Beware the "false positive" stress test

There's a widely-known (among cardiologists) problem with nuclear stress tests. It's called the "false positive." (Nuclear stress tests are known as stress Cardiolites, stress thalliums, stress Myoviews, persantine stress tests, adenosine stress tests)

Stress tests, nuclear and otherwise, are helpful for identifying areas of poor blood flow. If an area of poor blood flow is detected and the area is substantial, then there may be greater risk of heart attack and other undesirable events in the relatively near future.

What "false positive" means is a stress test that shows an abnormality but it's not true--it is falsely abnormal. There are a number of reasons why this can happen. The problem is that this phenomenon is very common. Up to 20% of nuclear stress tests are false positives.

There are indeed situations where there may an abnormality and it is not clear whether it is true or false. This may lead to a justifiable heart catheterization or CT coronary angiogram. But, given the extraordinary number of false positives, there's a lot of gray in interpreting these tests. Hospital staff, in fact, call nuclear medicine "unclear" medicine. It's common knowledge that you can often see just about anything you want to see on a nuclear image of the heart. Abnormalities in the bottom of the heart, the "inferior" wall, are especially common due to the overlap of the diaphragm with the heart muscle, yielding the appearance of reduced blood flow. Defects in the front of the heart heart are common in females with large breasts for the same reasons.

The problem: The uncertainty inherent in nuclear stress tests opens the door to the unscrupulous or lazy practitioner. Any blip, tick, or imperfection on the nuclear images serve as carte blanche to drag you into the hospital for procedures.

This abusive practice is, in my experience, shockingly common for two reasons: 1) It pays better to do heart catheterizations, and 2) Defensive medicine.

What's the disincentive? Only doing the right thing and maintaining a clear conscience. Slim reasons for many of my colleagues--and a lot less money.

If you are without symptoms and feel fine, and a nuclear stress test is advised by your doctor, followed by a discussion of an abnormality, insist on a discussion of exactly what is abnormal, just how abnormal, and what the alternatives might be. If you receive unsatisfactory or incomplete answers despite your best effort, it's time for another opinion.

Comments (11) -

  • Michelle C

    10/25/2007 4:23:00 PM |

    I was very interested to see this article.  My father had a cardiolyte test.  The results said that his arteries were clear, but that he'd had a heart attack in the anterior infraseptal wall.  He was shocked because he's never had any symptoms.  His doctor wanted to refer him for a possible angiogram, but my dad declined.  Now I wonder if this was a misdiagnosis.  It's made getting health insurance next to impossible for him, and he regrets the day he ever agreed to the test in the first place.

  • Jerry Lewis

    10/16/2008 12:04:00 PM |

    Stress management is a very important factor to improve short term memory loss. Stress causes the body to release a hormone called cortisole which blocks the memories from being registered. Since it is a known fact that all women going through early menopause have stress, it is essential to stay positive and stay stress free. http://www.xanax-effects.com/

  • Anonymous

    7/24/2009 1:02:26 AM |

    What is the incidence of false positive nuclear stress test results in women who have had previous (non-cosmetic) breast surgery for cancer and benign lesions?  I would appreciate reference to studies if any.

  • R.G.

    9/2/2009 8:40:08 PM |

    I am so glad to find this site.  I recently had the Thallium test which came back positive, yet I'm not overweight, don't smoke, have normal to low blood pressure and a resting heart rate of 60.  My risk factors are being post-Menopausal and having a family history.  I asked my MD if he would be willing to re-test and he refused, so I'm going to a different doctor, not telling him anything about my previous results and get a second, unbiased opinion.  Then if that one comes back positive, I'll know for sure what steps to take next.

  • Michelle

    10/30/2009 8:28:16 PM |

    I had an abnormal stress test and just had an angiogram today. It showed no blockages and that I have large arteries. My cardiologist says my heart is an great shape. It does put my mind at ease knowing I don't have CAD. Since my mom had her first 95% blockage at 36.


    Michelle

  • Anonymous

    11/9/2009 11:16:14 PM |

    I had a false positive stress test.  The stress test came out markedly positive, which prompted my doctor to send me to heart catheterization immediately the next day.  But the heard cath showed that my heart was completely fine.  Of course, you can imagine the stress that I went through.  Even though it is good to know that my heart is fine, I am feeling like short of breath once in a while, probably  due to lack of enough exercise as well as possible anxiety.  I wish that noone had to go through this.

  • buy jeans

    11/3/2010 4:54:37 PM |

    Buy jeans from our clothing store online!

  • Anonymous

    4/18/2011 11:29:39 PM |

    I had a false positive Nuc Stress Test last week. After research the reason was due to the following. 18 months ago I had bariatric surgery The Ruin Y, procedure and lost over 100 pounds. My BMI went from 45 to 25. Last week after eating a Beef Stick I developed chest pains radiating down my left arm and was taken to ER Via ambulance. After the stress test, I had a Cath and was found to be normal - 20% blockage in one artery. My Bariatric Surgeon said I suffered from "Dumping" which can mimic an heart attack. The abnormal Nuc Stress test was due to a overlay of tissue on the posterior part of heart from the surgery. Next time I talk with Surgeon before more tests, but they were two different cities and being 55, with a blood AIC over 10 for 10 years, was prime candidate for MI. Better safe than sorry!

  • Charlie

    12/11/2012 1:45:22 PM |

    I am a Nuclear Medicine technologist.  Several factors influence a false positive test:

    1. Motion - heavy breathing or sliding from the original position in the scan can cause a false positive.  This is generally checked by the tech after the scan is finished.  In many cases the scan will be performed again if there is over a certain amount of movement visualized in a graph.

    2. Breast size - patients with large / dense breasts or with breast implants (saline or otherwise) will definitely cause a breast attenuation artifact that looks similar to an infarction or ischemia.  The resting images typically provide a map of the heart tissue to view what possible attenuation might occur, or previous infarctions.  Generally cardiologists are able to determine the factor based on information given from the technologist, as well as location of the defect in the image.

    3. Diaphragm - the diaphragm on some patients can be very dense (patients with a large belly pushing the diaphragm up, or a thin person having an elevated hemidiaphragm that sits too closely to the cardiac emmissions.  This can cause an inferior wall defect.

    4. Coronary abnormalities - certain twists and turns can cause a much higher reduction of blood flow at the time of the test.  Not common, but I've seen it in correlation to a angiogram.  Also if you have several vessels that are equally diseased, the global perfusion will be equal and hard to discern of a specific disruption of blood flow to a particular area.

    5. Cardiologist / Radiologist reading - some cardiologists and radiologist read much different than others.  I've seen some tests that have a tiny defect, most likelly from motion or obesity that is read positive automatically without any further detail.

    -----------
    My advice is this.  I think it is a great test in conjunction with a full work up by a cardiologist you trust.   If it comes back positive, know that it's possible you are fine and need further workup.  90-95% of the tests I perform are negative, with very very rare false negatives (meaning if it's negative, it's very likely you do not have trouble with perfusion to your heart).  Most of my false positive performances come from patients that have a large BMI, large breasts, breath heavily, or cannot raise both arms.

    Keep in mind an angiogram is up to interpretation as well.  Many cardiologists treat different blockages in different areas much differently.  Some treat with medicine and others will stent areas that are borderline treatable.  

    Hope this helped a bit.  Not much in medicine is completely black and white, these tests are tools to help give the best treatments possible and they are becoming better and better everyday.

  • Jolene

    8/9/2013 9:36:49 PM |

    I have a BMI of 66! I am 368 ibs. I had a nuclear stress test done. the activity portion failed with a lower part being gray or "no flow" on the images. I DID move my legs at teh end of the test without thinking. However when i asked for a new test the family nurse Practitioner (who told me the results) refused saying it wouldnt change the facts? What facts!? I am 31, overweight. Thats it. I have NEVER smoked, done drugs, drank, my Cholesterol is a 98, my BP is usually borderline (147/74)  or low (112/72). I have no family history of anything, no one has died from heart disease or had heart disease? So again, what facts? Also she as i said is a FNP! Not the Cardiologist? So why is she even looking at my charts and giving me any kind of advice about procedures or anything? Any help understanding this would be much appreciated. Thanks.

  • KUPPUSAMY

    7/8/2014 2:43:36 AM |

    I have stress test positive in 2006 followed by Angiogram negative. Since then around 6 stress tests positive (equivocal). I am diagnosed for Rosucar ASP 10(Rosuvastatin and Asprin capsules) & Telmisartan 40 mg and amlodipine  5mg.

    I don't have any complaints but for hypo thyroid TSH 7.80.

    Now cardiologist advise to go for stress test again but this time stress test thallium. Will it identify correctly?

    What are the ill facts and side effects about Stress test Thallium

    Please advice me.

    Kuppusamy

Loading
Drug industry "Deep Throat"

Drug industry "Deep Throat"

A Heart Scan Blog reader brought the following letter from a former pharmaceutical sales representative to congress to my attention.

Interesting excerpts:

As a former drug representative for Eli Lilly, I spent 20 months increasing the market share of my company’s drugs. I was recruited fresh from college with an eager desire to employ my degree in molecular biology and biochemistry. Shortly after my hiring, it became clearly apparent that a drug sale had much more to do with establishing personal relationships than it did with understanding the latest science. However, any doubts I held regarding the effectiveness of such methods were dispelled by the results of my persuasiveness and the financial rewards I received for my efforts. The latter also helped me rationalize the many ethically dubious situations I routinely encountered in my work. Upon my departure from the industry, I began working for the public’s health. Seven years later, as a result of my experiences and education I am more convinced than ever that the goals of the pharmaceutical industry often stand in direct conflict with the practice of ethical and responsible medicine. Nothing in my recent research causes me to believe that my experiences were anything but typical of the training and practice of the majority of drug reps plying their trade today.


“There’s a big bucket of money sitting in every [doctor’s] office.” – Michael Zubillaga, Astra Zeneca Regional Sales Director, Oncology


The majority of drug reps entering the work force today are young and attractive. The ranks of reps are replete with sexual icons: former cheerleaders, ex-military, models, athletes. Of course, as a sales job, the reps must be eloquent and convincing. Depending on the population, certain ethnicities are preferred either to make the rep distinct among other reps or to provide them with a cultural advantage in connecting with their clients. Noticeably lacking among most new reps is any significant scientific understanding. My personal case illustrates this point rather vividly: In my training class for Eli Lilly's elite neuroscience division, selling two products that constituted over 50% of the company's profits at the time, none of my 21 classmates nor our two trainers had any college level scientific education. In fact, that first day of training, I taught my class and my instructors the very basic but crucial process by which two nerve cells communicate with one another. It is very likely that the majority of my class couldn't explain the difference between a neuron and a neutron prior to sales school. While it's certainly a bonus to have a scientifically educated representative, it is far from a primary recruitment criterion. Youth is a much higher criterion for the sales position.

Sales representative trainers are almost always veteran sales representatives and consequently, much of the training they offer is implicit in the anecdotes they give. This informal training parallels the standard training offered by the industry and in many ways compliments it. It is tacitly accepted by management and perceived as the "real" training by many veteran sale representatives. Among the more dubious "unofficial" lessons a new rep learns are: how to manipulate an expense report to exceed the spending limit for important clients, how to use free samples to leverage sales, how to use friendship to foster an implied "quid pro quo" relationship, the importance of sexual tension, and how to maneuver yourself to becoming a necessity to an office or clinic.

The most troubling aspect of pharmaceutical sales is systematic befriending of our clients. In addition to the psychological profiling mentioned above, drug reps are taught to constantly be on the lookout for personal effects that will help us connect to our doctors. When entering an office for the first time, we nonchalantly survey it for clues to ingratiate ourselves with our client. Similarly, conversations are intentionally steered into the realm of personal details such as religion, family, or hobbies to acquire similar information. As a matter of training, we collect this data subtly. In the course of a conversation with clients, we may glean facts about their prescribing preferences, the dates of their children’s birthdays, where they were born, or what music they enjoy. Training encourages us to commit these details to memory just long enough to return to our cars and instantly type up a “call report” listing the details of our conversation. On a daily basis, we connect our computers to a central database that uploads the information we’ve acquired, allowing us to share it with our partner drug reps and company marketers. Subsequently, drug reps interweave pieces of conversation specifically tailored to appeal to their client drawn from personal information that wasn’t necessarily shared with them. For example, Dr. Jones will be nothing but grateful when I supply him with a cake celebrating his children’s birthday when, in fact, he told my partner (and not me) the birthdates several months prior in a personal conversation.


The writer's comments ring true: The relentless attention-grab of sales representatives, using clever tactics that include access to detailed records of physician prescribing habits, big smiles and eye-winking, are detailed perfectly.

There's nothing wrong with a business doing its job by marketing its products and services. What is so wrong about this picture is that one side is so well-equipped, heavily funded, with access to extraordinary resources that the other side (physicians) don't have. And the physicians aren't the victims--YOU are.

A middle-aged, receding hairline physician, faced with a 28-year old attractive woman asking all manner of ingratiating questions but knowing full well what she is doing, having strategized for weeks on how to manipulate the behavior of her "mark," is helpless.

Like the mortgage-backed security crisis, we've reached another phenomenon of crisis proportions. Direct-to-consumer drug advertising, drugs for non-conditions and well people, pinpoint marketing of drugs to physicians--it's all gone too far.

Personally, drug representatives are not welcome in my office. This generally prompts puzzled, followed by angry, looks from the representatives, often traveling with a district supervisor hoping to help polish their pitch. If patients didn't request free samples, the reps would not step foot in the office.

Comments (16) -

  • Anonymous

    6/18/2009 1:53:18 PM |

    It sounds like doctors need salesmen/women residence training!

    I used to be a purchaser for our family company and later a large multi-national food firm and what is written here rings true with my experience too.  Most of the sales people were young ladies, that would come to my office, asking all kinds of personal questions, wanting to get to know me better, taking me to meals, concerts, sometimes just calling me up to chat.  

    You have to realize that she/he is doing their job.  And you need to realize what your job is, which in my case was doing best for the company.  I suppose fortunately for me, my father was a salesman.  I had an idea of how the sales pitch works.  

    I wish more doctors thought as you do.  As you mention, as a patient I don't buy from the drug company reps.  I purchase what the doctor recommends.  That is where the buck should stop.

  • John

    6/18/2009 1:55:01 PM |

    I know this to be true, since I know a very beautiful young RN that got out of nursing to be a pharmaceutical rep.  She later got back in to nursing, when one of her clients (a Dr. at a medical spa) made her an offer she couldn't refuse!  She didn't stay with that job even a year though.  I'm sure you guess by that she is back in the pharmaceutical business!

    She told me that in my town of about 50 doctors, that only a couple of them would allow the reps to stop in.  Most of the doctors here are like you and do not welcome the reps.

    You can always tell which doctors go for this, because they will have a room full of samples and every kind of prescription drug poster imaginable hanging thoughout the office, especially in the exam rooms!

    As a patient, I find it really annoying to see almost as many reps waiting to see the Dr. as their are patients!  

    Everyone I know assumes that the doctors who welcome the reps do get something in return, and probably more than just a birthday cake.  I'm thinking free vacations for prescribing certain drugs.  

    Could that be possible?  No one will ever talk about the "benefits" a doctor receives for welcoming in the reps, but it sure would be interesting to know.

    Thanks for he very interesting "deep throat" post!

  • Get Primal

    6/18/2009 2:14:16 PM |

    Dr. Davis,

    I enjoy your blog very much, but there are a couple issues I'd like to follow up on.  Full disclosure, I am a medical device sales rep.

    The first issue is regarding a post a couple weeks ago regarding the greed of medical device companies.  You referenced the initial price of drug eluting stents versus the prices today.  There isn't an industry in the world that doesn't price their hot new technology at a premium.  As other competitors come to market the prices obviously come down due to the competitive matrix.  How much did your flat screen TV cost when it first came out versus what it could be purchased for today?  How about calculators?  Or anything else?  You can argue that we're talking about something much more important than TV's, and we are, but these corporations are not set up to help hospitals remain profitable.  They are responsible to their shareholders first and foremost.  Quoting the price per gram of stainless steel stents is clever (and I enjoyed seeing the numbers), but it doesn't even come close to telling the true story.  Do you have any idea how much money it takes to bring one of these stents to market?  Once it gets to market do you have any idea how much it costs to pay a massive team to support it?  I cannot speak for the pharmaceutical industry and reps as I do not work in that sector, but the medical device reps are a critical part of the equation and are a major cost to an organization.

    The other issue, which I found more entertaining than irritating, was regarding the helpless middle aged doctors.  Are you telling me than a balding, middle aged doctor should be expected to simply melt in front of an attractive 28 year old drug rep?  I would immediately lose all respect for one that did.

    Thanks for letting me vent, keep up the great work on the blog!

  • kris

    6/18/2009 3:02:15 PM |

    LoL, Dr Davis, come on, now don't be too hard on 28 years old good looking women?
    there must be a study out there which would show that having good looking people around you (male or female (LOL)) creates a competitive environment to look better which partly leads to paying attention to his or her's own body  which ultimately (hopefully)will lead to a gym close by?
    (although i got your point)
    No wonder the heading "Deep Throat" and the look of the Drug rep came in the same article.
    But point well taken. i will be smiling for years to come when  ever i hear from some body that they are Drug reps specially the good looking ones.
    i read some where that humor is the best medicine (although you have touched a real issue out there which is effecting all of our lives big time).

  • kris

    6/18/2009 3:12:11 PM |

    LoL
    Now come on Dr. davis, dont be too hard on the 28 years old good looking people? there must be study out there to prove that having good looking people around creates a competitive environment and leads one to pay attention to their own body which  ultimately (hopefully) leads them to a nearest GYM.
    (Although i got your point)
    No wonder the the line "Deep Throat" and "28 year old good looking" "hair line Doc" came in the same article but only a thyroid corrective human can put together all the pieces of a puzzle together.
    i believe in that above all, humor is the best medicine and this article will put smile on my face for years to come, when ever i see a good looking Rep.
    (you have touched an issue which is effecting all of us big time our health and our pockets, well done)

  • Charles R.

    6/18/2009 3:38:17 PM |

    Dr. Davis, I love your blog, and find your ideas an approach incredibly useful, and I despise the tactics of Big Pharma, but your conclusions here seem pretty ridiculous.

    Saying that a physician is "helpless" in the face of a good 28-year-old female salesperson is just silly. everything this letter describes is just Sales 101, and is the kind of thing taught in many industries to their salespeople.

    Any doctor succumbing to these kinds of tactics is choosing to do so, and is fully responsible for his/her actions. I have known a lot of physicians, and few of them struck me as being shrinking violets. In fact they were often pretty arrogant and quite convinced of their own superior knowledge. At least around patients.

    If a physician doesn't ask the hard questions, or can't say "No" to manipulative tactics, then all the responsibility is the physician's, not the big, bad salespeople. Physicians are far from helpless, given their extensive education, experience, and positions.

    Many people in many professions have to deal with skilled salespeople in their work, and many manage to act responsibly. "The devil made me do it" isn't an excuse.

  • shel

    6/18/2009 6:18:34 PM |

    your blog is getting better all the time. you have a unique angle as a doctor within the mainstream, speaking out against mainstream activities.

    keep this up and you'll be famous.

  • Anonymous

    6/18/2009 7:19:14 PM |

    We also do not see drug reps in our office.

    We do not accept samples and (even before it became illegal) we've never accepted non-educational paraphernalia (clocks, facial tissue, paper clip holders, etc).

    Occasionally pens would make it into circulation at our office, but we would put them in the back, not for patient use, but for staff use.

    We prescribe generics meds whenever possible. We do not carry samples because it adds an unnecessary dimension to the decision making process for the provider; patients are less likely to actually fill their prescription; if they fill it, they're less likely to remain on it due to the increased copay and it would be expensive to administer samples due to the increased workload it creates for support staff (especially patient phone calls inquiring about needing more samples "until they can get their RX filled").

    I worked with a local GI office during a technology upgrade, and in ONE day over a 30 min period during lunch, the doc had to come up from the GI lab to sign the necessary paperwork from FOUR drug reps so that his staff could get lunch (that he didn't even get to enjoy) and so they could leave samples.

    There were FOUR drug reps in the breakroom, standing around waiting for the doc to finish his last scope. FOUR. I went into the breakroom (unaware of what I was about to walk into) to grab a drink and HOLY COW was it intimidating. Four nice looking, well dressed and social 20-somethings waiting around for the doctor.

    They asked who I was (they know EVERYONE in the office, so being an outsider, I was like fresh meat to them I guess!) and I opened with, "I work at another doctors office, but we don't see drug reps, so I'm not used to being ambushed while taking a break! I feel like a celebrity! You'll have to forgive me *smile*"

    They laughed and then proceeded to question why we don't allow reps.

    I explained the aforementioned reasons and one person asked, "how do your patients who don't have much money afford care without free samples?"

    Simple: "We're a family practice office that is open every day of the year. Every Saturday. Every Sunday. Every Holiday. Patients can see us every day of the year and pay their $10 copay rather than incurring the cost of an ER visit. With the money that saves them, they can afford the generic medications we most often prescribe."

    It was quick end to a slightly uncomfortable conversation!

    -JL

  • kris

    6/18/2009 9:19:09 PM |

    i was hopping the you do that. thanks

  • Dr. William Davis

    6/18/2009 9:55:15 PM |

    I believe that the drug reps intentionally prey on vanity--they appeal to the doctor's need to show their knowledge, the need to exert their "alpha male" dominance. And it works.

    Such is human weakness.

  • Ganesh Kumar

    6/19/2009 3:53:53 AM |

    I think Dr Davis is right! I knew pretty women being hired by Citibank worldwide as "Relationship Managers" to get customers to fork out monies on various bank schemes and mutual funds...did not realize this has penetrated even the drug industry! Possibly due to same "string of owners" owning both industry? Just a food for thought!

  • Anonymous

    6/19/2009 5:54:34 AM |

    Although an exaggeration (somewhat) here is a humorous take on this topic from the daily show:

    Dr. Spin, Medicine Woman

    Thanks to Cristin Duren, pharmaceutical rep and Miss Florida 2006, Dan's now on Lipitor, Zyrtec, Nexium, Celebrex and Wellbutrin; also, he's had an erection for over 96 hours.

    http://www.thedailyshow.com/video/index.jhtml?videoId=117138&title=Dr.-Spin,-Medicine-Woman

  • Lee

    6/19/2009 9:31:53 AM |

    My brother used to be a pacemaker sales rep. These reps are usually made more welcome, since they help administer the devices and there are differences between companies' offerings which need explanation. Even so, he said the industry is based on bribery. The bribes are usually offered in the form of paid trips to conferences or sporting events.

    He said some doctors only accept trips to events that they consider professionally legitimate and do not intend to reward the salesman. But the salesman is not disappointed; he knows that he has still caught his fish. It is impossible for the doctor not to feel grateful. Sooner or later, the doctor will give the company's product a trial.

  • Sifter

    6/19/2009 6:35:09 PM |

    C'mon, you never bought a piece of jewerly from that hottie behind the counter? Sex appeal works, for all business, why should Big Pharma be any different?

    I generally agree with most of your criticisms.... my dad is a retired pharmacist, he'd be the first to denounce the bad antics and overpricing of meds, but that's the way it is.

    By the way, my doctor buddy in Glenview used to get cute reps taking him out Friday nights to get his name put on microbrewed beers, not to mention the $300 'dinners' at Hugo's Frog Bar for taking a 1 hour 'interview.'  Better to expose the side effects of Lipitor, etc then to bust some 28 year old for trying to make a living.

  • Dr. William Davis

    6/20/2009 12:30:49 AM |

    Sifter--

    You "c'mon":

    This sounds much like the testimony offered by tobacco industry representatives when asked why they continued to promote cigarette smoking when they had crystal-clear data implicating cancer causation: "Well, I had to pay my mortgage!"

    The ends do NOT justify the means. In my experience, drug industry representatives are a self-serving, money-grubbing lot out to advance their own careers. If they have to sell their souls and compromise their conscience and the health of other people . . .well, the truth be damned.

    I don't buy it.

  • Anonymous

    6/20/2009 3:54:15 AM |

    This excerpt is so true.  I was just on a vacation and met a really attractive young couple who sell pharma.  She was a model and he is former military, just like the article said. LOL

Loading