Extra Cranial Carotid Stenosis-Standard Treatment Guidelines

This is a common condition, predominantly affecting the elderly, as atherosclerosis is the commonest etiology. Most common site affected are carotid bifurcation and origins of carotid and vertebral arteries. It can also occur following radiation / trauma and can also be seen in connective tissue disorders and arteritis. It causes focal or diffuse narrowing of the carotid artery depending on etiology. It often presents with transient / permanent neurological deficits. Transient Ischemic Attack, Cerebral stroke, local bruit, amaurosis fugax, previous history of neck surgery or radiation therapy are some of the clues to clinical diagnosis.

Ministry of Health and Family Welfare, Government of India has issued the Standard Treatment Guidelines for Extra Cranial Carotid Stenosis.
Following are the major recommendations :

Case definition

The diagnosis is established by vascular imaging such as color Doppler / CT angiography / MR angiography / catheter angiography. Doppler is the first screening tool. However, catheter angiography remains the gold standard in this situation. The degree of stenosis is defined in comparison with the normal distal artery diameter (NASCET Criteria / ECST CRITERIA). Symptomatic Stenosis or stenosis more than 60% is of clinical significance.

INCIDENCE OF THE CONDITION IN OUR COUNTRY

Cerebral ischemic stroke is the third leading cause of death, and carotid artery stenosis is the commonest cause of cerebral ischemic stroke. The incidence of intracranial intracranial carotid disease is also on the rise in our country and high index of suspicion and proper imaging is often helpful in detecting the disease burden.

DIFFERENTIAL DIAGNOSIS

The carotid stenosis may be caused by:
Atherosclerosis
Fibro muscular dysplasia
Arteritis
Radiation
Trauma
Dissection
Secondary to involvement in malignant tumour in the neck

PREVENTION AND COUNSELLING

Preventive measures as advised for atherosclerosis should be followed. These include:
Avoidance of smoking
Low fat diet
Regular exercise

Control of blood pressure
Control of Diabetes

OPTIMAL DIAGNOSTIC CRITERIA, INVESTIGATIONS, TREATMENT & REFERRAL CRITERIA

Diagnostic criteria / investigations –
Stenosis greater than 60% by NASCET criteria in symptomatic individuals and greater than 70% in asymptomatic individuals are presently considered as indications for interventional treatment.

The imaging modalities used are:
1. Color Doppler
2. CT Angiography
3. MR Angiography
4. Catheter angiography

Treatment-It can be treated by endovascular stenting or surgical endarterectomy. Both modalities have shown similar results. However in non atherosclerotic etiology / difficult surgical access / high risk cases for surgery, stenting is of choice. Recent cerebral infarction is a relative contraindication. The procedure may need to be deferred for 3 weeks in such cases.

Follow up-Color Doppler is the preferred imaging modality for follow up.

Situation 1: At Secondary Hospital / Non-Metro situation: Optimal Standards of Treatment in situations where technology and resources are limited.

a) Clinical Diagnosis: Transient Ischemic Attack, Cerebral stroke, local bruit, amaurosis fugax, previous history of neck surgery or radiation therapy are some of the clues to clinical diagnosis.

b) Investigations: Hemoglobin, Total and Differential Leucocyte counts, ESR, Blood Sugar, INR, Platelet count, Serum Creatinine,

Imaging : Diagnostic criteria / investigations -

Stenosis greater than 60% by NASCET criteria in symptomatic individuals and greater than 70% in asymptomatic individuals are presently considered as indications for interventional treatment. The imaging modalities used are:

1. Color Doppler
2. CT Angiography
3. MR Angiography
4. Catheter angiography

Treatment:It can be treated by endovascular stenting or surgical endarterectomy. Both modalities have shown similar results. However in non atherosclerotic etiology / difficult surgical access / high risk cases for surgery, stenting is of choice. Recent cerebral infarction is a relative contraindication. The procedure may need to be deferred for 3 weeks in such cases.

Standard operating procedure

a. In Patient - All cases should be treated as in patients
b. Out Patient - Not applicable
c. Day Care - Not applicable
d. Referral criteria :

Stenosis greater than 60% by NASCET criteria in symptomatic individuals and greater than 70% in asymptomatic individuals are presently considered as indications for interventional treatment.

If facilities for standard treatment are not available, patient is referred to super specialty hospital where these facilities are available.

Situation 2 : At super specialty facility in metro location where higher-end technology is available.

Clinical Diagnosis: Transient Ischemic Attack, Cerebral stroke, local bruit, amaurosis fugax, previous history of neck surgery or radiation therapy are some of the clues to clinical diagnosis.

Investigations: Hemoglobin, Total and Differential Leucocyte counts, ESR, Blood Sugar, INR, Platelet count, Serum Creatinine,

Imaging : Diagnostic criteria / investigations

Stenosis greater than 60% by NASCET criteria in symptomatic individuals and greater than 70% in asymptomatic individuals are presently considered as indications for interventional treatment. The imaging modalities used are:

1. Color Doppler


2. CT Angiography


3. MR Angiography


4. Catheter angiography

Treatment: It can be treated by endovascular stenting or surgical endarterectomy. Both modalities have shown similar results. However in non atherosclerotic etiology / difficult surgical access / high risk cases for surgery, stenting is of choice. Recent cerebral infarction is a relative contraindication. The procedure may need to be deferred for 3 weeks in such cases.

Standard operating procedure

In Patient - All cases are to be treated as in patients. They should be treated in centers equipped with Digital Subtraction Angiography equipment (DSA) with roadmap facility, facility of ICU care.

Out Patient - Not applicable

Day Care - Not applicable

Referral criteria : Stenosis greater than 60% by NASCET criteria in symptomatic individuals and greater than 70% in asymptomatic individuals are presently considered as indications for interventional treatment.

SITUATION	HUMAN RESOURCES	INVESTIGATIONS	DRUGS & CONSUMABLES	EQUIPMENT
1.	Doctors – 3 (Radiologists (specialist trained in Neuro - interventional procedures-1, Anaesthetist -1, Neurologist for clinical management – 1) Technicians –1 Nurses – 1	Hemoglobin, Total and Differential Leucocyte counts, ESR, Blood Sugar, INR, Platelets, Serum Creatinine	1. Drugs: Aspirin, Clopidogrel, Nitroglycerine, Nimodipine, Heparin, Non-Ionic Iodinated contrast media 2. Consumables: Arterial access sheath, 90 cm long sheath, Guiding catheter, Self expanding carotid stent, Pre and post dilatation angioplasty balloon catheter, diagnostic angiography catheter, appropriate 0.014” & 0.035” guidewires, exchange length 0.035” guidewire, Tuhoy SBorst Y connector, Indeflator, saline Pressure flush bag, distal (or proximal) protection device	Digital subtraction angiography system (DSA) Colour Doppler Ultrasound Multiparameter patient monitor Resuscitation equipment
2.	Minimum Same as mentioned above. In addition, Intensivist- 1(desirable)	Same as mentioned above	Same as mentioned above	Same as mentioned above. In addition ACT machine ( for activated clotting time determination) is desirable.

Guidelines by The Ministry of Health and Family Welfare :

Dr. Chander Mohan
Dr. B.L. Kapur Hospital
New Delhi