Background (Context):

Some older adults who undergo surgery to replace a narrowed heart valve (called aortic stenosis) may also have small protein deposits in their heart. These protein clumps, known as amyloid, are more often found in people with a certain condition called amyloidosis. However, in many cases, these deposits are found only in the upper chambers of the heart (called atria) and without any previous diagnosis of the disease. The meaning and health impact of these hidden amyloid deposits are still unclear.

Objectives (What the investigators wanted to find out):

This study aimed to understand how common these protein deposits are in people with aortic valve disease, what this deposits are made of, and how they affect recovery and health after heart surgery. To do this, various types of analysis were combined, including tissue samples, blood tests, and advanced genetic studies.

Methods (What the investigators did):

Seventy patients undergoing surgery to replace the aortic valve were studied. During the operation, small samples were collected from the top part of the heart and analyzed in the lab using special dyes and microscopes. Substances in blood were also measured, and health status was monitored over the following year. For some samples, advanced genetic tools were used to investigate processes at the level of individual cells.

The study aims to find out whether deposits of amyloid (an abnormal protein that builds up in tissues) in the upper chambers of the heart are linked to worse recovery after aortic valve replacement surgery. For example, it looks at whether these deposits are related to hospital readmissions, irregular heart rhythms, or problems with kidney function after surgery.

Inclusion Criteria:

• Over 18 years of age.
• Signed specific informed consent (see attached).
• Severe aortic stenosis with surgical indication.
• Elective isolated aortic valve replacement surgery via full or partial median sternotomy.

Exclusion Criteria:

• Urgent or emergency surgery (patients in cardiogenic shock, under intra-aortic balloon pump therapy or any other mechanical support, or receiving vasoactive drugs).
• Combined surgery with any additional procedure.
• Ischemic heart disease with significant lesions confirmed by preoperative invasive catheterization, with or without concomitant revascularization during aortic valve replacement surgery.
• Concomitant endocarditis.
• Inability to collect surgical tissue samples. Initially, all patients with at least one histological sample were included; later, only those with both atrial and septal samples were analyzed.
• Extracardiac disease with a life expectancy of less than 365 days.
• Patient with a previous and/or current diagnosis of any form of amyloidosis.
• Surgical access other than full or partial median sternotomy.
• Patients with severe aortic stenosis but with a TAVI indication as decided by a multidisciplinary heart team (including interventional cardiology, clinical cardiology, and cardiac surgery).

The study cohort includes consecutive patients who underwent isolated aortic valve replacement at Germans Trias i Pujol Hospital, and who met the inclusion criteria.