Screening and diagnosis

Classification and risk stratification

Perioperative care

Quality improvement

Patient education

Nonpharmacologic interventions

Therapeutic procedures

Respiratory support

Follow-up and surveillance

Specific circumstances

Preventative measures

Medical management

Surgical interventions

Inpatient care

Diagnostic procedures

Diagnostic investigations

Insufficient evidence to make a recommendation.

Strongly favor this test or intervention.

The SRU classification for internal carotid artery stenosis uses two main inputs: the peak systolic velocity (PSV) of the internal carotid artery measured in cm/sec and the estimated plaque percentage. Based on these inputs, the calculator provides an interpretation of the degree of stenosis, identifying potential conditions affecting the carotid artery. Below is a detailed explanation of the computation process and interpretation possibilities.

Inputs:
1. Internal Carotid Artery Peak Systolic Velocity (PSV)
   - Options: "< 125", "125-230", "> 230", "High, low or undetectable", "Undetectable"
2. Plaque Estimate (in percentage)
   - Options: "None", "< 50", ">= 50", "Visible", "Visible, no detectable lumen"

The calculator evaluates the inputs through a series of logical conditions to determine the stenosis level, as follows:

| Condition (PSV and Plaque) | Interpretation                             |
|----------------------------|--------------------------------------------|
| < 125 and Undetectable     | Normal internal carotid artery             |
| < 125 and None             | Degree of stenosis is < 50%                |
| 125-230 and < 50           | Degree of stenosis is 50-69%               |
| > 230 and < 50             | Degree of stenosis is >= 70%               |
| High/low/undetectable and >= 50 | Near occlusion                         |
| Undetectable and Visible   | Total occlusion                            |

In conclusion, this calculator helps to classify the stenosis level based on PSV and plaque visibility, assisting in identifying normal conditions versus various degrees of stenosis or occlusion in the carotid artery. If no condition matches, further analysis with additional parameters is recommended.

The calculator in question is the SRU (Society of Radiologists in Ultrasound) classification of internal carotid artery stenosis. This classification system is used in the evaluation of patients with suspected carotid artery disease, specifically to quantify the degree of stenosis or narrowing in the internal carotid artery. 

The SRU classification is particularly useful in the management of patients with cerebrovascular disease, as it helps clinicians to stratify the risk of stroke and guide treatment decisions. It is based on ultrasound findings, including peak systolic velocity (PSV), end-diastolic velocity (EDV), and the ratio of these velocities in the internal carotid artery to those in the common carotid artery.

There are no specific exclusion criteria for the use of the SRU classification. However, it should be noted that this classification system is most accurate when used in conjunction with other clinical and imaging findings. It may be less accurate in patients with tandem stenosis (stenosis in more than one location), near-occlusion with minimal residual lumen, or in cases where technical factors limit the quality of the ultrasound examination.

SRU classification of internal carotid artery stenosis

Carotid artery stenosis

Technical considerations for endarterectomy

Technical considerations for endarterectomy (high ICA lesions)

Indications for screening

Indications for screening, before cardiac interventions

Carotid endarterectomy

Carotid endarterectomy, asymptomatic patients

Technical considerations for endarterectomy (completion imaging)

Patients with abdominal aortic aneurysm

Patients with AAA

Technical considerations for stenting

Technical considerations for stenting (cerebral protection)

Carotid endarterectomy, symptomatic patients

Management of diabetes mellitus

Technical considerations for endarterectomy (wound drainage)

Carotid artery stenting

Carotid artery stenting, symptomatic patients

Hospital requirements

Follow-up imaging

Follow-up imaging, after revascularization

Patients with carotid artery coils and kinks

Technical considerations for endarterectomy (carotid exposure)

Carotid artery imaging

Patients with vertebral artery stenosis

Indications for screening, general population

Timing of revascularization

As per AANN/AANS/ACC/…/SVS 2011 guidelines, 

Perioperative antiplatelet therapy

Perioperative antiplatelet therapy, carotid endarterectomy

Patients with carotid webs

Patients undergoing non-cardiac surgery

Patients undergoing non-cardiac surgery (preoperative evaluation)

Lifestyle modifications

Patients with atrial fibrillation

Patients with AF

Intravenous thrombolysis

Follow-up imaging (medically treated patients)

Management of perioperative stroke

Patients with coronary artery disease

Perioperative antihypertensive therapy

Management of hypertension

Management of recurrent carotid stenosis

Carotid artery stenting, asymptomatic patients

Catheter-based contrast angiography

Management of postoperative neck hematoma

Anticoagulant therapy

Perioperative antiplatelet therapy, carotid artery stenting

Patients with common carotid/innominate artery disease

Technical considerations for stenting (pre- and post-dilatation)

Indications for screening (before AAA repair)

Technical considerations for stenting (premedication)

Technical considerations for stenting (choice of stent)

Management of perioperative hemodynamic instability

Clinical follow-up

Perioperative statin therapy

Indications for revascularization

Indications for revascularization (asymptomatic patients)

General principles

Technical considerations for endarterectomy (anesthesia)

Cranial artery imaging

Extracranial-intracranial bypass surgery

Technical considerations for stenting (arterial approach)

Patients undergoing non-cardiac surgery (preoperative statins and antithrombotics)

Public health measures

Antiplatelet therapy

Vertebral artery imaging

Indications for revascularization (symptomatic patients)

Technical considerations for endarterectomy (heparin reversal)

Management of carotid patch/stent infection

Management of dyslipidemia

Perioperative assessment

Technical considerations for endarterectomy (closure)

Patients undergoing non-cardiac surgery (carotid revascularization)

Patients undergoing non-cardiac surgery (timing)

Technical considerations for endarterectomy (carotid sinus nerve block)

Updated 2024 ESC guidelines for the diagnosis and management of carotid artery stenosis


Carotid artery stenosis

Background

Overview

Guidelines

Key sources