Subclavian Steal Syndrome, A Simple Guide To The Condition, Diagnosis, Treatment And Related Conditions

This book describes Subclavian Steal Syndrome, Diagnosis and Treatment and Related Diseases
Sub-clavian steal syndrome is a syndrome of symptoms linked to arterial insufficiency in the vertebral artery branch of the sub-clavian artery stemming from flow reversal, due to obstructive disease in the sub-clavian artery proximal to that vertebral artery branch.
To put it simply:
If there is obstruction in the left sub-clavian artery, there is no blood flow in the left vertebral artery to the brain and arm. Both the brain and arm may be affected.
Blood from the right vertebral artery then enters left vertebral artery and flows back to supply the left arm, instead of going to the brain.
While such a blockage of blood circulation in the neck can cause the blood flow in the opposite direction in the vertebral artery (from the brain), this results in the blood stolen from the brain and can cause disturbances in the brain's blood circulation and manifest itself as a drop attack.
The syndrome can cause symptoms such as episodes of acute vertigo.
It can also produce discomfort in the arm.
Classification
The sub-clavian steal phenomenon has been typically featured either by:

1. The territory from which the blood is "stolen" or
2. The severity of hemodynamic disturbances in the vertebral artery.
   The severity is classified into 3 stages or grades:
3. Grade I (pre-sub-clavian steal): reduced antegrade vertebral flow,
4. Grade II (intermittent/partial/latent): alternating flow antegrade flow in the diastolic phase and retrograde flow in the systolic phase,
5. Stage III (permanent/advanced): permanent retrograde vertebral flow.
   A recent study has shown that the prevalence of a complete steal increases with higher arm blood pressure differentials (PD).
   The study discovered that an arm PD >40 mm Hg was linked with significantly higher incidence of partial and complete steal, with a higher proportion of the latter.
   Causes:
6. Atherosclerosis is the most frequent cause of sub-clavian stenosis and steal syndromes
7. Large artery vasculitis, thoracic outlet syndrome, and stenosis after surgical repair of aortic co-arctation or tetralogy of Fallot are other likely causes.
8. Congenital anomalies, such as a right-sided aortic arch with an isolated left sub-clavian artery, can also cause sub-clavian narrowing and steal syndromes
   More unusual causes of sub-clavian steal are:
   1.Takayasu's arteritis (large artery vasculitis),
   2.Injury after surgery or radiation therapy,
   3.Tumor of the chest cavity (mediastinal tumors),
   4.Damage to blood vessel wall and
   5.Anatomical anomalies of blood vessels.
   Symptoms
   Sub-clavian stenoses are most often asymptomatic
   Vertebrobasilar insufficiency manifests typically as "drop attacks" but may also present as:
9. Dizziness,
10. Diplopia,
11. Nystagmus,
12. Tinnitus or even hearing loss.
    Decreasing circulation to the arm can be presented as:
13. Weakness,
14. Pain through the use of the arm,
15. Tingling sensation or
16. Coldness in the arm.
    Diagnosis
    By evaluating blood pressure of both arms, the doctor will find a lower blood pressure on one side.
    There will also be decreased or absent pulse in the wrist of the same arm.
    The non-invasive Color-coded Doppler or transcranial Doppler ultrasonography is now regarded as the screening tool for sub-clavian steal
    Treatment
    When the sub-clavian steal syndrome has no or only scanty symptoms, a wait and watch treatment is indicated
    When there are distressing symptoms, the patient should be assessed for surgery to widen the stricture of a vessel such as endovascular stenting or sub-clavian bypass surgery
    Angioplasty and stenting is the favored surgical choice due to high success rates and low risks.

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