CORONARY ARTERY DISEASE: CORONARY CTA FOR OPTIMAL EARLY DETECTION, SCREENING, AND HEART ATTACK PREVENTION
Robert Schwartz MD, FACC, FAHA, FSCCT
President, Jon DeHaan Foundation
FACTS: CORONARY ARTERY DISEASE
Coronary Artery disease is the number ONE cause of death globally: more people die annually from CVDs than from any other cause.
Coronary heart disease is now the leading cause of death worldwide. An estimated 3.8 million men and 3.4 million women die each year from CHD. In developed countries heart disease is the leading cause of death in men and women.
Coronary heart disease accounts for about 15% of all US deaths, over 400,000 annually.
According to recent data the annual incidence of heart attack in the US is 605,000 new attacks and 200,000 recurrent attacks
Cardiovascular diseases (CVDs) are the number 1 cause of death globally, taking an estimated 17.9 million lives each year.
These are diseases of the heart and blood vessels and include coronary heart disease, disease brain vasculature, rheumatic heart disease and other conditions.
Four of 5 CVD deaths are due to heart attacks and strokes, and one third of these deaths occur prematurely in people under 70 years of age.
An estimated 17.9 million people died from CVDs in 2016, representing 31% of all global deaths. Of these deaths, 85% are due to heart attack and stroke.
Over three quarters of CVD deaths take place in low- and middle-income countries.
Out of the 17 million premature deaths (under the age of 70) due to noncommunicable diseases in 2015, 82% are in low- and middle-income countries, and 37% are caused by CVDs.
Most cardiovascular diseases can be prevented by addressing behavioural risk factors such as tobacco use, unhealthy diet and obesity, physical inactivity and harmful use of alcohol using population-wide strategies.
People with cardiovascular disease or who are at high cardiovascular risk (due to the presence of one or more risk factors such as hypertension, diabetes, hyperlipidaemia or already established disease) need early detection and management using counselling and medicines, as appropriate.
DETECTING CORONARY ARTERY DISEASE: THE IMPORTANCE OF CORONARY CTA
Coronary computed tomographic angiography (coronary CTA) can characterize coronary artery disease, including high-risk plaque.
It is the BEST noninvasive method of identifying high-risk arterial plaque before major adverse cardiovascular events (MACE) (heart attack and stroke) occur
It is a quantum leap forward in Cardiovascular clinical practice.
Several studies evaluated high-risk plaque as detected by coronary CTA was associated with incident Heart Attack and Stroke independently of significant stenosis (SS) and other cardiovascular risk factors such as cholesterol and lipid measures
One important study of CT was called the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial.
It examined stable, symptomatic outpatients in this trial who required noninvasive cardiovascular testing and received coronary CTA were included and followed up for a median of 25 months.
Core laboratory assessment of coronary CTA for Severe stenosis and high-risk plaque.
The study included
4415 patients, (48% men and 52% women)
mean age 60.5 years
a median atherosclerotic cardiovascular disease (ASCVD) risk score of 11,
MACE rate of 3% (131 events).
The PROMISE study results
676 patients (15.3%) with high-risk plaques, and 276 (6.3%) had SS.
high-risk plaque found in these patients was associated with a high heart attack and Stroke rate
Presence of high-risk plaque increased MACE risk among patients with nonobstructive coronary artery disease relative to patients without high-risk plaque
THE PROMISE STUDY: CONCLUSIONS AND RELEVANCE
High-risk plaque found by coronary CTA was associated with a future MACE in a large US population of outpatients with stable chest pain.
High-risk plaque by CTA is a good additional risk stratification tool, especially in patients with nonobstructive coronary artery disease, younger patients, and women.
An Additional Study:
Coronary CTA Improves Important Patient Outcomes Compared with Functional Testing: The Value of Nonobstructive CAD to Guide Post-Test Management
Numerous large-scale randomized, controlled comparative effectiveness trials, such as PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain; n = 10,003) and SCOT-HEART (Scottish Computed Tomography of the Heart; n = 4,146), established that coronary CT is as good or (probably) better than prevention strategies the do not utilize coronary CTA for all studied cardiovascular outcomes.
Coronary CT is consistently reduces incident myocardial infarction (MI) in both acute and stable chest pain populations.
In a meta-analysis of randomized trials, stable chest pain patients who underwent coronary CTA were noted to have a 31% lower risk for MI, a finding consistent across the 3 trials, including PROMISE and SCOT-HEART (I-squared = 0%).
These results demonstrate the impact of visualizing coronary plaque by CTA has on subsequent improved utilization of preventive therapies such as aspirin and statins.
For example, in SCOT-HEART, not only did coronary CTA improve diagnostic certainty for patients and providers regarding the etiology of the patients' presenting symptoms (primary outcome), but also patients who underwent coronary CTA had a fourfold increase in the use of aspirin or statin therapy.8 These test-driven changes in post-test management related primarily to visualization of nonobstructive CAD resulted in a 50% reduction in incident MIs within fewer than 2 years of follow-up.
In addition to CAD location and stenosis severity, plaque composition and morphology may further enhance the prognostic yield from coronary CTA.
The PROMISE trial found that high-risk plaque found by CTA was associated with significantly increased risk of major adverse cardiac events even after adjustment for risk factors and stenosis severity.
The prognostic importance of high-risk plaque was especially apparent among subjects with nonobstructive CAD on CTA among this low-intermediate risk cohort (33% with 10-year atherosclerotic cardiovascular disease risk <7.5%).
These findings show the superiority of CT over stress testing since CT accurately quantifies the presence, extent, angiographic severity, and composition of coronary atherosclerosis
Importantly, CT measures of CAD consistently outperform traditional risk factors (stress testing, cholesterol measurement etc) for predicting long-term cardiovascular outcomes and may better identify patients most likely to benefit from aggressive preventive medications and lifestyle interventions.
CORONARY CTA: HIGH DIAGNOSTIC ACCURAY; RARELY MISSES SEVERE HIGH-RISK CAD
Coronary CTA has the highest diagnostic accuracy compared with all available noninvasive tests for the detection of angiographically significant stenosis on invasive coronary angiography (ICA).
These findings suggest that further efforts to improve the specificity of coronary CTA, such as selective utilization of CT-derived FFR, CT perfusion, or post-CTA functional testing, may improve even further
Stress testing such as exercise treadmill tests, in selecting patients for ICA are inferior to CT and are also imprecise. For example, regardless of the noninvasive functional test utilized, less than 50% of patients referred for ICA in the United States are found to have obstructive CAD.
CONCLUSIONS ABOUT CT IN DETECTION OF CORONARY ARTERY DISEASE
Based on its high accuracy, characterization of subclinical and flow-limiting CAD, and the results from numerous large-scale, randomized comparative effectiveness trials, coronary CTA should be considered as the test of choice in most symptomatic patients without known CAD.
Unfortunately, coronary CTA is markedly under utilized. coronary CTA should at least always be an option available to patients and providers. That would be a NICE step forward to improving the value of noninvasive testing pathways in patients with stable chest pain.
Coronary CT-Angiography adds values over CCS in terms of providing quantification of total and non-calcifying coronary plaque burden (SIS and ncSIS score) and stenosis graduation (mild, intermediate and severe). Our study shows that beyond coronary calcium, non-calcifying plaque burden as well predicts outcome.
HOW MIGHT THIS IMPACT ON CLINICAL PRACTICE?
Coronary CT-Angiography should be considered in asymptomatic patients with high life-time risk of CAD as more accurate screening tool for CAD due to its ability to detect non-calcifying plaques and to quantify plaque burden (SIS and ncSIS score), as well as coronary stenosis severity graduation.
Coronary CT shows better prognostic value for cardiac events than coronary artery calcium scores and conventional risk factors
This marked improvement will carry over to less cardiac disability, improved quality of life, and improved survival
Substantial economic advantages are thus available directly due to Coronary CT and its ability to reduce morbidity and mortality.