National patterns in imaging utilization for diagnosis of cardiac amyloidosis: A focus on Tc99m-pyrophosphate scintigraphy.

BACKGROUND

Tc99m-pyrophosphate (Tc99m-PYP) scintigraphy has emerged as a diagnostic modality for transthyretin (TTR) cardiac amyloidosis (CA). We sought to examine the variability in test utilization across multiple centers in the US.

METHODS

An electronic, web-based survey addressing specifics on Tc-99m PYP imaging was emailed to ASNC members, totaling 2785 recipients. Only one response per institution was allowed.

RESULTS

Responses were collected from 101 centers between July 2 and July 27, 2015. Among the respondents, 24% performed Tc-99m PYP specifically for CA diagnosis. The most commonly used dose was 20 mCi (37%) and most centers (35%) imaged 1 hour after injection. Scans were most often interpreted by cardiologists (60%). Quantification of uptake was performed in 57% of institutions with almost half (43%) utilizing the heart-to-contralateral lung (H/CL) ratio.

CONCLUSIONS

This national survey shows relatively low penetrance and high variability in Tc99m-PYP scintigraphy for CA diagnosis highlighting the need for standardization.