Improving contemporary outcomes following heart transplantation for cardiac amyloidosis

The Cardiac Amyloidosis Registry Study (CARS): Rationale, Design and Methodology

BACKGROUND

CARS (Cardiac Amyloidosis Registry Study) is a multicenter registry established in 2019 that includes patients with transthyretin (ATTR, wild-type and variant) and light chain (AL) cardiac amyloidosis (CA) evaluated at major amyloidosis centers between 1997 and 2025. CARS aims to describe the natural history of CA with attention to clinical and diagnostic variables at the time of diagnosis, real-world treatment patterns, and associated outcomes of patients in a diverse cohort that is more representative of the at-risk population than that described in CA clinical trials.

METHODS AND RESULTS

This article describes the design and methodology of CARS, including procedures for data collection and preliminary results. As of February 2023, 20 centers in the United States enrolled 1415 patients, including 1155 (82%) with ATTR and 260 (18%) with AL CA. Among those with ATTR, wild-type is the most common ATTR (71%), and most of the 305 patients with variant ATTR have the p.V142I mutation (68%). A quarter of the total population identifies as Black. More individuals with AL are female (39%) compared to those with ATTR (13%).

CONCLUSIONS

CARS will answer crucial clinical questions about CA natural history and permit comparison of different therapeutics not possible through current clinical trials. Future international collaboration will further strengthen the validity of observations of this increasingly recognized condition.

Outcomes of heart transplantation in cardiac amyloidosis: an updated systematic review

Cardiac amyloidosis is one of the most common infiltrative cardiomyopathies that is characterized by the extracellular deposition of misfolded fibrillar protein. Several studies have previously found that patients with amyloid in the past have performed poorly after heart transplantation. Recent advancements in treatments have been made that have significantly improved outcomes in these patients. The study aimed to evaluate the outcomes of heart transplantation in cardiac amyloidosis. We systematically searched EMBASE, PubMed/MEDLINE, and Cochrane Library databases on 30 December 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We identified 22 studies that examined 42,951 patients with cardiac amyloidosis of which only 1,329 patients underwent isolated heart transplantation. Seven studies reported individual patient data. The results of 123 patients have been pooled for analysis. There were 70 male patients, 45 female patients, and eight patients who did not report their gender. Among the types of amyloids, 63 (51%) patients were found to have light chain amyloidosis (AL) and 33 (27%) patients had transthyretin amyloidosis (ATTR). Only 41 patients (33.3%) reported a monoclonal component. There were 30 patients with AL that underwent autologous hematopoietic stem cell transplant (ASCT). The mean survival of 24 out of 30 patients was 4.33 years. In addition, the reported data include 13 patients requiring intra-aortic balloon pump (IABP), six with cardiac resynchronization therapy (CRT), and four with implantable cardioverter defibrillator (ICD). With the current advancements in treatments in combination with a multidisciplinary approach and careful patient selection, patients undergoing heart transplantation for amyloidosis may have encouraging results in the current era. Further studies will be needed to evaluate the outcomes of heart transplantation in amyloidosis patients now that several advances have been made in the field.