SVC syndrome

1. • A 50-year-old woman presenting with a three-month history of
worsening shortness of breath, with associated cough, intermittent
haemoptysis and weight loss. Computed tomography (CT) of the
chest/abdomen shows a 10 × 8.5 cm superior mediastinal mass
encasing local blood vessels and right main bronchus, extending to
the right hilum, with a separate smaller right upper lobe nodule.
Supraclavicular lymph node was palpable. Fine needle aspiration of
the neck node shows small cell carcinoma. The patient re-presented
as an emergency with worsening shortness of breath and neck
swelling shortly after the scan and biopsy.
CASE HISTORY

2. Management of Superior Vena
Caval Obstruction
DR KIRAN

3. INDRODUCTION
• The first recorded description of SVC obstruction (SVCO) was in 1757
when William Hunter described the entity in a patient with a syphilitic
aortic aneurysm.
• For nearly two centuries thereafter, nonmalignant processes such as
aortic aneurysms, syphilitic aortitis, or chronic mediastinitis due to
tuberculosis were the predominant etiologic factors

4. Anatomy
• SVC originates in the chest, behind the first right sternocostal
articulation, from the confluence of two main collector vessels: Right
and Left brachiocephalic veins which receive the ipsilateral internal
jugular and subclavian veins.
• After the brachiocephalic convergence, the SVC follows the right
lateral margin of the sternum in an infero posterior direction.

5. • Finally, it enters the pericardium superiorly and flows into the right
atrium;
• No valve divides the SVC from right atrium.
• The SVC’s length ranges from 6 to 8 cm.
• Its diameter is usually 20-22 mm.

6. • The blood pressure ranges from -5 to 5 mmHg and the flow is
discontinuous depending on the heart pulse cycle.
• The SVC receives a single affluent vein: the azygos vein.
• The azygos vein joins the SVC from the right side, at its mid length,
above the right bronchus.

7. Major Systemic Veins Head and Neck
Occipital vein
↓
Posterior arcuate vein
↓
External jugular vein
↓ Vertebral
↓
Facial
Superficial temporal
vein
Subclavian vein
Brachiocephalic vein
↓
Superior vena cava
Internal jugular vein

8. Major Systemic Veins
Upper Limb
Ulnar vein Radial vein Basilic vein
Brachial vein
Cephalic Axillary
↓
Subclavian
↓
Brachiocephalic
↓
Superior vena cava
Median cubital vein
Medianantibrachial vein

10. Azygos vein
• Azygos vein transports deoxygenated blood from the posterior walls of
the thorax and abdomen into the superior venacava.
It is formed by the union of
• Ascending lumbar veins with
• Right subcostal veins
• At the level of the 12th thoracic vertebra,
• Ascending in the posterior mediastinum, and arching over the right
main bronchus posteriorly at the root of the right lung to join the
superior vena cava.

11. • A major tributary is the hemiazygos vein, a similar structure on the opposite side of
the vertebral column.
Other tributaries include
• Bronchial veins,
• Pericardial veins, and
• Posterior right intercostal veins.
• It communicates with the vertebral venous plexuses.

14. SVC obstruction
• Because of its mediastinal location and because it is surrounded by
several rigid structures including the sternum, trachea, pulmonary
artery, right main-stem bronchus, and numerous lymph nodes, the
SVC is particularly vulnerable to obstruction.
• Despite being a relatively large vessel, its thin vascular walls and low
intravascular pressure contribute to the ease with which the SVC can
be obstructed.
• SVCO can be caused by external compression due to tumor or by
lymph nodes enlarged by inflammation or metastases.
• SVCO It can be caused by direct tumor invasion or by a thrombus.

15. SVC obstruction
• In SVC obstruction, the azygos vein is responsible for the most
important collateral circulation.
According to the expected collateral pathways, the SVC can be divided
into two segments:
• Supra-azygos or preazygos and
• Infra-azygos or postazygos SVC.

16. • There are four possible collateral systems which were first described
in 1949 by McIntire and Sykes.
They are represented by
1. Azygos venous system,
2. Internal thoracic venous system,
3. Vertebral venous system and
4. External thoracic venous system.
McIntire FT, Sykes EM jr. Obstruction of the superior vena cava: Ann Intern Med 1949; 30:925.
1.

17. 1. Azygos venous system is the only direct path into the SVC.
2. Internal thoracic vein is the collector between SVC and inferior vena
cava (IVC) via epigastric and iliac veins.
3. Vertebral veins with intercostals, lumbar and sacral veins, represent
the posterior network between SVC and IVC.
4. External thoracic vein system is the most superficial and it is
represented by axillary, lateral thoracic and superficial epigastric
veins.

19. ETIOLOGY
• Since 20th century leading cause for SVCO is bronchogenic Ca.
Squamous cell ca non small cell ca accounts for >85% of SVCO.
• NON hodgkins Lymphoma- diffuse large cell lymphoma 7% and
lymphoblastic lymphoma 20%
• Metastatic cancers 5-10% from breast, germ cell tumours and
prostate.
• Thymoma, mesothelioma, primary angiosarcoma
• Non malignant accounts for 5%-

20. MALIGNANT CAUSES BENIGN CAUSES
EXTRINSIC CAUSES Lung Cancers: SCLC,NSCLC
Mediastinal
Lymphadenopathy:
NHL,Germ Cell tumours,
Medial Lymphnode
metastasis
Thymoma, esophageal ca
(rare)
Substernal Goitres
Idiopathic, Radiation
Induced ,Aortic Aneurysm
TB, Histoplasmosis,
Echinococcosis,
Syphillis,
Sarcoidosis, Behet’s disease
INTRINSIC CAUSES Tumour Invasion with clot
formation
Iatrogenic (Paed): Central
Venous Line thrombosis,
Pace makers, in dwelling
defibrillators

21. Paediatric Causes
• IN children, SVCO is most frequently related to iatrogenic causes
resulting from cardiovascular surgery for congenital heart disease or
ventriculoatrial shunts for hydrocephalus.
• The most common malignant causes of SVCO in children are non-
Hodgkin lymphoma, acute lymphoblastic leukemia, Hodgkin disease,
neuroblastomas, and yolk sac tumors.

22. Symptoms and Signs of SVCO obstruction
SYMPTOMS
Breathlessness
Headache on bending forward or
coughing
Hoarsness
Facial/Arm edema
Dizziness
Fatigue
SIGNS
• Stridor
• Distended Neck/Chest veins
• Pemberton Sign
• Plethoric complexion
• Conjunctival congestion
• Confusion

24. Pemberton Sign

25. The clinical seriousness is related to several factors:
1. Level of obstruction and rapidity of development, determining the
effectiveness of collateral circulation
2. Impairment of lymphatic drainage (pulmonary interstitial edema or pleural
effusion)
3. Involvement of other mediastinal structures (compression or invasion of heart,
pulmonary artery and central airways, phrenic nerve paralysis…)

26. Anatomic classification includes three levels of obstruction:
1. Obstruction of the upper SVC, proximal to the azygos entry point.
2. Obstruction with azygos involvement.
3. Obstruction of the lower SVC, distal to the azygos entry point.

30. Investigations
• A standard chest radiograph is the first radiographic procedure
performed when SVCO is suspected, with the most common
abnormality being mediastinal widening. Typically, a mass is found in
the superior mediastinum, right hilum or perihilar region, or right
upper lobe
• A contrast-enhanced chest computed tomography (CT) scan provides
visualization of extravascular and intravascular tumor, as well as
thrombus formation within the SVC, and also demonstrates collateral
flow.

31. Diagnostic Tests
• Radiological:
---Chest Xray
---CT Thorax
---MRI
---Contrast Enhanced Venogram
Histologic
---Lymph Node Biopsy
---Sputum or pleural cytology
---Bone Marrow Biopsy
Procedure
---Thoracotomy
---Thoracocentesis
---Broncho/Mediastinal Scopy

32. Chest Xray
Superior Mediastial
Widening
Right Hilar Prominence
Mediastinal Mass or
calcified paratracheal
lymph nodes
granulomatous disease

33. CT IMAGING
Mediastina Mass
Level of Obstruction
Intrinsic or Extrinsic
Compression
Hilar Lymphadenopathy
Pulmonary Lesion
Pleural Effusion

34. VENOGRAM
Most Conclusive test
Defines SVC obstruction
and collaterals
Identifies thrombus
Extend and degree of
obstruction
Patency of vessel

35. Treatment Over View
• Medical: Cortico Steroid and Diuretics for laryngeal and cerebral
edema , Thrombolytic and anti coagulants
• Chemoradiation : for radiosensitive tumours, such as germcell , NHL,
lung cancers
• Surgery : Bypass of obstructed SVC, mostly in very advanced disease
• Endovascular stents : for immediate relief

36. • upright position
• oxygen ,
• dexamethasone (8–16 mg daily with PPI cover),
• low-molecular-weight heparin(LMWH) in the presence of proven
thrombus.
• Diuretics have also been used with effect for the oedema associated
with SVCO

37. RT
INTENT
• To decide if its only palliative or curative
- poorer prognosis - palliative doses
underlying disease process is usually not influenced over a long
period in this situation.
- probability of cure : 2 or 3 fractions of higher doses initially to
alleviate the symptoms
followed by standard course thereafter often with concurrent
chemotherapy

38. DOSAGE
CURATIVE CASES
Depends on specific type of tumour, extent of tumour, and normal
tissue tolerance
• Prognosis and performance status.
• Curative treatment of lymphoma 3600cGy to 4400cGy if only
radiation is given.
• SCLC 4500cGy given twice daily or 6000cGy given daily with
concomitant chemotherapy.
• Non SCLC 6000 to 7000cGy sequentially or concomitant.

39. • Palliative Intent
• Schedules includes 30Gy in 10 fractions, 20Gy in 5 fractions, 30Gy in
15 fractions.

40. Conventional Borders
Conventional RT field tumors
• Supra sternal Notch
• Primary tumor + 2 cm
(Two anterior–posterior parallel–
opposed fields)
Prescirbed at mid plane

41. CONFORMAL and Curative treatment
• CTV: (primary tumor and involved nodes)
• SCC: 6 mm; adenocarcinoma: 8 mm; LN: 5 mm
• PTV:
• Upper lobes
• Right–left: CTV + 1.5 cm
• Anterior–posterior: CTV + 1.5–2 cm
• Superior–inferior: CTV + 2 cm

42. Response to Radiation
• Although radiotherapy is associated with improvement of signs and
symptoms in most patients, majority of them donot achieve
measureable increase in vena caval blood flow
• Development of collaterals probably contributes to clinical
improvement in some patients.
• This has been proved on venograms as well as autopsy studies.
• Over all 50-70% treated patients achieve symptomatic improvement
with 2 weeks of initiation of treatment

44. CHEMOTHERAPY
• SCLC: 7-12% as SVCO at prentation
• Presence of SVCO has little impact on prognosis in case of SCLC provided
treatment is started promptly.
• Cisplatin plus etoposide and concurrent chest irradiation , if performance
status is good, localized disease and no contraindication to cisplatin
• Relief of symptoms seen by 7 days and complete resolution by 14 days.
• Recur in upto 25% of patients
• NSCLC has poorer prognosis when associated with SVCO, hence treated
with chemo radiation

45. • NHL, is a systemic disease, hence chemotherapy used as first line of
manegment,
• Recurrence is seen in large cell lymphoblastic lymphoma and if size
size of mediastinal mass is > 10cm. In such setting radiotherapy is
advocated after few cycles of chemotherpay

46. Surgery
• Has a limited role
• Indicated in tumours not responding to chemo or radiation,
anticipatory survival more than 6 months or
• Caval thrombosis in recurrent SVCO, not responding to anti
coagulants and thrombolytic theraphy
• Benign diseases such as aneurysm or goiter,

47. Percutaneous stents
• Self expanding, intravascular wire, which offer relieve within 24-48
hrs depending on underlying cause of SVCO and type of stent used.
• Complications includes thrombosis, retroperitoneal hemorrhage,
cardiac arrhythmias, and possible reocclusion.
• Types of stent…Z-stent, Wallstent, Palmaz stent
• Nickel-titanium (Nitinol) alloy metallic stent are MRI compatible