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Obstacles for the Application of
Evidence Based Cardiology
Ricardo Hidalgo Ottolenghi, MD
CECARDIO, Centro de Cardiología,
Cirugía Cardiovascular y Neumología
Instituto Superior de Postgrado, U.C. Quito. Colegio de Ciencias de la Salud,
Universidad San Francisco de Quito. Quito, Ecuador
All through history, medical knowledge has been based principally on experience. Traditionally, the experimented professional has had more recognition than the novice and the one with gray hair has established an "external appearance of knowledge." Just as the wear of long and black wardrobe expressed authority and dignity of surgeons in the past, the white robe turned later to be a symbol of neatness and authority that characterizes the physician of this century. In addition to these external symbols, talking about their own experiences in certain clinical situations, has been the classical way with which a doctor gives confidence to his patients.
On the other hand, patients do not express concern about how many courses or studies his physician has taken, instead, referring to their symptoms they ask if the doctor "has seen similar cases in the past." The absurdity of this situation is that there is no way to prevent a doctor of committing the same mistake again and again, and call this "experience."
Until recently, the majority of therapeutical methods used in medicine, did not have scientific support regarding efficiency and tolerability. Since the 80's in the last century, we have seen a true explosion of clinical trials, that actually cause an obligated reference to evaluate new diagnosis's therapeutics.
Therefore the Evidence Based Medicine (EBM) was born, as a new pedagogic and assisting paradigm that consists of composing the competent medical individual with the best evidence available through the method of investigation, considering the patients' preferences and rights.
Among all of the internal medical branches, maybe cardiology has been the one that has produced recently the most random and controlled studies that have given us paths to more knowledge of cardiovascular pathology and, above all, to engage in effective and safe therapeutical alternatives.
In this presentation we will discuss the difficulties that we cardiologists face in the so called Third World to put in practice Evidence Based Cardiology (EBC), in our every day clinical practice. Many of the examples discussed here are related to the Latin-American reality, but it is possible that these issues are extrapolated to other regions.
EVIDENCE BASED MEDICINE: THE PRACTICE
The practice of the EBM requires five fundamental steps that are diagrammed in . From there it will show that its use means a change in habits related to the traditional medical practice. Thus, the practices of formulating a question, searching for evidence, analyze its quality or validity, to synthesize and verify its application in a certain case, and finally evaluate the results; require a periodic study stimulated by the necessity for knowledge and scientific criticism.
On the other hand, it is assumed that we professionals are aware of all research. It is understood that we doctors have enough time to be updated of the changes in medical sciences. It is also believed that research/studies in our practice is very accessible, that it is very organized, that it is easily reached, that medical bibliography is suitable for helping in the medical decisions, and that as specialists, we are very good at summarizing and interpreting the results of the investigations.
The problem doesn't stop there, all of the effort put into the search for better research/studies can be useless if the physician continues to guide himself by his "clinical intuition" to make a diagnosis. Often, the habitual clinical reasoning is limited by various factors, such as; the limited model of the illnesses (partial information of the problem or inadequate valuation of the probable cause), excessive use of clues, or "gut feeling" (the first impression is always right).
Laurence Weed, in 1968, renewed the new idea of clinical history that was called "Clinical History Oriented by Problems" that basically systemizes principle elements of which; Data base, list of problems, schemes related to the problems, and the therapeutical indications and notes of progress. We have added the "explanation or interpretation of the problems" and the necessity to make a "hypothesis".
The synthesis and integration of the problems allows through probable analysis, the formula of one or various hypothesis. According to the epidemiology, that obligates the physician to stop and think, questioning if the problems are related or not. The advantage of making a hypothesis, supported in the Diagnostics Plans (called evidence that proves/discards one or more hypothesis) should respond to the hypothesis established. This simple exercise obligates the reasonable use of techniques or diagnostic testing, avoiding indiscriminating tests or "in series".
A rational practice with a good risk-cost-efficiency relation, consist of selecting the diagnostic test most appropriate for each patient, considering also the sensibility, the specifics, and usefulness for each test, the practicality and the adequate technology. There is nothing more expensive and unproductive than making "routine tests".
1. The Medical Alternative
While we cardiologists make superhuman efforts to practice EBC, our patients look for "homeopaths" and "reflectionists" that are on the opposite side of something that one could consider "based on research", (it seems that the patient isn't exactly looking for evidence in their treatment!).
In our rural communities, more than 80% of the first and second generations of native Indians seek attention from the Shaman. So, does the alternative medicine work? The subject is complex and goes beyond reasonable limits in this field. Maybe the answer is in the fact that "the faith" in the therapy has a correlation on the effects that it produces... To have faith, one must belong to that culture and understand the health-sickness process from that culture. Asked the difference of going to a doctor or a Shaman, one replied that "one goes to the doctor for his knowledge and to the Shaman for his power"...
The mentioned above will always be considered as a tale, if it weren't because these practices without contrasts provoke "interferences" to start the correct treatment (evidence based), in patients with an acute myocardial infarction.
presents a summary of a study conducted during three consecutive years in which there is a percentage of patients that chose alternative treatments for heart attacks before arriving to an emergency unit in a private clinic. The applied treatments go from herbs, "natural patches", aromatherapy, ozonotherapy, chelation with EDTA, extraction of eye teeth, to prostate massages!
With this background, one asks, "How can we establish on time a treatment with aspirin, fibrinolytics, betablockers, ACE inhibitors, among others, based on clinical research?".
2. Habits and Attitudes of General Physicians
Confronting High Blood Pressure
It goes without saying the importance that arterial hypertension has these days. In Ecuador, this pathology prevails in about 22%.
To access the Ecuadorian physicians' attitude toward hypertension, review his theoretic and practical knowledge, the instruments used, and the treatment habits. We made up a questionnaire with 25 closed questions. The investigation was distributed to a group of 1,383 general physicians in 19 provinces chosen at random from a base of 4,000.
Continuing, we will show some of the studies aspects:
2.1 Type of sphygmomanometer
79% of the interviewed physicians used aneroid sphygmomanometer, 16% mercury, 3% automatic, and 2% "other". In , it will show the frequency of calibration in the various instruments used to determine arterial pressure (AP). It is alarming the amount of professionals that never calibrate their equipment and those that do not answer, reaching 98%. As little as only 1.8% of the interviewed admitted to calibrating irregularly (every six to twelve months).
2.2 Measuring techniques
83% of the interviewed physicians said that to "steady" the head of the phonendoscope, they would put it between the patient's arm and the instrument's handle. On another note, when asked how they determined the diastolic AP, 77% of the physicians answered that they used the IV phase of Korotkoff, and 19% the V phase.
2.3 Other aspects
To save space, we will not comment on the diagnostic criteria, the extent of research treatment measures, frequency of controlled appointments and treatment observations. We ask that readers interested in the original publication to send a request for it.
It proves alarming the amount of physicians that used aneroid sphygmomanometers without any maintenance or calibration: these facts shows the unimportance that the general physician gives to the AP results, or better yet, or the ignorance of the necessary maintenance that should be performed regularly to equipment for correct results.
Another surprising fact is the poor use of the key techniques to determine the AP. But maybe most alarming is to know that almost 80% of the interviewed professionals confirmed using the IV phase of Korotkoff to determine the diastolic pressure (above all, if we realize the high results of the diastolic hypertension which prevails in our country). And that a similar percentage (83%!) confirms that to "steady" the head of the phonendoscope, they introduce it between the patient's arm and the instrument's handle, causing arterial compression.
95% of the interviewed were updated on the hypertension drugs. Nevertheless, one must consider the fact that the majority of the physicians said that the fundamental factor considered when they write a prescription, was.. the price of the medicine!
Regarding treatment behavior of the physician facing hypertension, it is appropriate to mention a study made in Oxford of 6,000 steel workers. They detected 300 hypertensions not under controlled treatments. They evaluated and confirmed their hypertension in the following three months and sent them to 85 local physicians. Six months later, only 2/3 had received treatment. The reasons to treat or not were: the level of diastolic AP, the patient's age, the presence of lesions in main organs, and the year the physician graduated (the older physicians were more permissive). What else is there to say?
3. Routine Exams in Private Medicine
In our practice when in doubt, it is fair to go to the "Diagnostic Plans" or, look for research that will help in confirming/eliminating hypothesis. To do so, we need to be familiar with the "steps to action". .
Thus, the probability of a patient's welfare from a cardiologist can vary between 0%-100%. The question is: From what probability can we or should we start acting on this illness? Which is the most effective treatment, considering cost and low risk? Does the physician understand the culture in which the research has been conducted? When the physician ask for complementary tests, does he apply the values of sensibility and specifics, or interprets the usefulness of the tests ?
In a concrete case, the knowledge of accuracy and specifics of different tests, such as cost and risks, it is useful to chose the most adequate for the clinical case. It is known that the probability of pre-testing of an illness, known as prevalent. These parameters are related mathematically by the Bayes's Theory.
In, we prove that the diagnostic results of the electrocardiograms of left ventricular hypertrophy (LVH), depends mostly on the true incidence of the left ventricular growth in the population in the study. In the severe hypertension group, 90% has LVH and in this text the possibilities that a positive EKG for LVH effectively corresponds to anatomic LVH are very big (97%): while in the group of adults without symptoms, the possibilities that an EKG of anatomic LVH are much less (4%).
Therefore, it is clear that the diagnostic evidence has its indications, precisions, and uses. That is the way it is, at least in theory. Let's see now how it works in the practice.
Recently, various private centers offer and advertise so called medical exams, to "maintain one's health and to find the early signs of illnesses". Interesting, right? Prevention first? Absolutely. Inwe copied the "routine tests" that is used in one of these centers.
It is obvious that the decision to make/or not make an exam depends on what the person can afford. In other words, we are practicing "Measured Medicine" (from the wallet).
4. The Problem with the Experts
The "expertise" in one field doesn't necessarily correspond to qualified methodology. Frequent expressions such as "I do alright", "In my experience", "Take this just in case", "Objectives of one case and a summary of the literature" publications, are just a few examples of our reality.
How to argue with Dr. X, about certain therapeutical conduct, if the answer is always the same: "I have been doing this for years, in my experience, and it works fine?". It's clear, how can we doubt acupuncture.. if the Chinese have been practicing it for years!
The problem is that uncertainty does not end, even for them, and to complicate our lives, even experts disagree. Not to mention the influence of conflicts of interest due to their association with private sectors.
Are we going to reach a method to select experts at random someday?
5. The Impairment of the Relation Doctor-Patient
The scientific innovations have advanced greatly in preventive detection, diagnosis, treatment and healing of diseases. But at the same time (without precedents) a scientific progress is taken place, we are witnessing the loss of humanism, traditionally related to the practice of medicine.
Following this direction, society demands the doctor to be a professional who harmonizes sciences with humanism, understanding this as a skill in words, feelings, attitudes and values.
To apply MBE does not mean, loosing the sacred vision in the doctor-patient relation, considering the preferences and values of a human being who is confronting adverse situations and requires care, understanding and affection.
MBE requires the integration of the individual clinical master, with the best evidence available found throughout investigation...with humanism applied to medicine.
Any stranger who walks into one of our Coronary Units or ICU's and found one of our patients covered with wires, alarms and sensors, may get the wrong impression and wonder if the patient's body is part of a circuit, which is the portion of a circular process, or that he is the organic material that feeds the rest of the mechanism so that the machinery can work (and not the other way around).
And routinely ICU has turned into a scene of monitors with flashing lights and the sound of deep "beeps," long and short, with rhythm and asymmetry. On keeping an eye on catheters and plastic bags that reflects the good or bad cardiac, lung or kidney functions. As someone said about ICU, the patients die with "hunger of the skin."
As we inherited the Cartesian dualism, we have become plumbers of the body instead of physicians of the person. At this point, it seems important to remember that the best available technology is still communication and the best procedure is the mutual trust, based on respect, comprehension and affection.
This critical vision about our own limitations in practicing scientific and humanitarian medicine (this is the way we see EBC), is just the first step that can be improved and increased in the future. After analyzing this material, we can conclude that the situation in our environment is not as bad as we suspected nor as good as we hoped for.
The huge impact that EBM is receiving in teaching as well as in the medical practice, is an undeniable reality. It is a fact that this influence will not stop growing within the next years and it should be reflected in the improvement of the assisting quality, that is why, now more than ever, it is necessary to reinforce and modify the premed, post graduate, and the medical education system in order to meet the new needs.
The Medical Faculties should incorporate these issues, and other paradigms in Medical Education such as PBL (Problem Based Learning), Medical Records Based On Problems, Information Applied To Medicine and Bioethics, not as laws, but as a philosophy of teach-learn.
Opposition against this line of thinking has not waited to appear. There are people who believe that these new paradigms are new age inventions in order to reduce the authority of the scientific chain. This is the reason why changes will not always be easy but challenge is imperative. Now is the time to remember Galilee. In his time, rational science, represented by himself, was expelled from the church, because his discoveries and theories threatened the status quo based on the concept in which earth was the center of the universe. The conservative forces won a temporary victory but history has done justice. After all, the earth continues rotating around the sun and not the other way around.
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