Key result
A myocardial PYP H/CL ratio ≥1.25 or positive PYP SPECT independently predicted higher risk of cardiac death or fatal arrhythmias in suspected ATTR-CA patients.
Why the study?
99mTc-pyrophosphate (PYP) imaging is widely used for noninvasive diagnosis of transthyretin cardiac amyloidosis, but its prognostic significance remains unclear.
Does significant myocardial PYP uptake predict cardiac death or fatal ventricular arrhythmias in patients with suspected ATTR-CA?
Does significant myocardial PYP uptake predict cardiac death or fatal ventricular arrhythmias in patients with suspected ATTR-CA?
In patients with suspected ATTR-CA, significant myocardial PYP uptake is independently associated with an increased risk of cardiac death and fatal ventricular arrhythmias, suggesting utility for risk stratification.
Supports risk stratification in suspected ATTR-CA; leaves open whether PYP positivity should alter management.
Background Transthyretin cardiac amyloidosis (ATTR-CA) is increasingly recognized as a major cause of heart failure, particularly in elderly patients. 99mTc-pyrophosphate (PYP) imaging is widely used as a noninvasive diagnostic tool; however, its prognostic significance remains unclear. Furthermore, myocardial PYP uptake has been documented in other cardiomyopathies, including Amyloid light-chain amyloidosis, hypertrophic cardiomyopathy, and high-risk coronary artery disease. The present study aimed to evaluate the prognostic value of myocardial PYP uptake in patients with suspected ATTR-CA. Methods A retrospective cohort study was conducted on 301 consecutive patients who underwent PYP imaging for suspected ATTR-CA from July 2015 to February 2023. Myocardial PYP uptake was assessed using the Perugini classification (grades 0–3) and the heart-to-contralateral lung (H/CL) ratio. The primary outcome was a composite of cardiac death or fatal ventricular arrhythmias, including ventricular fibrillation (VF) and sustained ventricular tachycardia (VT). Prognostic significance was evaluated using Kaplan-Meier analysis and Cox proportional hazards regression. Results The median H/CL ratio at 3 hours was 1.25 (interquartile range, 1.16–1.40), and 90 patients (30%) exhibited positive PYP uptake. During a median follow-up of 660 days (interquartile range, 183–863 days), 36 patients (12.0%) died, including 13 cardiac deaths (4.3%). Furthermore, fatal ventricular arrhythmias were documented in six patients, including two cases of aborted VF and four instances of sustained VT. Kaplan-Meier analysis revealed that patients with an H/CL ratio ≥1.25 exhibited a significantly higher incidence of the primary outcome compared to those with a lower ratio (P=0.003). Similarly, patients with positive PYP SPECT at 3 hours also demonstrated a significantly higher incidence of the primary outcome (P=0.017). Conversely, all-cause mortality did not exhibit a significant difference between the various H/CL ratio groups (P=0.065) or the PYP SPECT positivity groups (P=0.36). Multivariable Cox proportional hazards regression analysis demonstrated that both a higher H/CL ratio (P=0.018) and PYP SPECT positivity (P=0.007) were independent predictors of the primary outcome and cardiac death in patients with suspected ATTR-CA. Conclusions Significant myocardial PYP uptake was associated with an increased risk of adverse cardiovascular events in patients with suspected ATTR-CA. The findings of this study suggest that PYP imaging may be useful not only for diagnosing ATTR-CA but also for risk stratification in patients with suspected ATTR-CA, including those with other cardiomyopathies.primary endpoint(cardiac death or VT/VF) All-cause death
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Ajima et al. (2025) studied this question. A myocardial PYP H/CL ratio ≥1.25 or positive PYP SPECT independently predicted higher risk of cardiac death or fatal arrhythmias in suspected ATTR-CA patients.
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