Beneficial Effect of Pimobendan for Severe Heart Failure Due to Transthyretin Cardiac Amyloidosis

OBJECTIVE: Transthyretin amyloidosis, particularly wild-type transthyretin amyloid cardiomyopathy (ATTRwt), has been recognized as an important cause of morbidity and mortality in the aging population. However, it is difficult to manage heart failure itself in patients with cardiac amyloidosis. METHODS: We herein report the management of heart failure in an elderly patient with severe heart failure due to ATTRwt. We also review the clinical situation in an additional seven patients with cardiac amyloidosis who were administered pimobendan in our hospital. RESULTS: We treated a 71-year-old man with refractory heart failure due to ATTRwt. He was expected to be dependent on dobutamine infusion. We administered pimobendan and successfully improved his symptoms and hemodynamic status to allow his discharge from the hospital. An additional retrospective investigation observed that there were eight patients with ATTR amyloidosis who were administered pimobendan. Although all of the patients at the time of administration of pimobendan were NYHA class III or IV with repeated hospitalization for heart failure, pimobendan seemed to be effective for improving symptoms and enabling patients to be discharged and receive outpatient medical care. Furthermore, focusing on the changes in some biomarkers, we found that the brain natriuretic peptide and estimated glomerular filtration rate values improved after the administration of pimobendan in 5 consecutive patients for whom data were available without additional treatment (p=0.018 and 0.051, respectively). CONCLUSION: In clinical practice, pimobendan seems to have beneficial effects in heart failure management for improving physical activities and the quality of life in patients with transthyretin cardiac amyloidosis.