Impacting Care through the Ludeman Center NetworkAmy Huebschmann, MD Devin Lynn Oct 27, 2021
At times, opportunities for the Ludeman Family Center for Women’s Health Research to have an impact on health occur rapidly, such as when when there are shifts in healthcare delivery policies and procedures. That was the case in December 2020, amid a COVID-19 pandemic surge, when UCHealth received a mandate to start using a new laboratory assay to measure the early signs of a heart attack in patients – the ‘troponin’ laboratory test. The relevance to the Ludeman Center is that this new laboratory assay for the troponin test is one of the first tests to recommend different normative values for men and women. This shift in assay was expected by mid-2021, but the timeline rapidly accelerated as the supply line for the old troponin assay was shut down sooner than expected. Physician leaders in cardiology and emergency medicine at UCHealth were tasked to quickly update and approve the protocols for use of the new laboratory test, as well as train their clinical staff to use them. This type of shift usually takes several months to accomplish, but the team only had a few short weeks to meet the transition date when the old troponin assay would no longer be available, and the new assay must be used.
The rationale for sunsetting the old test assay reflected an international shift among health systems to use newer troponin assays that have a higher sensitivity for identifying heart attacks. The main advantage of these high-sensitivity assays is that a negative test provides greater reassurance that a patient is not having a heart attack, and this greater reassurance allows emergency department clinicians to safely discharge patients earlier and limits the number of patients who require additional diagnostic procedures that are sometimes invasive.
As part of improving the performance of the troponin assay to be more sensitive to heart attacks, consideration was given to developing sex-specific cutoffs of ‘normal’ values for men and women. The troponin assay is one of the first tests to create these sex-specific cutoffs. The rationale for these cutoffs is that the ‘normal’ level of troponin enzyme circulating in the bloodstream is lower for women than it is for men. Accordingly, a ‘high’ value in women (15 ng/L) is significantly lower than a ‘high’ value in men (20 ng/L). However, making a clinical diagnosis of a heart attack goes beyond this simple ‘high’ or ‘low’ initial reading. This is because several other conditions may cause mild, chronic elevations in the troponin test, such as chronic heart failure and chronic kidney disease as well as other cardiovascular risk factors. In contrast, during a heart attack, the troponin levels will rise precipitously as that enzyme is leaked from a person’s heart muscle that is lacking adequate blood flow. Thus, it is the time trend of rising troponin levels that is consistent with a heart attack. The implementation of an emergency department protocol for this new troponin assay needed to pick cutoff values that would provide a good ‘signal-to-noise’ assessment with consideration of sex differences not just for the baseline initial test, but also for what signifies a clinically important change in troponin level over time for women as compared to men. Although the population-level norms for ‘high’ value in women and men at baseline were fairly well-established by the manufacturer, the guidance on sex-specific differences in time trends for troponin levels had been generated in a few small studies as of December 2020, offering less guidance on the appropriate thresholds for the Denver metropolitan population.
A small team of clinicians were tasked with updating these protocols – including Larry Allen, MD, associate head of clinical affairs at the CU Division of Cardiology, Karen Ream, PA, and Todd Clark, MD. Their specific task was to work together to incorporate the information about troponin tests into the decision-making process for the new test for the Emergency Department and Cardiology inpatient service, including decision trees (aka ‘pathways’) used regularly by clinicians in the UCHealth Emergency Department. These pathways need to be accurate, but not overly burdensome for use by time-pressured clinicians.
As the Cardiology and Emergency Department leads worked with the UCHealth communications team to alert clinicians to the coming changes, Amy Huebschmann, MD, researcher at the Ludeman Family Center for Women’s Health Research, contacted Dr. Allen about the troponin cut-off transition. Input from other colleagues around the country on best practices for implementing these new assays was critical to developing the most appropriate protocols on a warp-speed timeline, so Dr. Allen encouraged Dr. Huebschmann to leverage the Ludeman Center’s existing network of international experts in sex differences in cardiovascular disease. Dr. Huebschmann and Ludeman Center Director Judy Regensteiner, PhD, quickly reached out to the Ludeman Center Scientific Council, a nationally recognized advisory group of scientists, and summarized their expert input for the UCHealth team. Next, Dr. Allen, Ms. Ream, Dr. Clark, and their team incorporated this information into their existing environmental scan of the potential cutoff thresholds to use and worked quickly to update the decision tree protocols in a way that incorporated sex differences more appropriately.
The result of this revision is that the new troponin lab tests and decision pathways will help to diagnose heart attacks in a way that accounts for sex differences and that follows best practices in the field. This should translate into missing fewer heart attacks over time, particularly for women whose heart attacks have traditionally been underdiagnosed.
Today, the team at UCHealth is working to understand the effects of the new assay and the protocols. They are reviewing how well the current pathways have performed in our Emergency Department, as well as reviewing the scientific literature that now includes larger clinical trials than when they had to implement the new troponin assay in December 2020. The UCHealth team is using the new data to revise their pathways, so that they can continue to improve the early diagnosis of heart attacks for women and men.