Long-term outcomes in patients with dual pathology aortic stenosis and cardiac amyloidosis referred for valve intervention

Background The coexistence of aortic stenosis (AS) and cardiac amyloidosis (CA) is common. If treated with transcatheter aortic valve implantation (TAVI), patients with the combined phenotype (AS-CA) have a comparable short term survival to those with lone AS, whereas data on longer term outcomes is currently lacking. Purpose This study aimed to evaluate the clinical outcomes of AS-CA compared to lone AS over a 5-year follow-up. Methods Using a prospective, multicentre, observational, case-control design, we screened consecutive patients with severe AS referred for TAVI for co-existing CA. CA screening included blinded 99mTc-DPD bone scintigraphy (Perugini Grade-0 negative, 1-3 increasingly positive) with additional SPECT/CT and light chain assessment prior to intervention. Transthyretin CA (ATTR) was diagnosed by bone scintigraphy and unremarkable light chain assessment, light-chain CA (AL) by endomyocardial biopsy. Mortality (all-cause and cardiovascular [CV]) and hospitalisation for heart failure (HHF) were captured as clinical endpoints. Results 376 patients (83±7 years, 52% female, EuroSCORE-II 4.9±2.9) were recruited, of which 43 (11.4%) had AS-CA (42 ATTR, 1 AL). Compared to lone AS, patients with AS-CA were older with higher cardiac biomarkers (NT-proBNP, high-sensitive Troponin-T) and a higher prevalence of atrial fibrillation. Heart team decision yielded valve replacement in 320 (85%) and conservative management in 56 (15%) patients, without differences between AS-CA and lone AS. Over a median follow-up of 5.4 (Q1: 4.9; Q3: 5.7) years, 230 (61.1%) patients died and 67 (17.8%) experienced HHF (with a total HHF number of 91). AS-CA was associated with higher all-cause mortality (crude HR 1.64, 95%CI 1.15-2.35; log-rank, p=0.006), which remained significant after multivariate adjustment for clinical confounders (EuroSCORE-II, valve replacement; adjusted HR 1.63, 95%CI 1.15-2.32; p=0.006). AS-CA was not associated with CV mortality (log-rank, p=0.18) or time to first HHF (log-rank, p=0.43), but the rate of HHF was significantly higher in AS-CA compared to lone AS (5.7 versus 3.5 per 1,000 patient years, p=0.022). Conclusions Among elderly patients referred for TAVI, long-term outcomes of AS-CA are characterized by higher mortality and a higher rate of heart failure hospitalisations compared to patients with lone AS. Studies evaluating the role of CA-specific treatments are warranted in this population.