The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in patients undergoing transcatheter aortic valve replacement (TAVR) for severe aortic stenosis may be lower than previously estimated, according to a new study published in the European Journal of Nuclear Medicine and Molecular Imaging.
The study analyzed a contemporary TAVR cohort, revealing that among 380 patients, 20 individuals (5.3%) exhibited a positive scan for ATTR-CM. Further investigations confirmed ATTR-CM in 17 of these 20 patients (4.5%).
One patient opted not to undergo confirmatory testing, while the remaining positive scan was linked to light chain amyloidosis. Additionally, 1 patient had a negative biopsy result.
“The prevalence of ATTR-CA [ATTR-CM] in contemporary patients referred for TAVR may be lower than previously described due to the expanded indication to patients at lower surgical risk,” the study’s authors explained. “Nevertheless, given the new treatment options for ATTR-CA, the risk is sufficiently high to warrant selective, but not universal screening.”
Read more about ATTR-CM epidemiology
The study also suggests that using N-terminal pro-brain natriuretic peptide (NT-proBNP) as a screening tool could enhance the accuracy for identifying patients at risk of developing ATTR-CM.
Comparative analysis of patient and echocardiographic measures revealed that increased levels of NT-proBNP (cutoff of 1000 ng/L) was the most effective parameter for identifying individuals who should be referred for a technetium-99 pyrophosphate scan (99mTc-PyP scan). NT-proBNP demonstrated a sensitivity of 90% and a negative predictive value of 99%.
Conversely, an abnormal left ventricular mass index showed limited sensitivity (75%) and specificity (58%) for detecting ATTR-CM.
The study involved the screening of 380 patients aged 70 years and older with severe aortic stenosis. Patients were referred for a 99mTc-PyP scan to detect ATTR-CM. The primary outcome of the study was the percentage of patients with a positive scan.
Abadie B, Ali AH, Martyn T, et al. Prevalence of ATTR-CA and high-risk features to guide testing in patients referred for TAVR. Eur J Nucl Med Mol Imaging. Published online August 22, 2023. doi:10.1007/s00259-023-06374-2