Take A Trip Down a Normal Right Coronary Artery

... courtesy of some cool video reconstruction:

UsefulProgress, a Paris-based startup, uses NVIDIA GPUs and CUDA technology to create stunningly detailed 3D stereo visuals like these from image sources such as X-ray, CRT and MRI.

-Wes

Health Care Cut Backs

... are affecting everyone:

"Doctors are noticing the trend as patients skip or defer treatments because of the troubled economy.

Many decline procedures even when they have medical insurance, doctors said, because the procedures are so expensive they can't afford the out-of-pocket costs. For a colonoscopy, a stress test, an MRI or a CT scan, the patient's co-pay can run to hundreds of dollars."

It was interesting to note that the article quoted a local "recently retired" internist. The untold story within this story is that hospital systems are equally strained as procedural revenues dwindle, placing increased pressure on their physician workforces to "produce."

-Wes

More Alphabet Soup

"ACC/AHA/ACR/ASE/ASNC/HRS/NASCI/RSNA/SAIP/SCAI/SCCT/SCMR/SIR 2008 Key Data Elements and Definitions for Cardiac Imaging"

I could not make those initials up. This was the title of the recently published paper in the Journal of the American College of Cardiology from the writing committee organized to develop clinical data standards for cardiac imaging.

Translation:
ACC = American College of Cardiology
AHA = American Heart Association
ACR = American College of Radiology
ASE = American Society of Echocardiography
ASNC = American Society of Nuclear Cardiology
HRS = Heart Rhythm Society
NASCI = North American Society for Cardiovascular Imaging
RSNA = Radiological Society of North America
SAIP = Society for Atherosclerosis Imaging and Prevention
SCAI = Society for Cardiovascular Angiography and Interventions
SCCT = Society of Cardiovascular Computed Tomography
SCMR = Society for Cardiovascular Magnetic Resonance
SIR = Society of Intervential Radiology

Wow, that's a tour-de-force of cardiac imaging specialists.* These are smart men and women who understand how the Medicare payment game is paid played. They understand that data, lots and lots of data, in fact, so much data that your head will spin, is the way to assure Medicare payment. In short: gather lots and lots of data, any way you can, to assure the folks on the Hill that you are really serious about showing the cost effectiveness of all of this testing:

The ACC and AHA recognize the importance of the use of clinical data standards for patient management, to assess outcomes, and conduct research, and the importance of defining the processes and outcomes of clinical care, whether in randomized trials, observational studies, registries, or quality improvement initiatives. Hence, clinical data standards strive to define and standardize data relevant to clinical topics in cardiology, with the primary goal of assisting data collection by providing a platform of data elements and definitions applicable to various conditions. Broad agreement on a common vocabulary with reliable definitions used by all is vital to pool and/or compare data across studies and assess the applicability of research to clinical practice. The growing adoption of electronic medical records renders an even more imperative and urgent need for such definitions and standards. Therefore, the ACC and AHA have undertaken the task of defining and disseminating clinical data standards—sets of standardized data elements and corresponding definitions to collect data relevant to cardiovascular conditions. The ultimate purpose of clinical data standards is to contribute to the infrastructure necessary for accomplishing the ACC/AHA’s mission of fostering optimal cardiovascular care and disease prevention.

On the surface, these efforts seem like the best way to begin to get a handle on the cost-effectiveness of cardiac testing. No doubt the shear volume of data generated will be heretofore unmatched and a rich source of research grants for academe for years to come.

But tied to each of these data element sets created for every cardiac imaging test, is the requirement to include as an "administrative" data element the patient's insurance information. The writing group explains this data-element necessity as a means to "foster optimal cardiovascular care and disease prevention" because:

The insurance payer element was included to be certain that patients of all payer status were included in studies equitably, especially those funded federally (ed: emphasis mine). The inclusion of this data was not to in any way suggest that cardiac imaging patients should be screened on the basis of ability to pay.

Yep, it's all to justify to the Medicare National Bank that, yes sir, we really DID need this test. While the test might be ordered irrespective of the ability of the patient to pay as the writing committee suggests, for the first time we will be granting insurers direct automated line-item access to clinical information and the test results. The implications of this are concerning.

Imagine, line item data on your renal function, ejection fraction, stress test results, cardiac risk factor analysis - all instantly available to an insurance company's computer database and conveniently entered unwittingly by the echocardiography clerical staff in the hospital of your choice. Imagine the next time you then go to purchase insurance. Best of luck to you.

Or imagine you are a doctor without an electronic medical record and ordering system - best of luck to you as you complete the test-request form that will soon look more formidable than the MCAT bubble answer sheet used to qualify for medical school. Remember to use a number 2 pencil.

Or consider if a clerical error is made during data entry: what recourse will you have? Will you have the option of editing the data entered to assure insurer payment for the test they claim was not appropriate because four data fields were left blank? "Sorry Mr. Jones, on the basis of a creatinine of 1.6, and four empty data fields on the ordering questionnaire, this test should not have been ordered, so * b-o-o-i-i-n-n-g-g *, we're not going to pay for that test after all."

But in this era of "evidenced-based medicine," these convoluted, complicated, and thoughtfully-produced-but-arbitrary data forms (Note: 20 pages were devoted in the article just for the medical history fields alone. And what is an "equivocal" test anyway?) are being feverishly developed by these cardiac imaging societies. They must justify continued testing and Medicare payments on the basis of a promise of future as-yet-undeveloped studies based on retrospective utilization data completed by the non-medical clerks at the time of test ordering. And thanks to hoards of well-meaning academics that are eager to secure more grant funding, this same dubious retrospective data will soon serve as paradigms upon which our treatment and further testing "guidelines" will be based.

But retrospective data collection like this is far easier and less expensive to gather rather than a prospective, randomized trial. Who needs those?

Heck, I guess I should stop complaining.

After all, I am a cardiologist.

-Wes

* The conflicts of interest of the authors of this document warrant notice. They are not insignificant - so much so that the article reviewers conflicts were also disclosed as an appendix to reassure a more "non-biased" critical review of paper occurred.

Reference:

"ACC/AHA/ACR/ASE/ASNC/HRS/NASCI/RSNA/SAIP/SCAI/SCCT/SCMR/SIR 2008 Key Data Elements and Definitions for Cardiac Imaging." J Am Coll Cardiol, 2009; 53:91-124, doi:10.1016/j.jacc.2008.09.006 (Published online 8 December 2008).

Regarding Cardiac CT Angiography: Which Is It?

Here. You decide.

-Wes

An Even Bigger, Better CT Scanner?

Toshiba's Aquilion ONE with some bold assertions:

"LIVES will be saved, hospital admissions slashed and heart patients diagnosed more quickly with a powerful new scanner that has put Melbourne on the medical map.

The $3.5 million machine, unveiled at Monash Medical Centre yesterday, is the most advanced model in the world and five times more powerful than conventional scanners."

Never mind that there's no data regarding these claims for this new CT scanner, the radiation received, or the real costs in terms of false positives admitted or direct costs to patients. Certainly, overtesting is creating a huge financial burden on American healthcare. How much will this new technology add to our medical device arms race in cardiology?

But the technology is interesting and demonstrates how fast imaging technology leapfrogs payers' ability to know how to pay for it:

For the first time, physicians can see not only a three-dimensional depiction of an organ, but also the organ's blood flow and dynamic function. Unlike any other CT system, the Aquilion ONE can scan one organ — including heart, brain and others — in one rotation because it covers up to 16 cm of anatomy using 320 ultra high resolution 0.5mm detector elements.

So rest assured, it will all be good. Real good.

Trust me.

-Wes

Cardiology Unplugged

I spent some time with my brother-in-law and his family today apple picking with the kids. It was a beautiful day, but a bit warmer than I had anticipated for this time of year. After dropping off way-too-many apples in the car, we walked back to meet the group in the shade of a large barn nearby. On our way back, he shared a secret with me:

"Well, I broke down."

"With what?"

"I got one of those heart scans."

"Really? Let me guess, your score was zero, right?"

"Yeah. But I was so relieved, I celebrated by having a bunch of sausage in biscuits and gravy. And you know what else?"

"What?"

"That Lipitor's good stuff."

-Wes

More Light on the Pacemaker/CT Scanner Interaction

St. Jude Medical came forth with a "Dear Doctor" letter (pdf) today regarding their findings regarding pacemaker and CT scanner interactions which represents the most specific recommendations with CT scanners and their devices to date:

Testing has shown that for devices which incorporate an accelerometor for rate responsive activity-based pacing, if the activity sensor is programmed "on" while continuous diagnostic X-ray exposure (e.g. CT scanning) is performed, if the beam of energy is directly over the implanted device, there may be a temporary increase in pacing rate during the exposure. The pacing rate will return to baseline pacing after the X-ray exposure is terminated. If increased rates occur, the pacing rate will be limited to the programmable Maximum Sensor Rate which is generally determined by the patient's physician as the safe maximum rate to be achieved during exercise. To prevent any potential transient rate increase, the clinician may want to consider programming the rate responsive sensor to Passive or OFF, if appropriate, prior to the X-ray procedure and then reprogram the parameter as desired after the diagnostic imaging is completed.

Read the rest for the details.

Medtronic's statement regarding the same issue is included here (pdf).

I cannot recall ever seeing an interaction like the one they're describing, but the implications are that we'll have to be more cautious as CT scanners become more powerful, especially as patients have chest CT's that might scan the pacemaker implant sight. For the great majority of patients, I just do not see this as a "biggie" for patient care. Anyone else with thoughts?

-Wes

Revisiting Cardiac CT Angiograms

The New York Times published an extensive article on the CT angiogram (CTA) for the diagnosis of coronary disease and is a very worthwhile read. In the report, they describe the controversy between cardiologists surrounding these tests. But in their push to provide eye-catching content, they permitted a CT angiogram proponent, Dr. Harvey Hecht of The Lenox Hill Heart and Vascular Institute of New York, to show perfect 3D images of a normal CTA obtained in nice, slow, regular heart rhythm that peels away the rib structures and shows some of the coronary arteries, the inside surface of the heart, and heart valves as he narrates the video. It's like watching something from the "Undersea World of Jacque Cousteau." Yes, they are beautiful pictures and demonstrate the incredible capabilities of this technology. Gosh, who wouldn't want those beautiful pictures of their heart?

Thank you, NYT, for giving Dr. Hecht, and the entire CT proponents all they need to peddle their scans, after all, a picture is worth a thousand words, right?

But if you read the article carefully, those beautiful pictures come at a price: both for the patient and our economically-burdened healthcare system. Not only are they fairly expensive, but the risks of radiation to the patient are real. To the authors' credit, they made this point. But they also failed to explain that for women with generally smaller frames and greater levels of breast tissue, those risks of radiation are amplified. They also didn't show a flawed CTA in their online article sidebar: like one taken in atrial fibrillation (an irregular heart rhythm) or with lots of skipped heart beats - you see, those images aren't quite so clear. Because the heart is a moving organ, collection of the images must be precisely gated to the heart beat. In people with irregular heart rhythms, motion artifact is introduced, degrading the quality of the images obtained.

The authors also failed to show the images of a patient with a heavy coronary calcium score. Those CTA images sometimes don't turn out so well, either. All CT angiograms use iodinated contrast material injected rapidly through an intravenous line placed in the arm. Scanning begins a few seconds later, after the operators think the dye has reached the patient's coronary arteries (the circulation time is estimated). Once the contrast agent reaches the arteries, it causes the blood vessels and chambers of the heart to "stand out" from the surrounding walls of the heart and blood vessels. In the case of someone with too much calcium in the arteries, the native calcium also "stands out" and might shadow the actual ability of the contrast to define the lumen of the blood vessel. Also, things like stents, which are metallic, interfere the same way. Additionally, the contrast agents used might be harmful to a patient if they have compromised kidney function, so most people have a blood test to evaluate their kidney function before the test (yes, more money).

Certainly in complex congenital heart disease, here are few tests better than CTA to define to course of anomalous blood vessels. CTA has also been invaluable to electrophysiologists to image the left atrium and the pulmonary arteries to define the size, number, and orientation of vessels before left atrial catheter ablation procedures. Likewise, there might be a role to perform CTA to exclude coronary artery disease in the chest pain patient who presents to the Emergency Room. But as a screening test for the general population or even our "walking well" in the cardiology clinic, these scans have no role today, despite what others may suggest.

Despite this, the patient testimonial was telling:

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.

"If it's free, it's for me," right?

Boo rah.

But adding up this patient's cumulative radiation dose (10 mSV for the "Calcium Score" + 27.3 mSv for the thallium study + another 21.4 mSv for the CTA) gives him the equivalent of almost 3000 chest x-rays worth of radiation.

And then his cardiologist (Dr. Hecht) wanted to repeat the test every year "so he could see how quickly the plaque in Mr. Franks’s arteries was thickening" claiming "how do we know that our therapy is effective?"

Boo rah.

For the record, I know of no study demonstrating the safety, cost effectiveness, or the ability of CTA to document CAD progression year to year. Further, Hecht's own paper demonstrated that even with extensive cholesterol lowering, no change to plaque burden was documented. I also have never seen such documentation be able to predict a cardiac event of any type. But Dr. Hecht seems to feel insults to those questioning the utility of CTA are appropriate:

Cardiologists like Dr. Brindis (and Dr. Wes, it seems) hurt their patients by being overly conservative and setting unrealistic standards for the use of new technology, Dr. Hecht said.

“It’s incumbent on the community to dispense with the need for evidence-based medicine,” he said. “Thousands of people are dying unnecessarily.”

Hmmm. Dispense with need for evidenced-based medicine? I wonder what Dr. Hecht will say to his patient when the CTA scan shows a tumor mass one year.

-Wes

References: Nico R. Mollet, Filippo Cademartiri, Carlos A.G. van Mieghem, Giuseppe Runza, Eugène P. McFadden, Timo Baks, Patrick W. Serruys, Gabriel P. Krestin and Pim J. de Feyter. "High-Resolution Spiral Computed Tomography Coronary Arteriography in Patients Referred for Diagnostic Conventional Coronary Angiography." Circulation 2005; 112: 2318-2323.

Abelson R, "Heart Scans Still Covered my Medicare." New York Times 13 March 2008.

Addendum 29Jun2008 @ 1523: - the opposing view over at "The Voice in the Ear".

More Fear-Based Medical Marketing

I'm not sure it gets better than this:

Scanning the heart's arteries for calcium deposits accurately predicts the overall death risk for American adults, a new study suggests.

"So far, this is the best predictor we have of who will have a problem and who will not," said study co-researcher Dr. Matthew Budoff, associate professor of medicine at the Harbor-UCLA Medical Center.

He and his colleagues reported the finding in the July 1 issue of the Journal of the American College of Cardiology.

A calcium scan looks for calcification, a hardening of the arteries caused by high blood fats and calcium deposits that can eventually block blood vessels, causing heart attacks, strokes and other major problems.

I can hear it now:

"Hey Marge, hey lookie here in the Washington Post! I wanna get one of dem der fancy schmancy CT scanner gizmos to find out if I'm gonna DIE sooner than you are! Let's take $600 bucks for that fancy schmancy thing-a-ma-bob out of our retirement fund. It'd be WORTH IT!"

Sometime later, in the doctor's office...

Doctor: "Well, Mr. Jones, I see my this fancy schmancy CT scan that you'd got some calcium in your coronaries. Hmmmm. And you calcium score is 210, just like Tim Russert! So, guess what?"

Mr. Jones: "What?"

Doctor: "Well Mr. Jones, you're at increased risk of DYING!"

Mr. Jones: "Uh, what do you mean, Doctor?"

Doctor: "You heard me: you're at increased risk of DYING with all that calcium in those coronaries - you know - BAM! Just like Tim Russert."

Mr. Jones: "Any idea when, Doctor?"

(Silence)

Mr Jones: "Doctor, did you hear me? When will I die? I mean, won't we all die sometime?"

Doctor: "Heck, Mr. Jones, I don't know! But I can assure you that based on this fine article here in the prestigious Journal of the American College of Cardiology (you know, the same one that's also promoting their new Cardiovascular Imaging journal) that you're gonna die of SOMETHING sooner than some of the other people who don't have that evil calcium in their arteries."

Mr. Jones: "Gosh. So what should I DO about it, Doctor?"

Doctor: "Well, you know, since we're proposing that it's a RISK FACTOR for DYING, you should do the usual stuff: eat right, take tons of statin drugs, don't smoke, take your aspirin, lose weight, eat a low trans fat, high antioxidant, super-radical-consuming diet, do yoga, take mega vitamins, face East, say a few 'Hail Mary's..."

Mr. Jones: "Uh, but I was already doing that stuff..."

Doctor: "Have you had your CRP level and genes tested yet?"

Mr. Jones: "How would that help?"

Doctor: "Well, Mr. Jones, it might mean your risk of DEATH is EVEN GREATER!"

Mr. Jones: "But what can I do about it if it's positive also?"

Doctor: "Well, you know, the usual stuff... like I said... eat right, take tons of..."

Mr. Jones: "That's okay, Doctor. I've had enough. Thanks for all of your help. Hope that $300 bucks comes in handy. Don't mind me: I'll keep doing what I've been doing and get started preparing my Bucket List. Oh, but one more thing..."

Doctor: "What's that Mr. Jones?"

Mr. Jones: "You wouldn't happen to work with General Electric like those two guys who wrote that article you quoted, would you?"

-Wes

Imaging Turf Wars

Well the inaugural issue of JACC Cardiovascular Imaging was just come out and heralds cardiologists as cardiovascular imaging experts. Eugene Braunwald's welcome letter was telling:

"Despite its great advantages, selective angiography is an invasive technique that may be uncomfortable, entails some minimal risk to the patient, and is expensive. It can be applied only a limited number of times in each patient and it is not suitable for screening. Therefore, physicians caring for patients with known or suspected heart disease yearned for noninvasive cardiac imaging. Fortunately, 2 new techniques—echocardiography and nuclear imaging—became available in the 1960s and have improved progressively since then. Literally tens of millions of these examinations are performed each year, transforming medical practice. In the 1980s, 3 new noninvasive imaging techniques—computed tomography (CT), cardiac magnetic resonance (CMR) imaging, and positron emission tomography (PET, a nuclear technique)—emerged. Each of these provides information on cardiac structure and function that is an order of magnitude greater than the earlier imaging techniques.

None of the aforementioned techniques are static and all are undergoing progressive refinement. Many important advances have been made by subspecialists in a single technique such as echocardiographers, nuclear cardiologists, and specialists in CT, CMR, or PET imaging, respectively. Each of these imaging modalities have their individual training programs, and the advances in these fields are described in specialized journals, each devoted to a single technique. Although this approach has been responsible for spectacular advances in each modality, it has led to fragmentation of patient evaluation, at times to competition between individual modalities, and to increased costs at a time of diminishing resources to pay for health care.

There is a growing consensus that the time has come to consider cardiovascular imaging in a more comprehensive, unified manner. We need a new generation of cardiac imagers who are expert with the entire portfolio of modalities and who can provide a nonbiased selection of the technique that can best solve the clinical or research problem at hand. To develop these broadly-based experts, we need new unified training programs that break down what are sometimes artificial interdepartmental and intradepartmental barriers.

Another important tool in shifting the imaging paradigm is to develop a journal of cardiovascular imaging. The Publications Committee of the American College of Cardiology and its talented staff, working closely with the College leadership, developed a vision for and then the concrete plans for the creation of JACC: Cardiovascular Imaging. The committee and its consultants selected the Editor-in-Chief, Dr. Jagat Narula, from a group of distinguished cardiac imagers. Dr. Narula has put together an outstanding group of associate editors, editorial board members, and consultants. They now deserve the cooperation of the entire cardiovascular community as they proceed on their important mission."

Radiologists are none too happy, I'm sure. No doubt they might take issue with the claim of "We need a new generation of cardiac imagers who are expert with the entire portfolio of modalities and who can provide a nonbiased selection of the technique that can best solve the clinical or research problem at hand." The friendly collaboration between radiologists and cardiologists went out the window long ago.

Why?

It's all about the money.

-Wes

CT Scan as Good as V/Q for Pulmonary Embolus

An important trial will appears in the Journal of the American Medical Association (JAMA) of a prospective randomized trial comparing CT pulmonary angiography (CTPA) to V/Q (ventillation/perfusion) scans to exclude pulmonary embolus. CT scans were not found to be inferior to V/Q scans at detecting pulmonary emboli and were actually found to be more sensitive at detecting emboli. The authors concluded that further research would be required to determine whether all pulmonary emboli detected by CTPA should be managed with anticoagulant therapy.

Given the speed and convenience of CT scanners coupled with avoidance of receiving "indeterminant" V/Q scan results, CT scans are likely to preempt V/Q scans in the diagnosis of pulmonary embolus in many patients (with the exception of patients with renal insufficiency in whom iodinated contrast agents might prove dangerous).

-Wes

CT Scanning - The Doctor's Perspective

White Coat Rants challenges the lead authors of the recent New England Journal of Medicine article to walk in his shoes when deciding when to use a CT scan for diagnosis. He describes the "no-win" situation that ensnares physicians when fear-mongering pieces appear in our medical journals and are distributed at the speed of light to news agencies.

While risks with excessive radiation exposure are very real with CT scans (and rarely mentioned in promotional materials by the manufacturers), there are risks and benefits to every test or procedure we perform as physicians.

Kudos to White Coat Rants for keeping a sane perspective.

-Wes

h/t Kevin, MD

CT Screening for Lung Cancer

“If you order a test, you’d better know what you’re going to do if it’s positive or if it’s negative.”

Truer words were never spoken by my chief resident in medical school.

So it was interesting to read this morning’s Wall Street Journal article criticizing a doctor’s perspective that CT scanning to detect early lung cancer might be dangerous when applied to the general population of at-risk smokers. People are aghast that this UCLA doctor took monies from the tobacco industry to testify in a court case about the pitfalls of such testing and applied those funds to an “educational fund” at UCLA.

In a dispute with broad implications for cancer treatment, patient advocates and congressional overseers are raising questions about the objectivity of a massive federal study that is supposed to determine whether annual CT scans of smokers' lungs can save lives.

The nine-year study, called the National Lung Screening Trial, is tracking 50,000 smokers at a cost of $200 million, and is funded by the National Cancer Institute, or NCI. Due to be finished in 2009, the study is expected to have a major impact on whether regular CT scans for smokers will become a standard of care -- and whether tobacco companies could be forced to pay for them. The 90 million current and former smokers in the U.S. are all potential candidates for such screening.

Since late last year, the Lung Cancer Alliance, a Washington, D.C., nonprofit that supports screening, has asserted in letters to the NCI and its parent, the National Institutes of Health, that two of the study's key researchers have conflicts of interest because they have accepted money from tobacco companies to be expert defense witnesses in lawsuits. The suits sought to force the companies to pay for annual CT screening.

The Alliance, which is funded by individual donations and corporate grants, including $100,000 from General Electric Co., a maker of CT scanners, also charged the study has design flaws that could bias its outcome against screening.

There are two powerful corporate interests in this debate. On one side, there is Big Tobacco, who doesn’t want to have to pay for all of these screening CT scans in smokers, and has paid a few influential doctors who understand the downside of screening tests to argue their case. On the other side, is Big Imaging Companies, backed by hospital and physician (mainly radiologists, but others too), who stand to gain handsomely with the zillions of tests soon to be performed if CT scans are better at detecting lung masses than conventional plain-film chest x-rays.

In the middle, are the patients themselves, concerned that they might get cancer because of their genetic history or social predilection to smoke. It is the patients who will receive the seemingly innocuous scans and the invasive follow-up tests required if their scan is “positive.” What we don’t know is, does it matter to the patient’s longevity?

Now I think most doctors inherently feel that CT scans can detect smaller lung nodules compared to plain chest films.

But therein lays the problem. Once a small nodule is found, what happens? People have to know: do I have cancer? And the only definitive way to determine if they have cancer is tissue. “When tumor’s the rumor, tissue’s the issue, and cancer’s the answer – sometimes.” Certainly, positron-emission-CT scans (PET scans) can be helpful, but they are not conclusive. Tissue remains the issue.

And so, a slippery slope of additional surgical interventions (needle biopsies, bronchoscopies, mediastinoscopies, or even open thoracotomies) is required to establish if a nodule is benign or malignant. Each of these procedures has risks to the patient – some of those risks include death.

So when a sensitive, but non-specific test like a CT scan is applied to a broader population of patients, we’d better accept that, in some cases, there are untoward consequences as well as beneficial ones, and it’s the patients that deserve a controlled trial with appropriate follow-up to determine which screening test is in their best interest, irrespective of the corporate forces at play.

-Wes

Update: More on the conflicts of interest on both sides of the debate can be found at the Wall Street Journal's Health Blog.

A New Hazard of CT Scanning

Being forgotten:

A cancer patient says she was left alone in a CT scanner for hours after a technician apparently forget about her, and she finally crawled out of the device, only to find herself locked in the closed clinic.

Has CT scanning become so routine that we forget that there are people involved?

-Wes

Blue Cross Illinois to Permit Reimbursement for CTA

Effective 1 September 2007, Blue Cross/Blue Shield of Illinois will permit reimbursement for CT Angiography for the following conditions:

Computed Tomography (CT) Angiography (CTA), with or without contrast enhancement or media, utilizing 64-slice or greater multi-detector row CT (MDCT) scanner, as an adjunct to other testing may be considered medically necessary for any of the following indications:

A. Detection of coronary artery disease (CAD) in:

Symptomatic individuals (such as, chest pain syndrome as described by the American College of Cardiology [ACC]) who:
Have intermediate pre-test probability of CAD (as identified by the ACC guidelines); AND
Had a non-diagnostic stress electrocardiograph (ECG or EKG) (as defined by the ACC guidelines); AND
Have a contraindication to an exercise stress test or for whom the results are equivocal or suspected to be inaccurate, OR
Symptomatic individuals with unexplained chest pain or anginal equivalent symptoms (as described by the ACC) who:
Have intermediate pre-test probability of CAD (as identified by the ACC guidelines); AND
Had no ECG changes suggestive of ischemia or infarction; AND
Had negative cardiac enzymes and cardiac marker results; AND
Have a contraindication to an exercise stress test or for whom the results are equivocal or suspected to be inaccurate.

B. Evaluation of cardiac structure and function:

To assess complex congenital heart disease, including anomalies of coronary circulation, great vessels, and cardiac chambers and valves; OR
To assess coronary arteries in individuals with new onset heart failure when ischemia is the suspected etiology and cardiac catheterization and nuclear stress test are not planned; OR
To assess a cardiac mass (suspected tumor or thrombus) in individuals with technically limited images from echocardiography, magnetic resonance imaging (MRI), or transesophageal echocardiography (TEE); OR
To assess a pericardial condition (such as, pericardial mass, constrictive pericarditis, or complications of cardiac surgery in patients) with technically limited images from echocardiography, MRI, or TEE; OR
For non-invasive coronary vein mapping prior to placement of a biventricular pacemaker; OR
For non-invasive coronary arterial mapping, including internal mammary artery prior to repeat cardiac surgical revascularization; OR
For evaluation of pulmonary vein anatomy prior to invasive radiofrequency ablation for atrial fibrillation; OR
To assess coronary arteries in asymptomatic patients scheduled for open heart surgery for valvular heart disease in lieu of invasive coronary arteriography.
Note: Refer to the Rationale in this medical policy for guidelines issued by the ACC.

MDCT with less than 64-slice scanner is considered experimental, investigational and unproven.

CTA, using MDCT, to screen asymptomatic individuals for CAD or to evaluate individuals with cardiac risk factors in lieu of cardiac evaluation and standard non-invasive cardiac testing is considered experimental, investigational and unproven.

CTA, using MDCT, for any other indication not listed above is considered experimental, investigational and unproven.

Note: For any other Electron Beam Computed Tomography (EBCT) Technology applications, such as Whole Body Scanning or Imaging for screening, see policy RAD604.006; for CT for Calcium Scoring, see policy RAD604.009.

It's a whole new world...

-Wes

Reference: Blue Cross/Blue Shield Illinois' website.

128-element CT Makes Its Debut

Some pics debut here. Total body scans in 15 seconds - but how much radiation does the patient receive?

According to the Seimen's website, when imaging just the heart:

50 %* lower dose at typical heart rates compared with today’s most dose-efficient, single source CT scanners.
5.5 msv at 80 bpm.**

Depends on system configuration. *Results may vary. Data on file.** Typical regular heart rate of 80 bpm, 12 cm scan range, male patient, small ECG-Pulsing window.

Whole body scans will be much, much more radiation...

-Wes

On Radiation Risks and What's Appropriate

Although I've commented on this before, it's good to see that others are taking notice about the potential problems with excessive use of diagnostic imaging.

But I take issue with this part of the article:

There are several steps patients can take to protect themselves, and they should not be shy about asking questions, doctors and other experts say.

“They can always inquire of the referring physician, ‘Is this test necessary?’ ” said Richard Morin, chairman of the radiology college’s quality and safety committee, adding that “exams are often done for reasons that are not quite appropriate.”

Doctors should be familiar with the radiology college index of appropriateness criteria, which rates the imaging procedures for some 200 medical conditions. Dr. Morin suggests asking the doctor ordering the test about its rating for a given condition.

Scores range from 1 to 9, he said, and “if the number turns out to be 1 or 2, you should look for some other exam.”

Whaaa? Wow, I learned something new... I now have to remember the contents of a 22-page document to see if a test is appropriate or not. I even learned there's a downloadable PDA version of the software, just to make it easy! So watch out docs, patients now might be asking you to consult your PDA while writhing in pain from an acute abdomen: "Gosh, is it acute appendicitis or a kidney stone? Let me check my handy PDA to see if I need to order this CT scan. Gee, there it is! Hot damn, he's a 9 on my handy-dandy xray scale! Okay, Wilma, take him away!"

But "appropriateness" for a test is in the eyes of the beholder. Just ask any emergency room doctor versus the obstetrician selecting a screening test for a preganant mother - each have a different take on the short- and long-term liability risks of such tests. And just for the record, I've never seen an ER doctor whip out his PDA to make such a decision about the "appropriateness" of a radiological test - especially when he's under an ever-mounting pressure to see more patients in less time while trying to never miss a diagnosis for fears of significant liability retribution.

-Wes

The Radiation Risk of CT Scanning

There is lots of buzz in the cardiology and business community about CT scanning as a means to detect coronary disease non-invasively.

Many patients with chest pain are put through a series of tests, including electrocardiograms and stress tests that are time consuming and expensive: In the U.S. alone, such testing costs $10 billion to $12 billion a year. Other patients go on to have an invasive angiography, or a cardiac catherization to look at the arteries, even though as many as 20% to 40% of these cases reveal no clinically significant narrowing of the arteries.

"Because stress tests are not perfect, there are many patients who go to cath lab who don't need it," said Harvey Hecht, chief of cardiovascular computer tomography at Lenox Hill Hospital in Manhattan. "All of those will be eliminated by doing cardiac CT."

Well, maybe not, Dr. Hecht. A relatively recent article on CT scanning from Circulation demonstrated that such high resolution scanners still could only make a diagnosis 75% of the time at best, since coronary calcium and even a single irregular heart beat could distort an acquired image. But companies want to market to the worried well, offering piece of mind that a heart scan will reassure them they are not at risk of heart disease, and turn a profit.

But what these companies also fail to mention is the radiation exposure these scans supply to the average man and woman. (Yes, ladies, women get much more radiation than men with these scans).

So, in the interest of public disclosure, I thought I'd assemble here some interesting data that I culled from various sources regarding radiation exposures and cancer risks with common diagnostic cardiovascular tests. Hopefully this will serve as a wake-up call to patients considering these tests. It should be mandatory that radiation dose be disclosed with these tests, especially as the number of x-ray elements grows from 64-slice to 128-slice scans. From the FDA's website:

The effective doses from diagnostic CT procedures are typically estimated to be in the range of 1 to 10 mSv. This range is not much less than the lowest doses of 5 to 20 mSv received by some of the Japanese survivors of the atomic bombs. These survivors, who are estimated to have experienced doses only slightly larger than those encountered in CT, have demonstrated a small but increased radiation-related excess relative risk for cancer mortality.

Radiation dose from CT procedures varies from patient to patient. A particular radiation dose will depend on the size of the body part examined, the type of procedure, and the type of CT equipment and its operation. Typical values cited for radiation dose should be considered as estimates that cannot be precisely associated with any individual patient, examination, or type of CT system. The actual dose from a procedure could be two or three times larger or smaller than the estimates. Facilities performing "screening" procedures may adjust the radiation dose used to levels less (by factors such as 1/2 to 1/5 for so called "low dose CT scans") than those typically used for diagnostic CT procedures. However, no comprehensive data is available to permit estimation of the extent of this practice and reducing the dose can have an adverse impact on the image quality produced. Such reduced image quality may be acceptable in certain imaging applications.

The quantity most relevant for assessing the risk of cancer detriment from a CT procedure is the "effective dose" . Effective dose is evaluated in units of millisieverts (abbreviated mSv; 1 mSv = 1 mGy in the case of x rays.) Using the concept of effective dose allows comparison of the risk estimates associated with partial or whole-body radiation exposures. This quantity also incorporates the different radiation sensitivities of the various organs in the body.

So to update the FDA's table, I added a few lines regarding average radiation doses of current cardiovascular tests for comparison:

Radiation Dose Comparison

Diagnostic Procedure	Typical Effective Dose (mSv)	Number of Chest X rays (PA film) for Equivalent Effective Dose	Time Period for Equivalent Effective Dose from Natural Background Radiation
Chest x ray (PA film)	0.02	1	2.4 days
Mammogram	0.13	6.5	15.8 days
CT head	2.0	100	243 days
CT abdomen	10.0	500	3.3 years
Coronary Angiogram	3.4	170	1.1 years
64-slice CT (male)	15.2	760	5.1 years
64-slice CT (females)	21.4	1070	7.1 years
Dual-isotope (3.0mCi Tl-201+30mCi Tc-99) Thallium scan	27.3	1365	9.1 years
128-slice CT	???	???	???

So think about this when you get your next CT scan "just to find out" your coronary disease risk: is it worth the radiation exposure?

-Wes

12:21 PM CST: Data for mammogram and dual-isotope Thallium test added. Reference: Thompson RC and Cullom SJ. J Nucl Cardiol 2006; 13: 19-23.

64-Slice CT Predicts ER Outcome in Patients with Chest Pain

Today a single-center, prospective study from Israel was published that evaluated higher-resolution 64-slice multi-detector computed tomography (CT) scanning (MDCT) in patients with chest pain presenting to the Emergency Department. The study, published on-line in the journal Circulation, prospectively studied 58 patients with chest pain and no EKG or chemical evidence of cardiac injury that received MDCT scans to evaluate their coronary anatomy. 15 patients were classified as normal, 20 had mild, non-specific disease and 23 had significant coronary blockage (defined as greater than 50% occlusion) in at least one artery. The study demonstrated that MDCT had a 100% negative predictive value and 100% sensitivity (20/20) with a 92% specificity (32/38 patients) for a positive predictive value of 87% (20/23). Importantly, the study followed patients for 15 months after their ER discharge, and no deaths or heart attacks (myocardial infarctions) occurred in any of the 35 patients discharged from the Emergency Department after initial triage and MDCT. One patient had a late coronary intervention at 13 months after discharge of a distal circumflex coronary artery.

The study was limited by its relatively small size and its single-center experience. Additionally, patients with irregular heart rhythms (atrial fibrillation or frequent premature ventricular contractions) or rapid heart rate (>90 beats/min) were excluded.

Nonetheless, the potential for these scans to have a major impact on ER decision making, especially in patients with other equivocal risk factors and testing, is significant. Cost-effectiveness data are still needed, but the potential for limiting expensive cardiac admissions might be found to be cost-effective in the long run. It likely won’t be long before these scanners become standard equipment in Emergency Departments across the country – patients will demand it.

But there’s still one big barrier to implementation: we still have to secure insurance reimbursement for them… You can bet the Big Boys (like GE and Phillips) will be working on this...

-Wes

Coronary Calcium Screening by CT Scan

New guidelines by the American Heart Association and the American College of Cardiology were issued earlier this week supporting the use of coronary calcium scans to assess risk of future heart attack.

Coronary calcium scans, also known as heart scans, provide pictures of the calcium deposits in coronary arteries that might herald the existence of a significant blockage. Depending on the amount of calcium detected, the result of this test is often called a coronary calcium score. Scores range from 0 to over 1000, with the lowest numbers suggesting lower risk and higher numbers suggesting a higher risk of future heart attack. Heart scans and coronary calcium scoring may indicate if someone is at a higher risk of a heart attack or other problems well before they have any outward symptoms of disease.

The new guidelines represent a reversal of the AHA/ACC recommendations from 2000 when there were insufficient data to formalize recommendations regarding coronary artery calcium (CAC) screening to the general public.

But the new recommendations, published online 12 Jan 2007 in the online version of the Journal of the American College of Cardiology, are made with some qualifications. CAC screening is only recommended for patients at moderate risk of developing coronary artery disease while very high and low risk patients are still not recommended to have CAC screening.

So what justifies a moderate-risked individual in whom the CAC screening is recommended?

People referred for CAC screening should not have evidence of other vascular disease or be at high risk of developing such disease (like diabetics or those with known coronary artery disease). If a person has a greater than 10% risk of cardiovascular death in 10 years as determined by having two or more of the following cardiovascular risk factors: cigarette smoking, hypertension exceeding 139/89 or those being treated for hypertension, high cholesterol or low HDL (< 40 mg/dl), a family history of premature coronary heart disease (male first-degree relative < 55 years or a female first-degree relative < 65 years) and age (men >45 and women >55), then they might be candidates for screening.

You can estimate your own risk by using this special calculator from the National Heart, Lung, and Blood Institute.

People with 0 to 1 of the cardiovascular risk factors above should not undergo screening, according to the guidelines.

The controversies and limitations of this test are nicely outlined here. Realize, too, that this report does not cover the appropriateness of newer, 64-slice CT scanners for evaluation of coronary artery disease screening. (Medicare still considers these "experimental").

So look for more CT scanners to come to a mall near you - but only get it if you really need it.

-Wes