Outcomes in patients with light chain cardiac amyloidosis undergoing heart transplantation: a single centre UK study

Abstract Background Light chain cardiac amyloidosis (AL-CA) results in restrictive cardiomyopathy associated with progressive heart failure and poor survival. Traditionally, outcomes following heart transplantation in patients with AL-CA have been worse than in other heart failure cohorts and consequently, many centres do not offer this population transplantation. Purpose and Methods This was a retrospective observational study of 18 patients with AL-CA (age 52.7years +/- 8.3, male 66%) referred to our centre in the UK for assessment for heart transplantation from 2008 to 2023. Seven patients (39%) were listed for transplant, and all received orthotopic heart transplantation (OHT). This study compared pre-transplantation characteristics in those offered cardiac transplantation with those not transplanted. We also examined post-transplantation outcomes in this group (n=7) compared with the overall heart transplantation population (n=95) at our centre. Results Patients with AL-CA who were not offered transplantation (n=11) were older (mean age 54.3 vs 50.3 years), were more likely male (72% vs 57%) but had similar baseline renal function to those transplanted (median eGFR 60.4 vs 54.2ml/min). Reasons against offering OHT included extensive multisystem or renal amyloid deposition (n=4), insufficient haematological response (n=2), heart failure not advanced enough for OHT (n=1) and malignancy (n=1). Pre-transplant right heart catheterisation of patients undergoing OHT demonstrated a mean transpulmonary gradient of 7.8mmHg (+/- 1.9) and cardiac output of 2.94/min (+/- 0.3). Five patients (71%) had a complete and two (29%) a partial haematological response to clonally directed chemotherapy. Three patients were bridged to transplant with biventricular assist devices for 9, 10 and 51 days, respectively. Five patients developed episodes of histologically confirmed rejection of grade 2R that resolved with medical management. One patient experienced first degree atrioventricular block and had a pulseless electrical activity arrest 19 days after transplantation before being fitted with a permanent pacemaker. Two patients went on to receive autologous stem cell transplantation. Patients with AL-CA undergoing OHT had a lower mortality rate compared with non-transplanted patients over a median follow up of 9 months (HR 0.3, 95%CI 0.07-1.3, p = 0.10). Two patients with AL-CA died at 42 days and 7.7 years after OHT. Five patients (71%) are alive under follow up at 4, 7.5, 9, 10 months and 7.7 years post OHT. There was no difference in survival between patients who underwent heart transplantation for AL-CA and patients who underwent heart transplantation for all other indications (HR 1.94, 95%CI 0.3 – 12, p=0.45). Conclusions In selected patients with AL-CA, OHT offers favourable outcomes. After clonally directed therapy to control the underlying plasma cell dyscrasia, heart transplantation should be considered in the absence of widespread systemic disease.