Most Popular Angioplasty Web Site
Angioplasty.Org Interview Series:
James K. Min, MD, FACC
Email Bookmark and Share
James K. Min, MD, FACC, is Director of Cardiac CT labs at Weill-Cornell Medical College, New York-Presbyterian Hospital, and specializes in the diagnosis of coronary heart disease with multidetector CT angiography. He also has expertise in echocardiography, nuclear cardiology and the identification of novel clinical risk factors that place individuals at higher risk for the development of coronary heart disease.

Dr. Min is a member of the Board of Directors of the Society for Cardiovascular Computed Tomography (SCCT). He received his medical degree from Temple University School of Medicine and completed his internship, residency, and cardiology fellowship at the University of Chicago Hospitals. Dr. Min is Assistant Professor of Medicine, Division of Cardiology and Assistant Professor of Radiology at the Weill Cornell Medical College and the New York Presbyterian Hospitals in New York City.

He lectures both nationally and internationally on cardiac CT, has conducted the CT Cardiac Masters Series for the GE Healthcare Institute and has appeared on national television to discuss the impact of cardiac CT on clinical cardiology practice. He is co-author of the Cardiac CT Atlas.



James K. Min, MD, FACC
James K. Min, MD, FACC
NewYork-Presbyterian Hospital

Q: Where would you place coronary CT angiography right now in the spectrum of diagnostic tests for coronary artery disease? Is it a first line test? Or should other tests be done before it?
64 slice CT Angiogram
64 slice CT Angiogram
of coronary artery

Dr. Min: That's a good question. I think its greatest role is in symptomatic patients of low intermediate to intermediate risk. Patients without known coronary disease who present with certain chest symptoms can be first evaluated very effectively with coronary CT angiography (CCTA).

I think its greatest use at the present time -- I think it will change, it's a work in progress -- but I think that its greatest use today is in the exclusion of significant coronary disease in patients who don't have any and they then don't need any further testing.

Q: What are the implications of that for patients?
Dr. Min: When patients come to my office and complain of chest pain, they want to know whether they have coronary disease or not. And they want to know whether or not they have severe enough coronary disease that treatment mandates medical therapy or more invasive therapy. Ultimately they want to know how they're going to do, based on that treatment.

The historical tests that we have identify coronary atherosclerosis at a much later stage. Oftentimes the normal functional stress tests are not able to say that somebody is free of coronary artery disease, so to be able to give a person either an exclusion or a diagnosis of coronary artery disease (CAD) is the first step in the process.

The second question is what to do with the finding of that test. If you have non-obstructive mild CAD in a symptomatic patient with other risk factors, then medical treatment is probably warranted. In the patient with obstructive CAD, that's going to be at the discretion of who is treating that person. An argument could be made that direct referral to angiography with percutaneous intervention of an obstructive lesion for symptom benefit is beneficial, or one could argue that were it not surgical disease (i.e. left main, three vessel or proximal LAD disease) that initial medical management could be warranted with downstream cross-over if symptoms couldn't be controlled with medical therapy.

Q: One of the criticisms is that there is an overuse of CCTA.
Dr. Min: I don't think it is overused. If you compare its use to that of the nuclear imaging stress test, it pales in comparison. So it is not yet over-used. Does it have the potential to be overused? I suppose anything has the potential to be overused. I think the goal is to try to find appropriate indications for its use in clinical practice that benefits patients. I think that appropriateness criteria have gone a far way to help delineate for which indications CCTA may be most useful. I think that the soon-to-be-released consensus guidelines on coronary CT angiograms are going to help. I think that the awareness in the field is that diagnostic tests should achieve a certain sense of clinical and cost efficiency. That's an admirable goal. In that vein, I think that governing bodies, the ACC in particular, have championed this idea of appropriateness, as it relates to the implementation and efficiency.

Q: Patients write into our Forum that they are being sent to have an invasive catheterization because of an abnormal stress test. Is this a typical scenario?
Dr. Min: It's not an infrequent clinical scenario. Probably as a result of being a tertiary referral lab, we see a fair number of patients after nuclear stress testing and we can sort of debate where CT should fit: should it fit before, as a first line test, or after, as an arbiter to nuclear stress testing? We see not a trivial amount of patients, who come to us after having an abnormal stress test. CT is good at arbitrating those abnormalities. If there are artifacts or if it’s an equivocal stress test or it's a normal stress test with persistent symptoms, CT is pretty good at arbitrating those.

Q: NCDR data shows that over 1/3 of invasive angiograms done in the cath lab show no significant disease. Could those patients have avoided the cath lab if they had gotten a CT angiogram instead?
Dr. Min: Probably. Because we know that CT's negative predictive value approaches 100% -- so you literally exclude significant coronary artery disease with a 99% certainty. There was a study that looked at that out of Chicago, where they took patients with moderately abnormal stress tests and used CT to arbiter that. And if that person had severe coronary disease in the area of interest of the nuclear scan then they proceeded to angiography, but otherwise were managed medically -- and there was an 80% reduction in catheterizations!
    Catheterization Laboratory

So it's not like a trivial amount. I think we could probably achieve more than 30%. But that goes to the question of where CT is most useful. People have proposed it as a first line agent for the evaluation of patients with chest pain. Other people have said, well maybe it can be used as a gatekeeper to the cath lab. And other folks have said, well maybe it's a gatekeeper to nuclear. I think if it's used as a primary test in patients without known coronary disease who present with symptoms that are consistent with angina pectoris, that it can probably be used as a first-line agent. And by being used as a first-line imaging modality, thereby also serve as a gatekeeper to both nuclear and to cath.

Q: To reduce the use of cath and nuclear and also be cost-effective?
Dr. Min: I think so. Everything that we know this far is that CCTA is cost-saving. From single center studies to decision analytic models to large multi-center albeit retrospective studies, we have a fair amount of data to suggest that it is cost-saving and we have absolutely no data to suggest that it is going to promote more unnecessary testing or cost. I think everything that we have thus far, until we are proven wrong, is that it is potentially cost-savings.

I understand people's concern that it could potentially be used in a way that does not help the patient. Just to take a look at the coronaries for the sake of taking a look at them is I think a poor idea. But I don't think that anyone in the field is advocating that. For its use in the evaluation of symptomatic individuals we know that it diagnoses more accurately and excludes coronary disease more accurately than any other noninvasive test we have. We know that it has the ability to both exclude and identify obstructive or severe coronary artery disease, thereby presupposing that we can identify patients who can be stratified into a medical arm vs. an invasive arm. We know that it prognosticates events, and we know that the warranty period of a normal scan is long. There’s emerging data to suggest that it's at least 5 years long – that, if you have a normal CT angiogram, you're free for heart events for a good 5 years, which is longer than other non-invasive tests we have.

To say to somebody, "You have totally normal coronary arteries, but we’re going to do some more testing on you” sort of flies in the face of common sense. I guess I don’t really understand where people are getting the idea that it's cost-increasing or test-generating, because I don't think we have that data. I think we have data to suggest the opposite.

Q: Some cardiologists I've spoken with, like Ralph Brindis of the NCDR, expressed concerns that CT angiography will lead to more interventions because you'll see a blockage and even though it might be flow-limiting, it might get more people into the cath lab who maybe should be managed in other ways.
Dr. Min: That's probably not the majority. If you take the low intermediate to intermediate risk patient population, the majority of them don’t have significant coronary disease. So that’s a patient population you're sparing from cath. And in the minority of patients who have obstructive coronary artery disease, what we know is that CT is more effective at identifying obstructive coronary stenosis than stress testing. And I think that's to be expected -- CT is an angiogram and cath is an angiogram, so you'd expect that an angiogram and an angiogram would correlate better than an angiogram to a non-angiogram. If somebody presents with an 80% stenosis and chest pain and you identify that with CT, and they progress to the cath lab, where they're confirmed with an 80% stenosis, still with chest pain, then by conditional probability, if you have a negative stress test, then that stress test should be a false negative. That's just base theorem. So I don’t see how the stress test helps you in that regard.

Q: Patients write into our Forum, "I had a nuclear stress test and it showed blockages.” They use the terminology that "the stress test shows blockages". As you are saying, it is not an angiogram. Can you briefly explain to the lay population reading this, why a nuclear stress test is not an angiogram.
Dr. Min: Sure, that's a great point. What the nuclear stress test looks at is the relative perfusion of the heart, so it's all based on the fact that if one area of the heart is not getting as much blood supply, then you will see that. But it is a test that is designed to look at heart muscle, not heart arteries. And it's the blockages of the heart arteries that can potentially decrease blood supply to the heart muscle.

Nuclear Thallium Scan
Nuclear Thallium Scan

So when you see an abnormal stress test what you see is an indirect piece of evidence that you may have heart artery blockages that are compromising blood flow to that area of the heart muscle. We do stress tests for the diagnosis of obstructive coronary artery disease indirectly and for the prognostication of future events to help us re-stratify and reclassify risk. An abnormal stress test may or may not represent a blockage in the heart artery, but the goal of the stress test is to try to indirectly identify that blockage.

The CT on the other hand is just a direct picture of the artery and we can just directly look into the arteries and see whether there are blockages or not. That said, you don't get accompanying information from the CT about the heart muscle blood supply -- whether or not the blockage is causing decreased blood supply to the heart muscle.

Q: So the role for nuclear stress testing might be to see whether or not the blockage shown by a CCTA might be causing a problem.
Dr. Min: Yes. I think that's people's concern, that if we're going to do a test just to have to do another test, is that a problem? I think it's a problem if you have to do a second test 100% of the time. I think it's not a problem if you have to do a second test 7% of the time. And, at least from our lab, that's what I see. We obviously have a selected patient population that either comes in before or after the stress test but I would say the number of times that I don't know exactly what to do with the patient, i.e. whether or not the patient should go to the cath lab or go home on medical therapy and may benefit from a functional imaging test is probably on the order of 5-10%: a low number, not a high number.

Q: Another issue people are concerned about is radiation dose with cardiac CT.
Dr. Min: That's a legitimate concern, but maybe one that is representing or examining data that might be a generation or half-a-generation old. There are numerous radiation reduction algorithms that can substantially reduce radiation dose associated with CT and, without getting into comparative details, CT certainly can be effectively implemented with trivial radiation doses in comparison to say nuclear stress tests. In our lab we use ECG dose modulation, we use auto modulation of mA and we use prospective axial triggering in order to get radiation doses that are really on par with background radiation doses from walking around NYC for a year. So I guess the dogma is that average baseline radiation exposure from just living at sea-level is approximately 3 millisieverts and that's approximately the doses that we generate per coronary CT angiogram.

Is there an incremental risk of developing future fatal cancers from ionizing medical radiation? I don't know but at least theoretically I think there is. So it's responsible to practice under that thought, because it ensures that medical practitioners reduce radiation doses as much as possible. And that should be the goal. But when a patient comes in, a 60-year-old man with chest pain, I think then you need to weigh out the risks and benefits of an imaging test that includes ionizing radiation and if the risk of future cancer is 1 in a 1000, and the risk of future death from heart disease is 1 in 2 then I think that you probably have your answer.

Q: Tell me more about these dose-reducing algorithms? Where did these come from?
Dr. Min: I think you really have to tip your hat to the manufacturers. They really made the technology such that we can do this. I think the field should be applauded; particularly some in the field who've examined the issues of radiation carefully. This technology has been put forth by the industry, which was very cognizant of reducing radiation to as low as possibly achievable.

Q: You are a member of the Board of SCCT. The organization was mentioned in the New York Times article that criticized CT.
Dr. Min: The SCCT was unfairly characterized in the article. They claimed that SCCT was an organization whose only aim was to promote CT angiogram use, and nothing could be further from the truth. You have to go to the web site to see what the mission of the SCCT is.

What we have now is a new test. I don't think it's going to be the only test, but it's a new test and it's a darn good one and it’s new in our armamentarium of non-invasive testing. I think the SCCT's role is to promote the responsible use of it; to promote education of how to do it properly and with expertise; and to promote the research endeavors that demonstrate the specific clinical scenarios where CT can be most useful.

    Society of Cardiovascular Computed Tomography
Society for Cardiovascular
Computed Tomography (SCCT)

Q: How do patients know that they are getting the right coronary CT angiogram from the right place?
Dr. Min: I think they can ask about the interpreting imagers' level of training -- and not only the number of coronary CT angiograms that have been interpreted, but also where and by whom. I think that training is probably the most important thing. There is certainly a list of educational opportunities on the SCCT web site and the vast majority of folks who are SCCT-endorsed are excellent. So to have had proper training is important.

Q: Can you sum up the current status of cardiac CT?
Dr. Min: I think we're fighting against a few things. We're fighting against a new era in imaging, which is being held to a higher standard than prior imaging techniques have been held. We’re also fighting against a process, where folks have a nuclear camera in their offices and it's been a paradigm by which they have evaluated patients with coronary disease for 20 years and it's tough to reverse that. So there are multiple things that are ongoing that make this a difficult battle: to try to get everybody to see the worth of CT. But we've got a great test and now we just need to prove it to people.

This interview was conducted in August 2008 by Burt Cohen of Angioplasty.Org.