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Coronary CT Angio

Discussion in 'Cardiology' started by HomerSD, 06.29.08.

  1. HomerSD

    HomerSD

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    Nice article on the business side of coronary CT angios in the New York Times today:

    CT Angio

    I particularly enjoyed one cardiologist's impression of evidence based medicine: “It’s incumbent on the community to dispense with the need for evidence-based medicine,” he said. “Thousands of people are dying unnecessarily.”
  2. radslooking

    radslooking

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    sad. again, money clouds the minds of some of the smartest people. can you imagine a man of science saying such a silly thing? Apparently when his pockets are lined with gold, EBM is something that can be worked around.

    too many unnecessary stents....and cardiac ct's just shouldnt be done until there is evidence they work. even if somebody does have chest pain, i would think a functional study would be necessary anyhow, to document true ischemia and at least localize the territory. Would you stent an 85% occluded artery with no definite evidence it's causing functional ischemia? i don't think you should unless you have clear angina that is affecting QOL.
  3. radslooking

    radslooking

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    "After doing research on the Internet, he found Dr. Hecht, who recommended a CT angiogram. Dr. Hecht acknowledged that Mr. Franks probably did not have severe heart disease. But he said the scan would be valuable anyway because it might reassure him. And his insurance would cover the cost"

    find what's wrong with paragraph......
  4. radslooking

    radslooking

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    oh, and to make it worse...this Dr. Hecht did the study AFTER a normal stress test....AND he recommended a follow up CT one year later, despite showing only 25% occlusion of a vessel or two. The guy should have his license put on probation or taken away entirely. that's ridiculous.
  5. CCMD2005

    CCMD2005 Member

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    One thing to point out, an imaging stress test is not 100% sensitive, so if the patient has true anginal symptoms and a negative stress test, could the patient have significant obstructive disease (or even multivessel disease)? Simply put, yes. If a patient comes in like that, and the clinical scenario is suggestive of coronary disease, one should define the coronary anatomy (kind of like they did in the COURAGE trial - patients randomized after diagnostic angiogram).

    So if a patient has an 85% lesion on coronary angiogram, and there stress test is negative, but they have symptoms; would you intervene? I don't think you can flat out say NO. There are many nuances to this situation....
  6. radslooking

    radslooking

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    excellent point. that wasn't the scenario presented in the article when this nightmare of a cardiologist sent him for a cardiac CT, but your point is a good one. a good story overrides a negative stress in a likely CAD candidate.
  7. gagolden

    gagolden Call me the DOgg

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    Just think of the cost savings of coronary CT on younger people with minimal RF who go to the ER for CP. Scan em, say its less likly your heart, functional study in a couple of days but you dont need to get admitted. Insurance and pts alike would love it.

    How many CP rules out have you done in the last two years?
  8. CCMD2005

    CCMD2005 Member

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    Agreed, probably some of the best evidence for CT angiography to date is to use is in the acute setting to rule out acute coronary syndromes (this is were it has a very high >99% NPV!). This may well become the technologies most widely used application. It would be a great cost savings, but it may become a panacea for the ED, akin to CT pulmonary angios.
    -CC
  9. radslooking

    radslooking

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    that's cool, and I probably wouldn't doubt that will become a usage of the technology. But scanning people without pain with negative stresses is kind of ridiculous. Certainly without better evidence. That's just arguing yourself into more money.
  10. CCMD2005

    CCMD2005 Member

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    True, I think your point is right on. If a person does NOT have a high burden of disease on CT scan, then why do a functional study. It's kind of interesting, but there is one validated method of using CT scanning to risk stratify asymptomatic patients: EBCT (Calcium scoring), this has been found to better risk stratify patients than the Framingham score, but because its not reimbursed that well and its a relatively cheap test, it is rarely used in clinical practice....this gives credance to your arguement.
  11. grendelsdragon

    grendelsdragon Synesthetic

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    CT angio has a fundamental handicap--major causes of uninterpretable segments is coronary calcium and previous stents. Therefore CTA is less able to give adequate visualization of the coronary tree in regions where it is most necessary. If someone ends up going to cardiac cath after a non-diagnostic CTA, the patient would already have received 50-100 ml of bolus IV contrast, increasing the possibility of RIN.

    I think CTA does have its uses, such as visualization of anomalous coronary anatomy, or evaluating the IMAs in a re-op CABG. CT scanning (without contrast) is also used routinely with our PET/CT protocol primarily to calculate tissue attenuation for our nuclear imaging(the calcium Z-score is simply a bonus). But CT's niche in evaluating ACS is definitely not yet substantiated.
  12. tibor75

    tibor75 Member

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    then what was the point of the stress test?

    Good story, likely CAD, positive stress = CATH

    Good story, likely CAD, negative stress = I don't believe the stress, CATH anyway.

    Nuclear tests pay VERY WELL in private practice. they are horribly abused. Routine stresses 1 year after stent / bypass are done ALL the time, yet without symptoms, there is NO indication whatsoever.

    Given how nuclear tests and caths are abused, why would CT be any different?
  13. tibor75

    tibor75 Member

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    Given the high radiation load and the risk of future malignancy, I doubt there will be any cost savings.
  14. grendelsdragon

    grendelsdragon Synesthetic

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    That is a great point Tibor. Housestaff and fellows do not seem to consider simple Bayesian thinking into their clinical decision-making progress (as we had to in the heady days of V/Q scans and simple exercise treadmill tests). It seems many here are more impressed with technology than clinical judgment.

    CCDMD,
    For example, the work on CTAs that quoted a NPV of 97-99% for detecting 70% stenosis. The residents and medical students here should keep in mind that NPV (the probability that a negative test means no disease) depends upon prevalence of disease in the study population, which I recall was in the neighborhood of ~10%. If the prevalence of disease in your population increased to 50% or 90% (as in cardiology clinic or CCU respectively), then your NPV goes down to ~90% and ~50% respectively.

    Take for example if your diagnostic test was flipping a coin (heads=CAD, tails=clean coronaries). If the prevalence of disease in your study population was 5%, the NPV of your fancy test (the coin toss) is 95%! So, MANY diagnostic tests (such as the simple exercise-treadmill test) will perform very well in excluding disease in a population with low disease prevalence.
  15. radslooking

    radslooking

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    Douglas Ring, a 63-year-old Los Angeles real estate developer, said he received a CT heart scan in October 2005, on the advice of Dr. Ronald P. Karlsberg, a Beverly Hills cardiologist. “Ron has been my physician for 15 or 20 years, and he got this new toy in his office, and he said I should try it,” Mr. Ring said. He took the test despite having no symptoms of heart disease, like shortness of breath and chest pain. He was already taking cholesterol medicine, and a different test had shown no problems with his heart.
    The CT heart scan by Dr. Karlsberg found a moderate buildup of plaque in one of Mr. Ring’s coronary arteries. The doctor increased Mr. Ring’s cholesterol medicines and encouraged him to diet and exercise.
    Dr. Karlsberg said he considered the information from Mr. Ring’s CT scan extremely valuable. “Here’s a case of near-serious coronary disease that required medical management,” said Dr. Karlsberg, a partner at the Cardiovascular Medical Group of Southern California, which conducted about 1,400 CT heart scans last year.

    Apparently, in this instance, it was used for risk stratification. It was used as justification to increase his cholesterol medication (which already has well established guidelines), as well as to admonish the patient to diet and exercise (already should have been done). If you want to argue CT scans are being done to motivate patients...well then that's a different argument.

    Sometimes, it is not the doctor but the patient who is eager for the scan. On a recent Wednesday morning on the Upper East Side of Manhattan, Dr. Harvey Hecht at Lenox Hill Hospital watched from a lead-shielded control room as a 59-year-old patient, Robert Franks, underwent a CT angiogram.
    Mr. Franks has a family history of cardiac disease, and his father and two uncles died of heart attacks. But Mr. Franks, director of corporate security for Time Inc., is in excellent shape. He works out daily and takes two cholesterol-lowering medicines. The drugs have reduced his LDL, or bad, cholesterol to 60, a remarkably low level.
    Nonetheless, in February, Mr. Franks took a test called a calcium score, which measures the amount of calcified plaque in the arteries. The test, a less extensive form of scanning, revealed a moderate buildup of calcium in his arteries, a potential sign of heart disease.
    So he decided to have a nuclear stress test. When that test showed no problem, the cardiologist who conducted it said he did not need more testing.
    But Mr. Franks was still not satisfied. “I’m someone who wants to know,” he said.
    After doing research on the Internet, he found Dr. Hecht, who recommended a CT angiogram. Dr. Hecht acknowledged that Mr. Franks probably did not have severe heart disease. But he said the scan would be valuable anyway because it might reassure him. And his insurance would cover the cost.
    A CT scanner is 8 feet high by 8 feet wide and 2 feet deep, with a doughnut-shaped hole at its center. Wearing a hospital gown, Mr. Franks lay on a table attached to the machine and was injected with a drug to lower his heart rate, along with a contrast dye to improve the quality of the images from the test. (Mr. Franks later compared the warmth he felt after the injection of the dye to “the first sip of a well-blended martini.”)
    In the control room, Salvatore Fevola, the manager of the CT scanning equipment at Lenox Hill, instructed Mr. Franks, who was raising his hands over his head, to hold his breath as the table moved through the machine.
    Twelve seconds later, the test was complete, and the machine’s software began to assemble information from thousands of images into a single coherent picture of Mr. Franks’s heart.
    A few minutes later, Dr. Hecht studied the results. As he had expected, the angiogram revealed that Mr. Franks’s arteries were healthy. In some places, plaque had blocked 25 percent of their blood flow, but in general, cardiologists do not consider blockages clinically relevant until they reduce blood flow at least 70 percent.
    After Mr. Franks finished dressing, he joined Dr. Hecht, who went over the results, explaining that his heart appeared healthy and that he would not need a stent. Still, Dr. Hecht recommended that Mr. Franks have another CT angiogram next year to check that the plaque was not thickening. Mr. Franks agreed, pronounced himself satisfied and left.

    In this case, the cardiologist ordered a stress because he was 59? I have no idea. Apparently he ordered the coronary CT to reassure his patient. And because insurance would pay for it. Good reason.
    Last edited: 07.13.08
  16. tibor75

    tibor75 Member

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    the problem here is not the patient or the doctorb, it's the insurance company who is paying for a worthless test for no indication. And this country wonders why health care spending is as bad as it is.
  17. grendelsdragon

    grendelsdragon Synesthetic

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    The vast majority of people >=60 years of age have atherosclerosis and asymptomatic CAD, and you should figure this into your pretest probability. Therefore, in conducting any tests on patients in this age group, you are operating under the assumption that the patient already has athero, in which case the CT does not help you. Remember that coronary calcium/athero/stenosis does not cause MI or sudden death, but rather dyspnea, angina or equivalent. The cause of ACS/MI/sudden death is plaque rupture, which statistically happens more often in coronary regions WITHOUT significant stenosis (<70%). No diagnostic test as of yet can diagnose an unstable plaque.

    Cost of 1,400 CT scans: ~1.4 million.
    Additional information gained: negligible
    Price of advising regular exercise and good diet: free
    Look on our faces when health insurance premiums are raised due to spurious expensive tests: priceless.
  18. radslooking

    radslooking

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    thanks grendel, nice post :D rein in some of these guys eh? They're giving some of us a bad name!

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