What is ECAQ ?
ECAQ which stands for Extra-Cranial Carotid Atherosclerosis Quantification, attempts to improve upon the CIMT technique for better risk prediction. The concept and term “ECAQ” were developed by Drs Gregory Pokrywka and Thomas Barringer MD. Total Plaque Volume (TPV) and “Plaque Score” (the total number of focal plaques of any thickness > or = to 1.5 mm) have been found to be good predictors of future ascvd events, and superior to the often-used standard CIMT technique alone. TPV is estimated from CIMT data by measuring an “All Segments CIMT” Mean-Max value. An “All Segments CIMT” Mean-Max value > 75% percentile for the patient’s age and gender (or other measures of carotid plaque quantity/ volume > 75% percentile) is associated with at least a two-fold increased risk of developing cardiovascular disease events above the level estimated by traditional risk factors, such as the Framingham risk Score. . A “Plaque Score” of 2-6 increases risk of CHD almost as much as a CAC score of 100-399. Such findings usually warrant intensification of preventive therapies for intermediate risk patients, and this level of disease should be considered a “high risk patient” per ACC AHA 2018 Guidelines.
Patient Evaluation Guidelines - Who should get ECAQ ? i, ii, iii
1) ACC AHA 2019 Primary Care Prevention Guidelines recommend screening for subclinical atherosclerosis when risk decision after use of the 2018 AHA ACC ASCVD risk decision tree and calculator is uncertain or intermediate. The presence of significant subclinical atherosclerosis reclassifies the patient to a “high risk” category. ” This type of patient should be treated aggressively per ACC AHA 2018 Guidelines for “high risk patients” (usually high intensity statin therapy (>50% LDL-C reduction). Many young adults who face a low short-term risk of CVD according to 2018 ACC AHA Guidelines definitions, nevertheless may have early signs of atherosclerosis that suggest their LIFETIME risk of CVD is much higher.
2) In the setting of modulating factors (e.g. age, family history of premature CVD), as well as the presence of multiple or poorly controlled risk factors, clinicians may consider repeat ECAQ in 2-4 years to further evaluate cardiovascular risk. The benefit of serial ECAQ testing and its components of TPV and Plaque Score has not been established.
3) Examples of patient for whom ECAQ testing may not be useful are patients who are extremely elderly, secondary prevention patients and patients with an already established significantly abnormal CAC.
Advantages of ECAQ vs Cardiac Calcium Score (CAC)
• Convenience of having the procedure performed in the referring physician’s office.
• Patients who are concerned about repeated exposure to ionizing radiation (utilized to perform CAC).
• ECAQ can be used to stratify risk in anyone; CAC has limited use in populations in which the prevalence of a zero score is high (e.g. men <45 and women <55 years old. Although CAC is more predictive of CVD in the short-term than ECAQ, in young people or adults likely to have a zero CAC due to lipid rich non calcified plaque, ECAQ along with AHA ACC 2018 Guidelines risk assessment can be used to provide a more accurate estimate of long-term (“lifetime”) risk.
• ECAQ is a simple noninvasive way to further inform those patients who are reluctant to receive lifestyle modification therapy and/or pharmacotherapy, based on lab results alone of their atherosclerotic risk burden and CVD risk. Several small studies have shown that physicians were more likely to make pharmacologic therapy changes when subclinical atherosclerosis assessment was available, and that patients shown their subclinical atherosclerosis assessment values were more likely to make therapeutic lifestyle changes.
Patient Management Recommendations
The objective of ECAQ testing is to improve risk stratification in order to target treatment efforts more efficiently. The evidence mandates continuing and more aggressive use of lipid lowering regimens, and intervention at an earlier stage of the atherosclerotic process. Recommendations provided might include therapeutic lifestyle changes, pharmacotherapy modification or referral to Clinical Lipid Specialist. For example, those patients with Metabolic Syndrome unwilling to make significant therapeutic lifestyle changes can be encouraged to make these changes with more urgency when their ECAQ shows higher than expected risk. As another example, a Total Plaque Volume > 75% percentile for the patient’s age and gender (or other measures of carotid plaque quantity/ volume > 75% percentile) is associated with at least a two-fold increased risk of developing cardiovascular disease events above the level estimated by traditional risk factors, such as the Framingham risk Score. . A “Plaque Score” of 2-6 increases risk of CHD almost as much as a CAC score of 100-399. Such findings usually warrant intensification of preventive therapies for intermediate risk patients, and this level of disease should be considered a “high risk patient” per ACC AHA 2018 Guidelines. This type of patient should be treated aggressively per ACC AHA 2018 Guidelines for “high risk patients” (usually high intensity statin (>50% LDL-C reduction). Advanced lipoprotein testing with apoB or LDL-P will improve risk management over the use of lipid parameters, especially if the patient has cardio-metabolic risk (insulin resistance, Metabolic Syndrome, PCOS, diabetes, etc.) Lipid Specialists obtain and expertly utilize such parameters on a routine basis.
ECAQ Procedure Protocol
ECAQ Scanning procedure is very similar to that of a diagnostic carotid duplex. The patient is placed supine in a comfortable position and allowed to rest for 8-10 minutes before measurements are made. The CCA common carotid, carotid bulb and proximal internal carotid artery are imaged with a high resolution probe. Both sides are evaluated and reported on. The exam may take up to 30 minutes.
ECAQ Report
The final report will include the following data:
● CIMT values
● Total Plaque Volume -%tile risk ( > or < 75%tiles, adjusted for age and gender)
● Assessment of “Plaque Score “ (the total number of focal plaques of any thickness > or = to 1.5 mm). A “Plaque Score” of 2-6 increases risk of CHD almost as much as a CAC score of 100-399
● Plaque morphology, Doppler velocity and % Stenosis, when applicable.
● Clinical recommendations based on ECAQ.
