Affect Heuristic,COI, or Lack of Knowledge? Why Do Cardiologists Overestimate Benefits of PCI in Stable Angina?

A recent study in JAMA Internal Medicine by Goff and colleagues made me wonder if the Cardiologists studied are uninformed of the limited benefits of stenting (PCI) for chronic stable angina, do they have too strong of a conflict of interest due to economic gain, or is the affect heuristic playing a big part? Probably  a mixture of them all. The COURAGE Trial taught us that PCI was better than medical therapy at reducing anginal symptoms but wasn’t any better for reducing MI and death.

Goff and colleagues reviewed 40 recordings of actual encounters of Cardiologists with patients being considered for cardiac catheterization and PCI. I am unsure if these were video recordings or audio recordings. As best I can tell these were all private practice Cardiologists.  Cardiologists either implicitly or explicitly overstated the benefits of angiography and PCI. They presented medical therapy as being inferior to angiography and PCI (a statement that defies the findings of the COURAGE trial). In fact, in only 2 of the encounters did they state PCI would not reduce the risk of death or MI. These Cardiologists also didn’t use good communications styles that encouraged patient participation in the decision making process.

Why might these Cardiologists do this? They could be uninformed of the limited benefits of PCI in stable angina, but I doubt it. COURAGE was a landmark publication in one of the world’s most prominent medical journals. I find it hard to believe that Cardiologists wouldn’t be aware of the results of this trial.

They certainly have a financial stake in their recommendations.  The image below shows that a diagnostic cath is reimbursed at approximately $9,000 while a PCI with DES is reimbursed at approximately $15,000. That has to have an impact on decision making. I don’t accuse these Cardiologists of doing a procedure only for money but subconsciously this is playing a role. Recommending medical therapy only gets you an office visit reimbursement (maybe $200 or so).

What about the affect heuristic? My colleague Bob Centor writes about this often in his blog. A heuristic is a quick little rule we use to make decisions. The affect heuristic is a particular rule we use that is based on our emotions about a topic. Do I like it? Do I hate it? How strongly do I feel about it? The affect heuristic leads to the answer to an easy question (How do I feel about something?) serving as the answer to a much harder question (What do I think about something?) Its not hard to imagine (and data in the Goff paper supports this) a Cardiologist feeling that PCI is beneficial and should be done. They are emotionally tied to angiography and PCI….they have seen patients “saved” because of this procedure.

So what can be done? The solution is harder than determining the problem (as is often the case). The easiest solution is for insurance companies to stop reimbursing for the procedure in stable angina unless patients have failed optimal medical therapy but this is draconian. I also worry that patients will then receive bills for unreimbursed  catheterization charges. I think using the technology that was used in this study combined with feedback could be useful but logistically impossible. I have always wondered why we don’t use secret shopper fake patients to evaluate physician skills and knowledge (of course the answer is a logistic one) instead of the MOC system. Just publishing a study doesn’t work if physicians don’t read or if they don’t use that study to answer a clinical question. Patient decision aids (like this excellent example) could be very useful but the physician would have to use the tool and many don’t even know they exist.

Some would argue EBM has failed again. A well done study was published and it hasn’t made a difference. The principles of EBM have not failed and in fact, if they were used, could limit the inappropriate use of PCI in stable angina patients. What has failed is the desire to learn and use these skills by the older Cardiologists in this study. Like many physicians, they rely on outdated knowledge and emotions or beliefs. As stated by Bob Centor in a post about the affect heuristicDecision making bodies have biases. Until they understand their biases, we will have the problem of unfortunate, unnecessary and potential dangerous unintended consequences“. In this case the Cardiologists are the decision making bodies and the unintended consequences are the MIs, strokes, renal injury, and death that can and do occur from cardiac catheterization.

Hopefully you are now aware of what the affect heuristic is and how it impacts decision making. Acknowledge it and separate your feelings about a topic from the data. Your patients will benefit.

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