Troponin blood tests reliably rule out Fabry heart disease: Study
Patients needing more substantial treatment could potentially be Id'd promptly
High-sensitivity blood tests to measure troponin — a biomarker of heart cell damage — can be used to rule out significant cardiomyopathy, a heart condition, in people with Fabry disease, according to a recent report.
In clinical settings, this could help physicians promptly identify patients in need of more substantial monitoring and treatment, while avoiding resource-intensive MRI imaging for people at low risk.
“Taken together, serial [high sensitivity troponin] assessment appears to be a reasonable approach for detecting early myocardial [heart muscle] involvement in patients with genetically confirmed [Fabry disease],” researchers wrote.
The study, “The Utility of High-Sensitivity Troponin to Detect Cardiomyopathy in Patients With Fabry Disease,” was published in JIMD Reports.
Fabry patients often develop heart disease
In Fabry disease, a fatty substance called globotriaosylceramide (Gb3) accumulates in cells and causes organ damage. Among the most commonly affected tissues is the heart. People with Fabry often develop cardiomyopathy, a disease of the heart muscle that makes it progressively harder for the organ to pump blood.
Cardiac MRI, a noninvasive technique that creates detailed pictures of the heart, is central to identifying and monitoring cardiomyopathy in Fabry. Findings from these imaging studies are used to guide treatment strategies.
However, cardiac MRI isn’t feasible everywhere, particularly in resource-limited areas where these specialized procedures are costly and burdensome for healthcare systems and patients.
The identification of a readily available blood biomarker that could reliably exclude significant FC [Fabry cardiomyopathy] would allow us to prioritise cardiac MRI for patients for whom it is most likely to impact their care.
Moreover, some people who haven’t yet shown signs of cardiomyopathy may wait three to five years before their next scan, potentially allowing heart disease to progress without treatment.
“The identification of a readily available blood biomarker that could reliably exclude significant FC [Fabry cardiomyopathy] would allow us to prioritise cardiac MRI for patients for whom it is most likely to impact their care,” the researchers wrote.
To date, blood biomarkers have served a supportive role in monitoring Fabry’s heart disease. One thing that can be measured is troponins — including troponin I and troponin T — proteins that heart cells release into circulation when they’re damaged. High-sensitivity tests are available to detect even small amounts of these proteins in blood.
While elevated troponins have been described in later stages of Fabry cardiomyopathy, more research is needed to understand whether these proteins are meaningfully increased early on, and if they can reliably be used as a cardiomyopathy biomarker.
To learn more, the scientists retrospectively examined clinical data from 133 Fabry patients who were seen at a center in the U.K. and who had undergone both cardiac MRI and high-sensitivity troponin blood tests.
Among them, 62 people were determined to have cardiomyopathy based on MRI findings, while 71 people did not.
Troponin levels found to have good diagnostic value
Blood levels of both troponin I and T were significantly higher in people with cardiomyopathy than in people who did not have the heart disease. They also had higher levels of NT-proBNP, another heart disease biomarker, and lyso-Gb3, an indicator of Gb3 accumulation.
Additional analyses revealed that troponin levels had good diagnostic value, performing better than NT-proBNP for distinguishing people with or without cardiomyopathy.
For either troponin type, a blood level of less than 8.5 nanograms per liter could reliably rule out significant cardiomyopathy, including in both men and women, and in classical and late-onset Fabry types.
The scientists noted that this cutoff is notably lower than values that have conventionally been used as an indicator of cardiac injury.
Blood troponin levels increased as cardiomyopathy progressed, with higher blood levels correlating with greater severity of cardiac involvement on MRI scans.
The findings suggest that troponin is “a promising biomarker for detecting early FC,” the researchers wrote.
“In clinical practice, the results could then be used to guide the optimal timing of the next [cardiac] MRI. with the potential benefit that patients for whom treatment is indicated are identified earlier, whilst low-risk patients are not subjected to unnecessarily frequent scans,” they added.
While the two troponin types performed similarly in this study, the samples were not always collected at the same time. The researchers noted that a future study would ideally directly compare the two biomarkers to ensure they can be used interchangeably.
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