Risk-score performance for detecting transthyretin cardiac amyloidosis in severe aortic stenosis: a prospective cohort study

Introduction The coexistence of transthyretin cardiac amyloidosis (ATTR-CA) and severe aortic stenosis (AS) presents a diagnostic challenge. This study aimed to determine the prevalence of this dual pathology and to assess the effectiveness of diagnostic models in enhancing detection accuracy. Methods We conducted a prospective study of 104 consecutive patients with severe AS (aortic valve area <1 cm 2 ). Comprehensive evaluation included clinical and laboratory assessments, electrocardiography, transthoracic echocardiography, planar whole-body bone scintigraphy, and chest single-photon emission computed tomography/computed tomography using technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid tracer. Patients were grouped according to the presence of ATTR-CA, and the diagnostic utility of the RAISE score, its variations, and the T-AMYLO score was evaluated. Results Nineteen (18%) patients with AS also had ATTR-CA (ATTR-CA-AS). They were significantly older (82.6 ± 7.4 vs. 76 ± 6.9, p  < 0.001), more often had arrhythmic and conduction disorders (atrial fibrillation, implanted pacemakers), and had a reduced left ventricular ejection fraction (44.6% vs. 54.7%, p  = 0.03). Patients with ATTR-CA-AS more frequently presented with the low-gradient/low-flow phenotype of AS (73.7%, p  = 0.009). Both NT-proBNP and troponin levels were significantly higher in patients with ATTR-CA-AS (4174.0 vs. 1,238 pg/mL; p  < 0.001; and 59.6 vs. 23.3 ng/L, p  < 0.001, respectively). After a 6-month follow-up, a similar number of deaths occurred in both groups, and no surgical aortic valve replacement was performed in the ATTR-CA-AS population. The eRAISE model demonstrated the highest diagnostic accuracy (AUC=0.948). Conclusions ATTR-CA is commonly observed in patients with severe AS. Implementing risk scores in routine practice could enhance the diagnostic accuracy of ATTR-CA in patients with AS, given their strong diagnostic performance and ease of assessment.