Key result
Positive 99mTc-PYP uptake is associated with worse LV global longitudinal strain.
Why the study?
There are limited data on the head-to-head comparison of 99mTc-pyrophosphate and echocardiographic strain imaging in transthyretin cardiac amyloidosis assessment.
Observational (n=64)
No
Absolute Event Rate: -10.5% vs -13.1%
p-value: p=0.003
PYP positivity linked to worse global/basal strain and diastolic dysfunction; extends observational correlation with echo strain but leaves clinical adoption open.
There are limited data on the head-to-head comparison of 99mTc-pyrophosphate (99mTc-PYP) and echocardiographic strain imaging in the assessment of transthyretin (TTR) cardiac amyloidosis. Methods: At Mayo Clinic Arizona, patients who had undergone both a 99mTc-PYP scan and a transthoracic echocardiogram within a 90-d period were retrospectively identified for chart review and strain imaging analysis. Patients were divided into 2 groups according to their 99mTc-PYP results (PYP-positive [PYP+] or PYP-negative [PYP−]) for the comparison. A standard 17-segment model was used for segmental, regional, and global longitudinal strain comparison. A P value of less than 0.05 was deemed significant. Results: In total, 64 patients were included, the mean age was 75.1 ± 13.0 y, and 57 (89.1%) were male. Comparing the PYP+ to the PYP− group, the left ventricular global longitudinal strain was significantly worse in the former (PYP+ vs. PYP−, −10.5 ± 2.6 vs. −13.1 ± 4.1; P = 0.003). PYP+ patients also had worse regional basal strain (−4.6 ± 2.6 vs. −8.8 ± 4.0, P < 0.001) and a trend toward worse midventricular strain (−9.6 ± 4.0 vs. −11.7 ± 4.4, P = 0.07), but there was no statistical difference in the apical region (−17.6 ± 4.73 vs. −19.0 ± 6.46, P = 0.35). This is consistent with an apex-sparing pattern shown by the relative apical longitudinal strain index (1.3 ± 0.5 vs. 1.0 ± 0.3, P = 0.008). Segment-to-segment analysis demonstrated a significant difference in strain between PYP+ and PYP− segments in 4 segments: basal inferior (P = 0.006), basal anterolateral (P = 0.01), apical septal (P = 0.002), and apical inferior (P = 0.001). Left ventricular diastolic dysfunction was significantly different, with 17 (77.3%) patients in the PYP+ group versus 15 (36.6%) in PYP− participants (P = 0.002). Conclusion: Our study suggested that 99mTc-PYP uptake is related to overall worse LV segmental, regional, and global longitudinal strain function, as well as diastolic function, compared with patients without 99mTc-PYP uptake. These data are important for helping clinicians learn about the echocardiographic function features related to 99mTc-PYP uptake and can help generate hypotheses for future studies.
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Lee et al. (2021) conducted an observational in Transthyretin (TTR) cardiac amyloidosis (n=64). 99mTc-PYP positive uptake vs. 99mTc-PYP negative uptake was evaluated on Left ventricular global longitudinal strain (p=0.003). Positive 99mTc-PYP uptake was associated with significantly worse left ventricular global longitudinal strain compared to negative uptake (-10.5 vs. -13.1; P=0.003).
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