2018.08.31 05:51
Patients with stable chest pain referred to a cardiology clinic for evaluation were randomized to receive standard care alone or standard care plus coronary computed tomographic angiography (CTA) to evaluate the effect of CTA on outcomes at 5 years. The rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years was 2.3% in the CTA group vs 3.9% in the standard care group (P=.004). The rates of invasive coronary angiography and coronary revascularization were higher in the CTA group than in the standard care group in the first few months of the study, but there was no difference in the rates of coronary angiography or coronary revascularization over 5 years. More preventive and antianginal therapies were initiated in the CTA group than in the standard care group.
The use of CTA in addition to usual care for patients with stable chest pain resulted in a significant reduction in death from coronary heart disease and nonfatal myocardial infarction at 5 years without increasing the rates of coronary angiography or coronary revascularization.
David Newby and the SCOT-Heart investigators now report on the 5-year long-term follow-up data of their trial, a randomized comparison of diagnosis and management based on coronary CT angiography (CCTA) results vs standard of care (mostly exercise ECG). Their initial results published in 2015 in The Lancet showed better diagnostic certainty of angina/CAD for the patients randomized to CCTA.1The follow-up reported in that paper (average, 1.7 years) showed a trend toward fewer fatal or nonfatal myocardial infarctions (MI) in the CCTA group. In the current paper, with much longer follow-up, the authors report a 41% reduction in coronary heart disease death or nonfatal MI, driven entirely by the MI component. Importantly, in contrast to many previous studies, the group randomized to CCTA did not have an excess of catheterizations or revascularizations. This is the first study to show an impact on outcomes within the context of a randomized trial of testing strategies.
The magnitude of reduction in MI is quite large and, in fact, exceeds that observed in many therapeutic trials. Mechanisms or explanations can be challenging to discern from randomized comparisons of diagnostic testing. It is unlikely that revascularization played a role, as the incidence was balanced across the groups and, in general, revascularization does not reduce MI risk in stable outpatients. More likely is the better use of medications such as aspirin and statins in the CCTA group, as the presence of CAD—even nonobstructive CAD—would have been more obvious in a greater number of patients compared with exercise ECG.
Should all patients with suspected CAD now have a CCTA as their initial test, with the expectation of better outcomes? The SCOT-Heart data are in contrast to those of the PROMISE trial, a randomized comparison of anatomic imaging with CCTA vs functional testing as the initial approach in such patients.2 In PROMISE, over 2 years of follow-up, no difference in outcomes was observed. Although patients in both trials had CCTA-based management as one randomization arm, the difference in the trials was the comparator arm. In SCOT-Heart, the comparator was predominantly exercise ECG (only ~10% of patients had an imaging stress test, nuclear, or echo), whereas, in PROMISE, the comparator was predominantly stress imaging (only ~10% of patients had exercise ECG). One might interpret the totality of results from these two trials as there is now little role for exercise ECG in outpatients with suspected CAD, and stress imaging or CCTA should lead to similar outcomes.
Another general message is the importance of aggressive preventive measures when CAD is suggested so that the testing results can drive management well beyond simply being used for diagnosis of CAD.
2018.08.31 07:54
2018.08.31 14:05
"The rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years
was 2.3% in the CTA group vs 3.9% in the standard care group ..."
Here, the standard group means "neglected" group or those who can afford the expensive test.
So, naturally, the outcome should be worse. We don't need the damn study to prove this.
This article looks like a pure commercial for CTA propaganda and sales pitch.
I like to know how much it costs to run a single CTA,
not to mention a series of multiple CTAs.
Who will get enriched by these at whose expense?
What's the difference between 2.3% and 3.9%?
It is not "substantial" as they claimed. It is insignificant statistically.
After all, CTA is not a treatment per se.
If the "Standard care group" gets more diligent medical followup and treatment,
the difference can be completely erased or maybe even reversed.
2018.08.31 22:45
The cost analysis of CT coronary angiogram has been done and published, I believe.
The last time I checked, which was some years ago, the cost of CT coronary angio was
$1200 or so, about half of what it cost to do isotope nuclear stress test and about twice
as much as a stress echocardiogram.
Nowadays most cardiologists believe CT coronary angiogram is the most effective way
dealing with significant chest pain suspected of cad in terms of life saving, money saving
and time saving when compared to the conventional, standard way that calls for multiple
visits to doctor's office or hospital outpatient clinic for stress echo or nuclear stress test
and multiple consultations, all of which are costly and time consuming.
FYI you do only one CTA, almost never multiple.
If one CTA does not give you clear answer in regard to the severity of the stenosis,
you do a selective coronary angio and prepare the patient for the possibility of coronary stenting
at the same time.
The greatest value of CT coronary angio lies in negative result and ruling out a significant CAD.
If you find mild to moderate cad that does not require stenting, you initiate medical therapy to prevent
AMI resulting from coronary thrombosis that may develop on unstable plaques.
This is what this article and my comment are about, I believe.
I feel that this information above is very important.
As pointed out clearly by the authors and the commentary,
When a patient presents with a suspicious stable chest pain
or angina, CT coronary angiogram provides not only quick
definitive diagnosis but also improves the patient's long term
prognosis by alerting the treating doctor to initiate preventive
measures to prevent acute MI.
What has been one of the most difficult challenges for the physician
is the fact that many acute MIs result from mild to moderate
cad with less than 50% stenosis and coronary thrombosis
developing on top of unstable plaque and occluding the lumen.
Aspirin will certainly help prevent the thrombosis to a degree
in these patients.
The irony or paradox is that the MI starting with smaller plaque
with 30% stenosis will be much bigger or larger than the MI
deveoping with a large plaque and 90% stenosis because
the former has no protective collaterals but the latter
has good protective collaterals minimizing the myocardial damage.
As a matter of fact, many patients have total occlusion, let's say total
occlusion of RCA or LC, and never experienced acute MI
because they developed stenosis and occlusion so gradually that
there was enough time for the collaterals to develop to prevent MI.
You can see now why medical therapy is so important in improving
the patient's prognosis independent of the revascularization such as
stenting and CABG.