To the editor

We have read with great interest the results of a nationwide cohort study by Rywik et al1 including 2601 patients with heart failure (HF) across the spectrum of left ventricular ejection fraction (LVEF). Interestingly, the relative frequency of aortic stenosis (AS) was significantly greater in patients with HF with preserved LVEF (HFpEF) than in those with mildly reduced and reduced LVEF (HFmrEF and HFrEF, respectively) (P <⁠0.001).1

It has been formerly demonstrated that up to 16% of patients with AS have concomitant transthyretin cardiac amyloidosis (ATTR-CA), while the latter is associated with a severe phenotype of AS.2 Of note, patients with both AS and ATTR-CA seem to have a significantly worse prognosis, with a 1-year mortality of 24.5%, if left untreated.3

According to the analysis presented by Rywik et al,1 the relative frequency of comorbidities such as renal failure and anemia was significantly or marginally nonsignificantly higher in patients with HFpEF than in those with HFrEF and HFmrEF. Based on the fact that anemia and renal failure are common features of amyloidosis,4 a reasonable question that might arise is whether the relative frequency of cardiac amyloidosis was also greater in patients with HFpEF, compared with individuals with HFrEF and HFmrEF, in the cohort analyzed by Rywik et al.1

We think that if relevant information is available, it would be of great interest and scientific value, as it would provide further insights into a relatively common comorbidity, especially in light of recent new treatment options, such as tafamidis.5 Identification of different phenotypes of amyloidosis in each HF subtype will guide both the diagnostic approach and appropriate, targeted treatment strategies.