Elucidating associations between technetium pyrophosphate scintigraphy, echocardiography and cardiac biomarkers in transthyretin cardiac amyloidosis
Bibliographic record
Abstract
Background Transthyretin amyloidosis is an under-recognised systemic disease whereby misfolded transthyretin proteins form fibrils capable of depositing in various tissues and organs. Despite improvements to diagnostic modalities, the associations between imaging techniques and clinical laboratory metrics remain unclear. Methods A single-centre retrospective cohort study was performed including 183 patients aged 18 years or older diagnosed with transthyretin cardiac amyloidosis (ATTR-CA) in a tertiary care setting. Linear regression and multivariate proportional hazard models were used to examine the associations between established imaging modalities (ie, technetium-99m pyrophosphate ( 99m Tc-PYP) scintigraphy and echocardiography) and cardiac biomarkers (ie, cardiac troponin I and B-type natriuretic peptide (BNP)). The study included patients who visited the Toronto General Hospital Peter Munk Cardiac Centre between October 2012 and December 2022. Results Of the 183 patients included, 143 (78.1%) were male, with a median age (IQR) of 73.0 (66.0–79.0) years. Primary analyses revealed significant associations between positive 99m Tc-PYP grading and echocardiographic parameters, particularly increased left ventricular (LV) mass (β=111.21, p=0.009) and greater interventricular septal thickness at end-diastole (IVSd) (β=0.48, p=0.003) in patients with hereditary transthyretin amyloidosis (ATTRm). Additionally, positive 99m Tc-PYP grades correlated significantly with cardiac biomarkers, including log-transformed BNP (logBNP; β=1.99, p=0.002) in patients with ATTRm and log-transformed Troponin (logTroponin; β=1.68, p=0.007) in patients with wild type ATTR (ATTRwt). Conversely, the heart-to-contralateral lung ratio, a quantitative index derived from 99m Tc-PYP scintigraphy, did not show significant correlations with cardiac biomarkers (logBNP and logTroponin), but demonstrated significant associations with LV mass (β=134.52, p=0.001) and IVSd (β=0.46, p=0.002) in patients with ATTRm. Conclusions These data suggest strong associations exist between cardiac biomarkers, structural echocardiographic changes and 99m Tc-PYP scintigraphy, emphasising the importance of a multipronged diagnostic approach stratified by genotype.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".