A Study to Evaluate Vutrisiran in Patients With Transthyretin Amyloidosis With Cardiomyopathy

Change from Baseline in the Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS)

The KCCQ is a 23-item self-administered questionnaire quantifying 6 domains (symptoms, physical function, quality of life, social limitation, self-efficacy, and symptom stability) and 2 summary scores (clinical and overall summary \[OS\]). Scores are transformed to a range of 0-100, in which higher scores reflect better health status.

Time frame: Baseline up to 36 Months

Change from Baseline in New York Heart Association (NYHA) Class

NYHA classification grades the severity of heart failure symptoms into the following stages: I (no symptoms; ordinary physical activity such as walking and climbing stairs does not cause fatigue or dyspnea), II (symptoms with ordinary physical activity; walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold weather, in wind or when under emotional stress causes undue fatigue or dyspnea), III (symptoms with less than ordinary physical activity; walking 1 to 2 blocks on the level and climbing more than 1 flight of stairs in normal conditions causes undue fatigue or dyspnea), IV (symptoms at rest; inability to carry on any physical activity without fatigue or dyspnea).

Time frame: Baseline up to 36 Months

Change From Baseline in the Cardiac Biomarker: N-terminal Prohormone of B-type Natriuretic Peptide (NT-proBNP)

NT-proBNP will be assessed through measurement of serum levels.

Time frame: Baseline up to 36 Months

Change From Baseline in the Cardiac Biomarker: Troponin I