Impact of Tafamidis on Sleep–disordered Breathing in Transthyretin Cardiac Amyloidosis

Background Heart failure (HF) is frequently associated with central apnea (CA) and obstructive apnea (OA), which often improve after treatment. Amyloid transthyretin (TTR) cardiomyopathy (ATTR–CM) is increasingly recognized as a cause of HF. Tafamidis, a TTR stabilizer, slows disease progression by preventing TTR misfolding and aggregation, reducing mortality, cardiovascular hospitalizations, and functional decline. Its potential effect on apnea burden in ATTR–CM remains unclear. Purpose To evaluate the impact of tafamidis on the apneic burden in patients with ATTR–CM and HF. Methods Consecutive ATTR–CM patients initiating tafamidis therapy underwent a 24–hour ambulatory cardiorespiratory monitoring to evaluate the prevalence and severity of breathing disorders at baseline and after 6 months. The severity of these disorders was quantified using the apnea–hypopnea index (AHI). Patients were categorized as having CA (AHI ›5/hour, ≥50% central), OA (AHI ≥5/hour, ›50% obstructive), or normal breathing (NB, AHI ‹5/hour). Results Ninety–six ATTR–CM patients (90% males, mean age 78±6 years) were enrolled. At baseline, 63% of patients had OA, and 30% had CA. After 6 months, 66% and 21% of patients presented with OA and CA, respectively. Then after the treatment, AHI remained unchanged over 24 hours (p=0.93), as well as during daytime (p=0.39), and nighttime (p=0.44), regardless of apnea type or baseline severity. When classifying patients according to the type of apneas, tafamidis treatment was not associated with significant changes in daytime, nighttime, or 24–hour AHI (Figure 1). Conclusions In a real–life cohort of ATTR–CM patients, 6–month treatment with tafamidis was associated with stabilization of apneic burden without differences between obstructive and central apnea, or between daytime and nighttime events.