Dr Scratchy,
I'm reading the document you posted above. Thank you. But I'm trying to understand something. I'm looking at the flow chart for primary prevention. In the green box labeled "risk discussion" under the line ≥7.5% - ≤20%, it says
"If risk estimate + risk enhancers favor statin, initiate moderate..."
What exactly do they mean by that? Ie the "+" sign. Do you have to have both estimates and enhancers? Or just one or the other? How many enhancers?
And then under that they say " if risk decision is uncertain : consider measuring CAC". What would make the decision "uncertain" ? The number of enhancers?
Thanks again.
bmcgonig,
Before going on to try to answer your question, please note that I don't treat patients for cardiovascular disease. I'm in another specialty. I recommend the ACC/AHA Guidelines because I believe they were written by well qualified people who reviewed the available evidence critically. I loved this earlier post:
Every dr I have been to all suggest staying on it. Perhaps they are dumb as hell but I know I'm dumber than them so I will take their advice.
It's very funny and also rings true-the current Guidelines will surely evolve and may be proven erroneous, as so much medical dogma has, but they are certainly more reliable than unvetted information offered by someone in a forum.
Back to your questions about the Chart, which are very good ones and the answers not immediately obvious to me-I went back to the Chart and also briefly reviewed portions of the full Guideline from which the Chart was excerpted. In fact, as I read the Chart, I'm struck by how complicated it is. It is trying to assimilate a large number of risk factors, available tests and medical and lifestyle interventions into a single flowchart. Note that the chart, and the Simplified Guidelines, are excerpts from the full 2019 Guideline on the Primary Prevention of Cardiovascular Disease. This Synopsis from the full Guideline is a little long but I think it does address both of your questions regarding the role of the risk enhancers and CAC test:
Synopsis
Assessment of ASCVD risk remains the foundation of primary prevention. Although all individuals should
be encouraged to follow a heart-healthy lifestyle, estimating an individual’s 10-year absolute ASCVD risk
enables matching the intensity of preventive interventions to the patient’s absolute risk, to maximize
anticipated benefit and minimize potential harm from overtreatment. The 10-year ASCVD risk estimate
is used to guide decision-making for many preventive interventions, including lipid management (S2.2-4,
S2.2-36) and BP management (S2.2-37); it should be the start of a conversation with the patient about
risk-reducing strategies (the “clinician–patient discussion”) and not the sole decision factor for the
initiation of pharmacotherapy (S2.2-4, S2.2-36, S2.2-38). All risk estimation tools have inherent
limitations, and population-based risk scores must be interpreted in light of specific circumstances for
individual patients. The PCE have been shown to overestimate (S2.2-15, S2.2-39–S2.2-47) or
underestimate (S2.2-12, S2.2-48–S2.2-51) ASCVD risk for certain subgroups. Thus, after calculation of
the PCE, it is reasonable to use additional risk-enhancing factors to guide decisions about preventive
interventions for borderline- or intermediate-risk adults (S2.2-4–S2.2-14). However, the value of
preventive therapy may remain uncertain for many individuals with borderline or intermediate
estimated 10-year risk, and some patients may be reluctant to take medical therapy without clearer
evidence of increased ASCVD risk. For these individuals, the assessment of coronary artery calcium is a
reasonable tool to reclassify risk either upward or downward, as part of shared decision-making. For
younger adults 20 to 59 years of age, estimation of lifetime risk may be considered. For adults >75 years
of age, the clinician and patient should engage in a discussion about the possible benefits of preventive
therapies appropriate to the age group in the context of comorbidities and life expectancy.
So my interpretation is that if you are in the intermediate risk group, i.e. ≥7.5% - ≤20% risk estimate, then you and your doctor should consider whether any of the "ASCVD risk enhancers" are present and sufficient to warrant statin therapy. And you may also consider getting the CAC test in inform your decision. Without reviewing the Guidelines in detail, I believe, if you are in the intermediate risk group, there are no absolutes in terms of number of enhancers that would indicate the threshold for recommending initiating statin therapy has been crossed. So there is fairly wide discretion at the intermediate risk level, presumably reflecting the limited benefit:risk ratio of statin therapy in this risk group.
I hope this answers your questions or at least provides a launch point for getting the answers and more-the full and simplified versions of the Guidelines really contain a great deal of excellent information.
Good wishes,
Scratchy
