The study is designed to test the **GORE® Ascending Stent Graft (ASG)** for treating a serious heart condition called **Type A aortic dissection**. This happens when there's a tear in the wall of the main artery, the aorta, near the heart. The study aims to see if this device can safely and effectively help patients who are too high-risk for regular surgery. To participate, patients must have the dissection within 30 or 90 days from symptom onset, depending on the study arm. The study involves placing the ASG device in the aorta to help fix the tear. **Key Points:** - **Study Length & Follow-Up**: Participants need to agree to a 5-year follow-up with regular imaging checks. - **Eligibility**: Must be 18 or older, with specific heart conditions, and not have certain health issues like active infections or other severe conditions. - **Risks & Procedures**: The procedure is less invasive than open surgery, but participants must not have allergies to device materials or specific medical conditions. This study may offer an alternative to open surgery for those at high risk.