Open surgical options, including carotid-subclavian transposition or carotid-subclavian bypass, offer superior long-term patency (85–90% at 5 years) and are preferred for long occlusions, younger patients, or cases where endovascular therapy has failed. However, open surgery carries higher peri-operative risk. Patient selection should be individualized based on lesion anatomy, patient age and comorbidities, and institutional expertise ^[2].