A systematic screening process for relatives of patients with transthyretin amyloid cardiomyopathy (ATTR-CM) showed promising results, according to a recently published study in the European Journal of Nuclear Medicine and Molecular Imaging.
The study showed that cardiac scintigraphy, the imaging technique of choice for diagnosing and assessing ATTR-CM, can detect the condition in its very early stages, enabling physicians to design personalized monitoring and treatment strategies to improve patient outcomes in the long run.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
“Consequently, bone scintigraphy should be incorporated into the recommendations for the evaluation of ATTRv family members, alongside genetic testing, and echocardiographic examination, particularly for individuals approaching the age at which the typical phenotypic expression of their specific TTR variant is observed,” study authors concluded.
Read more about ATTR-CM testing and diagnosis
The study screened 73 asymptomatic individuals related to patients with ATTR-CM because of either hereditary or wild-type ATTR, as well as 27 symptomatic patients with a confirmed ATTR-CM diagnosis. Cardiac scintigraphy detected six patients (8%) with radiotracer uptake consistent with ATTR-CM.
Genetic testing revealed that 20% of relatives had a genetic variant associated with ATTR-CM. None had abnormal findings in cardiac scintigraphy.
After the initial results, researchers divided patients into four groups: symptomatic patients with ATTR-CM, relatives with newly diagnosed ATTR-CM, patients with genetic variants but without ATTR-CM and individuals without genetic variants or ATTR-CM.
Index patients with ATTR-CM were mostly men, were older than patients in the other three groups, had more comorbidities such as diabetes or chronic kidney disease, and had clear biochemical and echocardiographic ATTR-CM findings.
Relatives with ATTR-CM had elevated troponin levels and more electrocardiographic abnormalities than patients with ATTR-CM variants and no radio-uptake abnormalities. Similarly, relatives with ATTR-CM had greater ventricular wall thickness and reduced ejection fraction, findings consistent with diastolic heart failure typically observed in ATTR-CM.
The authors said that only relatives of patients with hereditary ATTR had abnormal findings, suggesting that relatives of patients with wild-type amyloidosis do not require more than the standard cardiac care provided to the general population.
In recent years, ATTR-CM has become an increasingly frequent diagnosis among patients over 65 with heart failure. Thanks to research advances, there are disease-modifying drugs available that can significantly improve survival and quality of life. Early beginning of treatment is critical for efficacy.