The “Incidentaloma”: Coronary Artery Disease “Hiding” in Your Medical Records
Case Presentation
A 57-year-old female competitive mountain biker presents to the cardiometabolic clinic for risk assessment due to a family history of premature coronary artery disease. Her younger brother died of a massive heart attack 2 years ago at the age of 51. He was also extremely fit, and she is worried that despite her very active lifestyle she may be at risk for heart disease.
Two months ago, she crashed on her mountain bike and was seen in the Emergency Department. A CT scan was performed and identified a fractured collarbone along with a few ribs. She was told there were no other organ injuries and she was very lucky.
As an astute clinician, you pull up the CT scan images and begin scrolling through them. You notice coronary calcification of the left main, left anterior descending (aka "Widowmaker"), and right coronary arteries.
In the "Body" of the report under "Heart" it reads "mild coronary artery calcification," but no mention is made in the "Impressions."
She is stunned and a bit disappointed that the Emergency Room physician did not mention this at the time, nor did her Primary Care Provider pick up on it at her follow-up appointment.
Flying Under the Radar
As coronary artery calcium (CAC) CT scans have emerged over the past several decades as a superior preventive screening tool for ASCVD risk assessment, much attention has been given to how to address other "incidental" findings such as lung nodules, tumors, or other suspicious lesions. In medical parlance, we call such findings "incidentalomas."
However, not a lot of attention has been given (until perhaps recently) about "incidental" CAC found on non-cardiac Chest CT scans.
As preventive specialists, we use this "trick" frequently to help identify advanced atherosclerosis and to justify intense preventive therapies. Sadly, these findings are often not mentioned by the Radiologist in the report.
When they are mentioned, they are frequently not included in the "Impression," which is where most referring providers quickly jump to when reviewing the final report. But even when something like "vascular calcifications" or "atherosclerosis" does make it into the "Impression" of a radiographic report, the diagnosis is seldom entered into the patient's problem list.
Years later, when it does eventually get discovered (hopefully not following an ASCVD event), it can represent a frustrating moment for the patient, who's left asking (appropriately): "You mean it was in my chart all along and nobody told me? Why?"
It's a welcome surprise then when a patient is referred by another specialist after discovering atherosclerosis on some unrelated imaging study. It doesn't have to be a Chest CT. It may be MRI surveillance for prostate cancer, or vascular calcification seen on an ankle X-ray or mammogram.
The identification of coronary or other atherosclerosis is the critical first step in getting patients into the right treatment pathways which may prevent atherosclerotic death or serious life-altering complications.
CardioAdvocate Checklist
For Those Without Established ASCVD or Coronary Atherosclerosis
Step 1: Review Prior CT Chest Reports
- Look in the "SUMMARY" or in the body of the report under "HEART"
- Was the presence or absence of coronary artery calcification or atherosclerosis mentioned?
Step 2: If Present
- Was it qualitatively assessed (mild, moderate, severe)?
- Was a follow-up dedicated CAC CT offered to quantitatively help guide:
- Intensity of lipid-lowering therapy?
- The need for aspirin?
- Follow-up dedicated CAC CTs may be indicated if it is likely to alter management (NLA Guidelines)
- Has treatment been offered or discussed?
- If not, bring this to the attention of your provider
- If so, has this been reviewed by a cardiometabolic specialist?
Step 3: If Absent
- Awesome! That makes it less likely that CAC is present, or at least not severe
- Caveat: Standard Chest CTs are not "gated." "Gating" is where they time the picture-taking between beats of the heart so it's not blurry. Therefore, non-gated studies may miss some coronary artery calcification.
- If risk factors present, consider dedicated CAC CT
Step 4: If Report Doesn't Mention Findings
- Bring this to the attention of your provider so they can either:
- Review the films personally, if qualified
- Refer to a cardiometabolic specialist who can perform a comprehensive review, if indicated
- Address this with the Radiology group as a quality initiative
- Consider a CAC CT to formally assess, if indicated
- Typically anyone over age 40 or 45 with at least 1 additional risk factor
- Patients younger than 40 with multiple risk factors may be considered for CAC testing
Clinician Assessment
- Review all prior chest imaging in patient chart for incidental CAC
- If qualitative CAC present, calculate/refer for formal CAC scoring
- Assess risk based on CAC score and clinical factors
- Order baseline lipid panel and consider advanced lipid testing
- Initiate appropriate preventive therapy (statins, aspirin, etc.) based on risk
- Ensure diagnosis is entered into problem list
- Provide patient education about atherosclerosis and treatment
- Consider periodic follow-up imaging based on risk stratification
Deep Dive
CAC Reporting: A Critical Gap in Care
While it might be the first time anyone addressed this finding with the patient and appropriately updated the problem list, this isn't actually a "new" finding. It was there all along—buried in the medical record in the form of 1's and 0's. The "data" exists, but a human practitioner was never aware.
In many cases, the fist-sized organ in the left center chest—the heart—is either ignored completely, or a passing comment is made about its size (normal, enlarged, etc.). But occasionally (and getting better), the Radiologist will make note of the presence of "coronary artery atherosclerosis" and place it in the body of the reports under "HEART." But it rarely ends up in the summary interpretation, which is often the only place the referring provider looks to find the key elements of the report.
Failure to report CAC on Chest CT represents a "missed opportunity" to identify advanced atherosclerosis and implement preventive measures.
Reporting of incidental CAC has been demonstrated to increase awareness and statin utilization (NOTIFY-1 Project), improving population health outcomes.
Formal CAC Testing for Incidental CAC on Chest CT
The National Lipid Association Scientific Statement on coronary artery calcium scoring states it's reasonable to proceed with formal CAC CT scoring when qualitatively mild CAC is seen on non-dedicated chest CT.
It states that qualitatively "moderate or severe calcification generally correlates with a CAC score of >100, a guideline-based indication for statin benefit."
Furthermore, it notes that "a CAC score > 300 is associated with proportionately higher ASCVD risk than those with scores >100, a finding suggesting benefit from greater LDL-C lowering."
It further states that "A CAC score >1000 is associated with an annual risk similar to that of the placebo group in the FOURIER trial, a finding consistent with the potential value of very aggressive LDL-C lowering along with other ASCVD risk reduction strategies."
Thus, there may be utility, in terms of guiding aggressiveness of LDL-C lowering, for formal CAC assessment in all cases of incidental CAC on CT Chest, if it will alter management.
On the other hand, if the decision has already been made to maximally treat an individual patient with very aggressive LDL-C lowering, formal CAC CT imaging may not provide any additional value.
Future of CAC Detection: Deep Learning
Perhaps repeat formal testing will soon be unnecessary if deep learning (DL) algorithms can be used at the time of a non-gated CT scan. Recent research showed that DL-CAC > 100 was associated with higher all-cause death and adverse cardiovascular outcomes compared to traditional risk factors.
This represents an exciting frontier in automated risk assessment and may help overcome the current gap in CAC reporting.
The Bottom Line
Key Takeaways
- Incidental CAC on routine CT chest scans is common and often overlooked
- CAC is a sign of atherosclerosis and indicates cardiovascular risk
- Many radiologists do not report CAC, and when they do, it's often buried in the "Body" not the "Impression"
- Referring providers frequently miss these findings because they only read the "Impression"
- If CAC is found on any imaging, it should trigger formal evaluation and risk stratification
- Formal CAC scoring may help guide intensity of lipid-lowering therapy
- After diagnosis, atherosclerosis should be entered into your problem list
- Review all old imaging reports in your medical record for CAC findings
- Educate your providers about incidental CAC—it's a missed opportunity if ignored
- Incidental CAC should lead to appropriate preventive therapies and specialist referral
