Introduction: Cardiac amyloidosis is an infiltrative cardiomyopathy with high morbidity and mortality, frequently presenting as heart failure (HF) with preserved left ventricular ejection fraction (LVEF). In transthyretin cardiac amyloidosis (ATTR-CM), early recognition of clinical red flags is essential. Scintigraphy with 99mTc-labelled pyrophosphate (99mTc-PYP) is a key diagnostic tool. Tafamidis, a transthyretin stabiliser, has demonstrated efficacy in slowing disease progression.
Objective: To describe the clinical characteristics and outcomes of patients diagnosed with ATTR-CM by 99mTc-PYP scintigraphy, analysing the main diagnostic “red flags”, treatment decisions, and clinical evolution.
Methods: A retrospective analysis was conducted on 100 patients referred for 99mTc-PYP scintigraphy between January and October 2022 due to suspected ATTR-CM. Of the 30 positive scans, 29 were confirmed ATTR-CM (excluding one AL amyloidosis case). Clinical data and therapeutic decisions were assessed.
Results: Among the 29 confirmed cases (mean age 84 years; 26 male), prevalent comorbidities included hypertension (72%), chronic kidney disease (52%), dyslipidaemia (41%), and diabetes (21%). All tested negative for pathogenic TTR mutations.
Univariate analysis identified age >75, HF, and low voltage on ECG as significant ESC red flags (p<0.01). In multivariate analysis, age and low QRS voltage were independently associated with a higher likelihood of ATTR-CM.
Five patients (mean age 81.2, all male) received Tafamidis. At baseline, all were NYHA class II with a mean LVEF of 45%. After follow-up, four remained alive with stable symptoms; one died of a non-cardiac cause.
The remaining 24 patients (mean age 80.9) did not receive Tafamidis. Reasons for non-initiation included kidney disease (7), asymptomatic status (6), and advanced age (5). Other reasons were early death post-diagnosis (2), severe comorbidities (2), and clinical trial participation (1). At follow-up, 12 remained alive with stable NYHA class; 12 had died, one-third from cardiac causes.
Conclusion: In this cohort, 29% of patients with suspected ATTR-CM were confirmed via 99mTc-PYP scintigraphy. Early identification based on red flags was key to diagnosis. Only 17% received Tafamidis, with non-treatment mainly due to renal disease, absence of symptoms, or age. Treated patients showed better functional stability and lower mortality. These findings underscore the importance of early diagnosis and support the need for larger prospective studies.