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

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?

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).

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?

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,

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.

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).