First - the radiation dose from a nuclear stress test is 3 fold greater than a cardiac CT AND exposes the total body to radiation. If one goes to really cutting-edge center, the latest protocols give 1/10th the dose of a nuclear stress test. And, by the way, cardiovascular disease has killed 50% of Americans for the last 100 years!. Furthermore, the first symptom in half of men and just less than two-thirds of women is cardiovascular death - fatal heart attacks, sudden cardiac death, or fatal strokes. I think it is quite worthwhile to find this disease early, or if one does not have it, to know that without any question - and thereby avoid drugs, procedures (stress tests, caths), as well as the accompanying worry and uncertainty.

 

Second - The cost of a Cardiac CT is LESS THAN the cost of a nuclear stress test and is far more accurate. In fact, I give up money doing Cardiac CT instead of nuclear stress tests, but cardiac CT is a far better test: provides a magnitude more information, take 10 minutes instead 3 hours, is safer, and is far more accurate. In fact, what was not detailed in the article was the fact that every cardiologist knows: stress tests can only hope to identify blockages more that 70% (and they will detect them about 85% of the time). Anything less than that, and one will have a "normal" stress test. As far as the debate between stress testing accuracy versus the potential information possible from a cardiac CT, I would ask Tim Russert. Oh wait, I can't, because he died five weeks after his "normal" stress test! Furthermore, stress tests will be abnormal in about 15 to 20% of people that don't have any severe blockages AND THEN they get cathed - giving even MORE radiation, plus the risks, time, worry, and cost ($8 to $20K), only to find out that they are "normal". When we looked at our cath outcomes when we began to routinely do Cardiac CT several years ago, we found that only 25 to 30% of the patients who had standard invasive cardiac catheterization went on to any kind of an intervention (balloons, stents, surgery). The vast majority were normal OR had mild disease that didn't need an intervention, and, therefore, these patients shouldn't have been cathed in the first place! I have analyzed how much money that Cardiac CT saves over doing those caths. In my practice alone, using cardiac CT versus cath saved over 2.8 million dollars in one year! AND we got much more accurate assessments of the coronaries, and we did it easier, safer, and faster.

Third - the fascinating theme I saw when I read the story is that the docs most negative about this were generally interventional ("cathing") cardiologists! I wonder why they may be threatened by a procedure that is more accurate, provides for more information, dramatically cheaper and safer, and faster. And, where is the randomized, controlled, prospective trial of cardiac catheterization that shows that invasive cardiac catheterization (which celebrates its fiftieth anniversary this year) saves lives or prevents heart attacks? What is good for the goose should be good for the gander...

A big perspective picture? This current debate has changed radically from a just few years ago where the question was, "was this an accurate test and how does it compare to cath". That has now been well answered in the literature. Now the debate is - is this cost effective and where is the prospective data showing its value? Given that these machines have only been commercially available for 3 to 4 years, these questions will be answered. But in the big picture, this debate sounds a lot like the controversy about fecal occult blood testing (FOBT) and sigmoidoscopy versus colonoscopy. Where did that debate end up? We don't rely on FOBT and sigmoidoscopy anymore, because colonoscopy is far more sensitive, specific, and accurate. What is interesting to me then, is that all companies readily pay for an invasive colonoscopy which requires sedation and/or anesthesia, an unpleasant prep, a day of your life, and exposes one to a 0.1% chance of a colonic perforation. Yet all companies readily pay for this at age fifty (or earlier if one has a strong family history AND repeat exams in the future depending on what the test shows) for a disease that kills 50K Americans a year. Whereas we now have a very accurate (no further debate there!), fast, safe, simple, easy, and relatively inexpensive (certainly versus stress tests, caths and cheaper than a colonoscopy!) test for the disease that kills over one million people every year (or 2 per minute) in the US!

What would you rather have done for you or your family?

Best of Health!

John

 

 

John A. Osborne, MD, PhD, FACC

josborne@sothcardiology.com

As a 64 yr old male PT with 2 LAD stents 15 months apart (2 years ago) I remain very interested in trying to figure out what else I can do to to avoid any more serious cardio problems.  My cardiologist is a young, bright guy who appears to trust the nuc stress test and with my history I think he is right.  There is a father/son cardio team locally who are pushing what I think is a CT scan(?), which maybe is too late now that I have some known conditions.

 My problem is learning all the lingo, trying to sort out the ads from MD's, clinics and hospitals.  e.g. how many slices is good, what is the radiation level with each device/test, what is the cost, etc.  How is the patient to know and who can he trust with honest comps?  I don't hold any grudges knowing that MD's have to pay for their education, pay a staff, and take a few dollars home and I'm probably more well read than most patients but I just do not feel that I have enough unbiased info.  (I know -  ask my doc but he is terribly busy and the best I can get is 10-12 minutes IF I have my questions written out!) 

Mr. Kallal: it's good that you're asking questions.  This is an area that is confusing because there's no evidence to guide doctors.  If you already have stents, then you should already be on maximal anti-plaque medication.  If you're asking, "should I get a CTA to check on things?"  then the facts are clear:  there is no proof of benefit, especially if you're feeling fine without chest pain or symptoms.  Also, just because you see a narrowing doesn't necessarily mean you throw in a stent.  Some docs apparently still don't understand this.  Also, in your case, stents are a problem in CTA because the metal interferes with sharp visualization of the vessel wall.  

The facts are that CTA has no evidence of  incremental benefit.  Perhaps it will and these studies should be done.  Why it's been so controversial is because of the costs involved and because various people have basically ordering it indiscriminately.  Fortunately the ACC and SCCT quickly released appropriateness criteria -- but it's disappointing to see people still ordering them.  I heard Hecht talk and he put a CTA driven chest pain algorithm -- because he doesn't rely on evidence, I guess he can do that.

But CMS has to pay, so they have the right to rely on evidence.  The NYT article was well done.  It points out how in the US, new medical technology, like meds, often run away in use, run up costs -- and often turn out to have no or modest benefit.  CMS has the right to ask for the data before paying.  It'd be more rational to limit CT to high volume centers who will churn out the data in a few years.  I personally think CTA's potential impact may be best felt in the ER triaging chest pain.  Until then, most of the cta's being ordered now are a waste.  Anyone who wants to do a cost analysis needs to look at all these asymptomatic people getting scanned with no demonstrable benefit. 

 

 

Discover the disease is not a treatment! Before use a radiation machine to find coronary disease, we must learn to treat. We want to treat a disease without understands it. Not just the result of studies such as ENHANCE or COURAGE to confirm our intervention as inadequate?

The reason that CTA is not ready for widespread use is not radiation. Normally, we accept radiation if the benefit is great enough. The same way we think about cost-effectiveness, we can think about radiation-effectiveness. Well, we do not have evidence-based information about the effectiveness of CTA approaches in preventing cardiovascular events, like Tim Russel's sudden death.Moreover, CTA should not be seen as a substitute for cath, because it does not have the same accuracy in terms of quantifying stenosis as a numeric variables, nor evaluating coronary atherosclerosis in the sense of defining the best therapeutic approach. Thus, we need studies that compare the accuracy of CTA with non-invasive ischemia methods. Mainly, we need clinical trials that evaluate the impact of CTA strategies on clinical events. 

 

John Osborne framed it well.  However when you take his arguments and change the topic from CTA to EBT-CAC, it resounds even louder.  I feel that the arguments against coronary calcium screening are  unconcionable considering  the substantial risks of non-screeing.  Combining CAC screening with agressive primary prevention and evaluation for ischemia only in those with symptoms or CAC scores over 600 makes remarkable sense.  Unfortunately it doesn't make cents or dollars therefore those who focus on CAC screening alone are usually insolvent.  It therefore becomes necessary to use more expensive and impressive looking tests like CTA to keep the doors open. 

Anyone who critizices CAC screening or CTA based on radiation dose or financial self referral, yet performs routein nuclear stress testing on a self referral basis at a greater cost and increased radiation is a hipacrit indeed. Especially considering the relative quality of information derived from atherosclerosis imaging vs the indirect information from nuclear imaging (aka unclear imaging).

It is very important CAC screening with electron beam tomography (EBT) that its scans have significantly lower radiation exposure than MDCT scans. EBT is gold standard for CAC. EBT coronary angiogram is the first noninvasive CT coronary angiography since 1999. The significantly lower radiation dose associated with EBT angiography compared with MDCT angiography. But, EBT angiography is forgotten now in cardiology circles. I couldn't understand exactly why this safer technology was abandoned from the CT market?

I’d be curious what readers think about moving towards CTA as the first test for patients with chest pain, instead of using a nuclear perfusion study. The CTA proponents we talked to for our article, “CT Heart Scan Experts Criticize New York Times Article”, feel that this diagnostic pathway could prevent a large number of unnecessary nuclear tests, as well as invasive caths, since CTA is extremely accurate for negative predictability (98-99% in every study done so far) and could safely rule out further testing -- saving money, radiation and the risk of complications from catheterization. For example, a positive or indeterminate nuclear test almost always leads to a cath. But, according to the NCDR Cath PCI Registry, 37% of caths show no disease. According to the cardiologists we spoke with, most of these negative caths could have been eliminated by a CTA. (We’re, of course, discussing stenoses here since no imaging system yet identifies vulnerable plaque – and I agree with Dr. Topol’s comment in the NYT article about the field being too stenosis-centric.)

Thoughts?

I am interested about what the experts  would due with a 64 year old male with SOB/DOE. With a careful history it sounds likely to be from a recent viral illness/ bronchitis. He has lipid problems, on a high dose of a strong statin, obesity and HTN. A nuclear stress test is performed that is submximal, due to either a slow heart rate (he is on  low dose atenolol) or chronotropic incompetence. Would they not suggest a CTA here? Or would they do nothing and continue with aggressive medical therapy, not have ordered the stress test in the first place, or recommend him for cath?

Dear Mandell,

I suggest a CAC screening instead of CTA. If he had lowest percentile according to age, you must go on medical therapy. If his percentile value is above 75 %, you can recommend him for cath because his nuclear test is submaximal.

Regards,

I couldn't agree with Dr. Blanchet more!  Bravo!\

Burt Cohen is right on as well! First define the presence, extent, and characteristics of the disease, then firgure out how to treat it!  Isn't this how we treat cancer?  I think we in cardiology can learn a lot from our oncologist colleagues as we think about a rational way to identify and treat "Cancer of the Coronaries (TM)"

My apologies to Dr. Souza, but I think he has missed a couple of points by pointing out ENHANCE and COURAGE.  ENHANCE was a very flawed study that showed if one treated individuals with barely any demonstratable carotid disease, that it was impossible to show a difference between the two treatments, niether of which really controlled the lipid condition to a satisfactory level, frankly.  This study no way impugned atherosclerosis imaging, it did indict the study designers who should have figured out that fact.  COURAGE is actually a great example of the promise of Cardiac CTA because it was the drugs and lifestyle therapy that worked, not the expensive and risky intervention.  But rather that doing stress tests and caths to identify these patients, they should have used (but of course it didn't exist back then) CTA - much cheaper, faster, simpler, and safer!

 John Osborne

Dr. Osborne, I totally agree with your point that the COURAGE trial is a great example of the promise of CTA -- I in fact discussed this very issue with Bill Weintraub and Dave Maron, two of the COURAGE authors, shortly after the study was published. The oculo-stenotic reflex has been much talked about -- if you see a stenosis, you must stent it! But by separating the diagnostic imaging session from the intervention, which is what CTA provides, there is no possibility of "ad hoc" stenting -- cardiologists would have to stop, look at the patient and then decide, without the pressure of the cath lab schedule, what would be best for this particular patient: medical therapy, PCI, bypass, etc. Rather than cause more interventions, I (and several cardiologists I have discussed this with) feel that CTA will refine patient selection for PCI. There's usually no urgency to stent a patient, unless it's an MI, so why not take a few days to decide.

I think that primary CTA is a great choice for evaluation of chest pain as it can look for coronary disease as well as pulmonary thrombosis. As CT pulmonary angiography has become the standard for diagnosis of venous embolic disease, it seems intuative that CTA should be expanded to include the coronary arteries as the incremental cost is small and the incremental radiationi is minimal.

I disagree with Burt Cohen when he writes that "no imaging system yet identifies vulnerable plaque".  Progression of calcified plaque by serial EBT calcium imaging clearly identifies the patient with unstable plaque and high risk for a coronary event.   Stability of calcified plaque by serial EBT calcium imaging clearly identifies those with stable plaque and low risk for a coronary event. 

Early studies suggested that progressive calcification on EBT portends an inreased cardiac risk. The impact of such a finding on treatment for an asymptomatic patient is unknown. There is no evidence that progressive calcification correlated with accepted measures for vulnerability like plaque content, inflammation or cap thickness. In fact, the calcified components of plaque are generally stable. There is no clear role for serial EBT testing.

I do believe that EBT is often helpful for risk stratification, and this test can reasonably motivate intensification of therapy. But dogmatic and untested statements reduce the credibility of proponents. Imaging both calcification and "soft plaque" and perhaps signs of vulnerability in the future may prove even more helpful for risk stratification in the future.

 But until radiation goes down and data increases, there is no role for routine CTA in an asymptomatic patient. For symptomatic patients, I individualize imaging decisions, recognizing the complementary roles of identifying perfusion defects (nuclear) and anatomic stenoses (cath or CTA).

 

The most acceptable measure of plaque vulnerability is the incidence of myocardial infarction.  As stability by EBT correlates strongly with reduced events and progression by EBT correlates strongly with increased risk of events, I stand by the position that serial EBT does indeed identify vulnerable plaque and more importantly the vulnerable patient.

Benefiting form the DATA that a patient is at increased risk for an event can only be accomplished when that DATA is used to modify medical management.  I don't consider this a dogmatic or unproven statement, it is called common sense.  I understand that prospective blinded studies trump common sense but until such studies are performed, I am not ashamed of applying  common sense when the result is fewer heart attacks and less mortality.