This clinical trial is focused on studying a condition known as Transthyretin Amyloidosis with Cardiomyopathy, often referred to as ATTR Amyloidosis with Cardiomyopathy. This is a disease where abnormal proteins build up in the heart, affecting its function. The study will use a treatment called Vutrisiran, which is a solution for injection. Vutrisiran is also known by its code name ALN-TTRSC02. The purpose of the study is to gather information on the safety of Vutrisiran in patients who have this condition.

Participants in the study will receive Vutrisiran through an injection under the skin. The study will observe patients who are continuing their treatment with Vutrisiran or those who are switching from another medication called Patisiran. The study will last for a period of time, during which the safety of the treatment will be closely monitored. Patients will be asked to take vitamin A supplements as part of the study protocol.

The study will track how often any side effects occur and will also look at changes in heart-related health measures. These include changes in a questionnaire score that assesses heart failure symptoms, changes in heart function class, and levels of certain proteins in the blood that indicate heart stress. The study will also monitor overall survival and any heart-related hospital visits. The goal is to better understand how Vutrisiran affects patients with ATTR Amyloidosis with Cardiomyopathy over an extended period.