Amyloid-associated calcium deposits

Amyloid-associated calcium deposits are pathological accumulations of calcium salts, primarily hydroxyapatite, that co-localize with transthyretin (ATTR) amyloid fibrils in the heart (Statsperi et al., 2020, J. Nucl. Cardiol.). These deposits are a defining characteristic of transthyretin cardiac amyloidosis (ATTR-CA) and are significantly more prevalent and dense in ATTR deposits compared to light-chain (AL) amyloid deposits (Fine et al., 2017, Circ. Cardiovasc. Imaging). While the exact biological mechanism triggering this calcification remains under investigation, it is hypothesized to involve the specific biochemical environment created by ATTR fibrils that promotes mineral nucleation. These deposits serve as the primary target for non-invasive diagnostic imaging using bone-seeking radiopharmaceuticals like Technetium-99m pyrophosphate (PYP), which bind to the calcium with high affinity (Gillmore et al., 2016, Circulation). Although these deposits are not therapeutic targets for drug intervention, they are essential biomarkers that allow clinicians to differentiate ATTR-CA from other cardiomyopathies without the need for invasive endomyocardial biopsy (Hanna et al., 2020, JACC). Consequently, they play a pivotal role in the modern diagnostic algorithm and management of patients with suspected cardiac amyloidosis.

Other names

Myocardial microcalcificationsATTR-associated hydroxyapatite depositsCardiac amyloid calcificationCalcium-phosphate deposits in amyloidosis

Adsorption of bone-seeking phosphonate-based radiopharmaceuticals onto the surface of hydroxyapatite crystals within amyloid-infiltrated myocardial tissue (Schrutka et al., 2021, J. Clin. Med.).