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.
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.
Abstract 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
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.