LAUSR

Introduction No guidelines exist on the use of guideline-directed medical therapy (GDMT) in the setting of transthyretin cardiac amyloidosis (TTR CA) and HFrEF, and its use remains controversial. There is no survival data demonstrating the effects of beta blockers in patients with TTR CA, and the efficacy of angiotensin converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and angiotensin receptor-neprilysin inhibitors (ARNIs) are uncertain. This observational study describes the outcomes of patients with TTR CA and HFrEF treated with GDMT. Hypothesis We hypothesized that treatment with GDMT may not be harmful in select patients with TTR CA and HFrEF. Methods This observational case series included 8 consecutive patients with TTR CA and HFrEF treated with GDMT at a single institution. Medical records were retrospectively reviewed. Results The average age was 76.9±5.7 years and 75% were male. All-cause mortality was 50%. All patients were treated with a beta blocker, 75% were treated with either an ACEI, ARB, or ARNI, all were treated with a mineralocorticoid receptor antagonist, and all received diuretics. Fifty percent of patients (survivors) responded favorably to GDMT with improved EF (+Δ26.25 vs -Δ1.25%, p Conclusions While the natural history of TTR CA is poor, our study suggests that GDMT may be used cautiously and may not be harmful in patients with TTR CA and HFrEF; GDMT may be beneficial in select patients. Further observations and prospective studies are needed.