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Wednesday, November 20, 2013

I'm now a certified ultrasonographer: passing the ARDMS test

I just finished taking an exam for the American Registry of Diagnostic Medical Sonography. Having passed it, I can now put RDMS after my name, standing for Registered Diagnostic Medical Sonographer. The RDMS is a credential that many ultrasound technicians carry, and occasional physicians, especially those who make ultrasound part of their practice. So now, should I ever be at loose ends, I can potentially get a job as an ultrasound tech.

To take the ARDMS qualifying test, one must first satisfy various requirements, which fit into categories meant to include ultrasonographers of great experience, ultrasonographers who have gone through a training program (usually 1-2 years) physicians who studied ultrasonography extensively during their medical school and residency training and physicians whose experience includes extensive review of hundreds of scans by experts. Proving experience requires letters from a supervising teacher. The exam is a proctored 5 hour test, 3 of which is in a specialty area and 2 of which tests knowledge of the physics and technology, with a special focus on safety. Due to the miracle of digital communication, I was able to take the test in my own time frame, in a "Pearson VUE" test site about 90 minutes drive from my home. The test site is in a little office space, but has a silent room with constant monitoring, manual pat downs, and rigorous identity checks. Apparently Pearson VUE is part of a multinational company out of England which owns a large share of the Penguin publishing company and specializes in online learning. It was comfortable and low key. Short of having a cookie break and access to online resources, I can't think of a better set up for success.

The exam is pretty specific. My ultrasound mentor recommended I take a review course which, in combination with quite a few hours of study, would probably result in me passing the test. The review course he recommended was by the company ESP ultrasound, taught by people who specialize in making sure students pass the exam. The course director is Sid Edelman, has been teaching for decades, and covers the ultrasound physics curriculum. When I took the course, I thought that the level of trivia they taught could only have been due to some sort of collusion between the people who write the test and the people who taught the course. After taking the test, I realized that the test questions were not necessarily in the study guides for the exam, but that there was considerable overlap between what the course taught and what we were tested on. Much of the trivia that was taught was referred to in the exam questions, nevertheless, exam questions really required some knowledge of physics beyond what the course tested, and many of the questions were tricky, requiring deduction rather than straight memorization. Preparing students to take standardized tests is a very big business in the US, so even in a narrow field such as ultrasound technology there are many choices, from Pegasus Lectures, providing on-site teaching in Atlanta and Tampa, and Burwin Institute which provides online material. Having a professor to emphasize the important information was really helpful to me. Without it I would have questioned the need to learn such a broad collection of detail, and would have found studying much more frustrating.

The physics part of the exam made me wish I had taken a real, in depth course on how ultrasound works, maybe something on a college level that lasted a semester and made me able to build my own basic ultrasound out of stuff I could buy at the hardware store. Since that was not possible, memory of my distant physics education and frequently consulting multiple sources to explain points that didn’t make sense helped me answer some of the more abstruse questions. Because the real physics of the complex machines we use now is beyond most people, what we learned did not truly represent reality. This was very disappointing to me, since I had hoped I would learn enough to be able to answer some questions about why the technology is so slow to develop. I wonder if the lack of detail also helped protect the companies whose livelihoods depend on producing a competitive product. I’m betting that is part of it, though that’s kind of creepy.

During the part of the course that taught me about  ultrasound of the abdomen, thyroid and testicles, I developed awe for the knowledge most ultrasound technicians eventually have of 3 dimensional anatomy. Even at my very most knowledgeable, just after finishing my first year in medical school complete with cadaver dissection, I had nowhere near the depth of understanding of how the organs are packed into the body and served by so many named blood vessels. Ultrasound has repeatedly sent me back to my anatomy books to try to figure out how things lie in the human body. I will undoubtedly continue to improve, but there are many fresh faced young people with many less years of training, who make only a fraction of my salary, who will always be better at it than I am.

Passing the exam means that I know enough of the anatomy plus technical details and disease processes that I can pass the same exam as my technician colleagues, but our proficiency is in no way identical. I can't compete with the exhaustive knowledge of anatomy a career ultrasonographer has, and he or she can't possibly understand the level of implications of constellations of physical, labratory and ultrasound findings and combine them with patients' stories and priorities. It is good that this test has room for all of us. It could have been written so that either us would routinely fail.

So why take this test? I'm not planning on a career change, after all. Being a doctor is plenty absorbing. I noticed that the ultrasound teachers who I work with usually have RDMS after their names. It is a recognition of competence that need not come with a long explanation. I have always been concerned that some group for whom I work will have extensive requirements for ultrasound credentialing. I envision myself happily examining all of my patients with ultrasound and being told that, no, that was not allowed. So far it hasn't happened, but only because most places I work have no concept of bedside ultrasound, other than perhaps as a method of guiding procedures. It also seems likely that the credential will give both me and any employer some confidence in my ability to actually teach other people. I surely do not believe that an ARDMS test should be mandatory for physicians who employ bedside ultrasound because the requirements are way too cumbersome, but it will, for a few, be useful as a way of communicating competence in a variety of aspects of the practice.

I have been intermittently studying this stuff for about 6 months, including such questions as how fast ultrasound travels in soft tissue and the components of attenuation and how they relate to speed of the ultrasound beam and Snell's law and how it might or might not affect real time ultrasound. I have not yet found a way to make this stuff help me, but I trust at some moment I will look back on my previous grasp of the material and wish I had learned it better.



Thursday, November 14, 2013

Who should take statins? What, exactly, do the new American Heart Association guidelines say, and should we agree with them?

Statins made the news in a big way this week. The American Heart Association, in collaboration with the American College of Cardiology, just released recommendations that should change the way we prescribe medications called statins, including drugs like Lipitor and Crestor and their generics, Atorvastatin and Rosuvastatin. The headlines say stuff like "More Americans may be Eligible to Receive Cholesterol Lowering Drugs!" Boy howdy, aren't we all in for a treat?

Big Money:
I am a bit, or more than a bit, skeptical of news about statin therapy because Lipitor, before it went generic, was responsible for over 6 billion dollars in revenue for Pfizer and since it went generic, Astra Zeneca is raking in more revenue than they did last year for their cholesterol drug, Crestor, at about 1.6 billion dollars. This kind of market influence is associated with significant influence on the attitudes of both physicians and patients through advertising and research support. I think that our love affair with statins cannot be separated from the fact that the sale of these drugs is a significant contribution to our economy.

Nevertheless, I recognize that statin drugs have contributed significantly to heart health since they were first released. Statin drugs were first released in 1987 after some false starts. The earliest statin caused muscle breakdown and killed some of the dog's upon which it was tested. Lovastatin, which was considerably less toxic was the first statin to be released. Statins reduce cholesterol by inhibiting an enzyme, HMG CoA reductase, but also stabilize the walls of blood vessels and reduce inflammation. In so doing, they reduce the risk of heart attacks, which are most commonly caused by obstruction of one of the coronary arteries by atherosclerotic plaques which rupture and form a clot that blocks blood flow to heart muscle. Inflammation is important in this process as well.

It has been known for decades that a high level of cholesterol in the blood is associated with increased heart attacks, as well as other conditions related to blood vessels such as strokes. Therapy to reduce cholesterol sometimes reduces the risk of these conditions, and many studies have been done looking at ways to reduce cholesterol. Not everything that reduces cholesterol reduces heart attack risk, though, and reducing the cholesterol and fat in the diet does not have a very significant effect on either overall cholesterol levels or on heart risk. Statins, though, do reduce the cholesterol level quite significantly and also appear to reduce the risk of various vascular events.

The Controversy:
Heart disease is the leading cause of death in the US, so reducing the risk, even a little bit, has the ability to save many lives. Statins do reduce the risk of heart attacks, but for most people, only a little bit. In the patients most likely to benefit, those who have had heart attacks and so are at risk of further disabling recurrent heart attacks, as many as one in 29 patient who take statins for 4 years will avoid having a recurrent heart attack or death when compared to patients who do not take statins, as reported in a recent meta-analysis. For patients who haven't had heart attack, the chance that taking a statin will prevent having one is lower, for women 1 in 148 over 4 years. Statins do have side effects, from annoying symptoms like gas and muscle pains to more significant ones like memory loss, weakness and diabetes.  In fact, the chance that a person with low to moderate risk of heart disease will get diabetes as a result of statins is quite a bit higher than the chance that he or she will be saved from having a heart attack. Dangerous and sometimes life-threatening muscle destruction with associated kidney failure is a rare but real side effect, which I have seen in practice. Significant side effects plague 18% of patients who take statins. A very good article, looking at controversies related to statin therapy, written by a professors from Harvard Medical School and UC San Francisco who question the mainstream belief in these drugs' effectiveness and safety, can be found in this week's New York Times. The vast amount of scientific data on statins is interpreted differently by different experts, but the way I look at it, in the patients at greatest risk for heart disease, 29 people have to take a statin for 4 years in order to save one of them from a heart attack. For patients at lower risk, the numbers are even less convincing. In the lower risk patients evaluated 148 have to take a statin for four years for one of them to not have a heart attack, which means that 147 patients take the drug, along with its side effects, for 4 years to no good purpose.

The major issue, beyond the economics and financial interests of drug companies, revolves around differing views of our mission as doctors, and also around differing experiences of physicians involved. If a person is a cardiologist, avoiding heart attacks is practically the only thing that matters. Cardiologists rarely see their patients for problems other than those related to their heart problems and don't face the day to day difficulties related to statin side effects. When a patient has muscle pains and cramping or stomach distress, he or she doesn't usually expect the cardiologist to resolve the problem. Cardiologists are great champions of statin therapy. Large organizations, such as the American Heart Association are also great champions of statins. The big picture for them is that a small effect on decreasing heart attacks, multiplied over millions of people who might take statins, means many lives saved. As a physician who treats individual patients, however, and as a person who may someday be a patient, I find it hard to advocate taking a drug with a very complex range of effects for a very small chance that it will make a positive difference. Even if we believe that our responsibility to the population is more important than to the individual, how do we assign value to patients whose lives are potentially saved against the much greater number of patients who feel just a little bit sicker because of a medication we prescribe?

The New Guidelines:
This week, to great fanfare, a new approach to prescribing statins was introduced. Many experts reviewed the extensive research, focusing on randomized controlled trials which are the most rigorous way to evaluate effectiveness. They were interested in finding the most effective and efficient way to reduce heart attack risk by influencing cholesterol. They looked only at statin therapy, since the vast majority of good research was on statins, as opposed to, say, fish oil or niacin or fiber or chelation therapy. They found that the most efficient way to reduce heart disease risk with statins was to check the cholesterol of all patients over the age of 40, and treat those with high risk of heart attack with either moderate or high doses of statins. The patients who should be encouraged to take statins are in one of 4 groups:
  1.  Patients with LDL cholesterol greater than 189, who probably have a genetic condition that puts them at very high risk of heart disease. 
  2. Patients between the age of 40 and 75 with diabetes, whose LDL levels are above 70 (very low.) 
  3. Patients with prior heart attacks.
  4. Patients with a 10 year risk (see this risk calculator) greater than 7.5% of having a heart attack.

They recommended not checking cholesterol levels compulsively in order to reach certain set goals, though they do recommend checking the occasional level to see if the patient is actually taking the drug. It appears that treating to a target is very energy consuming and encourages us to add drugs that don't have evidence of effectiveness. In my experience, it can lead to focusing on numbers rather than on humans, but can also be the basis for conversations that might lead to more exercise and healthier living. Still, not focusing on cholesterol numbers will free us up to pay attention to issues of patient care that are probably more valuable. There were no good studies on treating patients over 75 with cholesterol lowering drugs, other than those with prior heart attacks, but it seemed likely that they would benefit. No recommendations are made for these folks, other than that they should discuss pros and cons with their physician.

Regarding side effects, the general implication of the article was that patients with muscle pains on statins should try to take them anyway, and that doctors should make sure to ask the patient before starting therapy if they had muscle pains so they could counter any complaints with the assertion that they had this before starting the drug. Having treated patient with statin therapy for years, I think that muscle pains are a very common side effect and can be disabling. I think that minimizing the importance of these symptoms by telling a patient that they should continue to take the medication that causes this will potentially reduce patients' quality of life and overall activity level. I am disappointed in the way this issue was handled.

One very interesting implication of this study is that an elevated cholesterol alone does not mean that a patient should be on a statin. Many people who are concerned about their health take a statin for an elevated cholesterol level, but their risk of heart attack is extremely low, so taking a statin will do nothing to improve their health. This is a positive development.

These new recommendations may be somewhat better than the rather random approach to cardiac risk reduction related to cholesterol that existed before, but are likely to overtreat patients without heart disease, resulting in patients whose health will be worse related to side effects, and who will be more dependent on the health care system because they will now be taking a drug. The guidelines will allow some people to stop taking their statins, which is good. I feel suspicious of the huge media coverage of this recommendation (most treatment recommendations get no news exposure) and I do expect that all of the free publicity will substantially increase the revenue of the companies that make statin drugs.