Thoracic aortic aneurysms (TAA) result from progressive dilatation of the thoracic aorta and confer a risk for aortic dissection or rupture, which is associated with significant morbidity and mortality. In the Netherlands there are an estimated 200.000 adults with TAA, and annually 600 deaths after aortic dissection or rupture. There are clear differences in the incidence of TAA between men and women, with a higher incidence in men. Little is known on possible differences in outcome between male and female patients with Thoracic Aortic Aneurysm (TAA). Aortic disease is thought to affect men more frequently than women, and aortic growth is different between men and women. Current data suggest that women are at an increased risk of both dying from aortic dissection and having aorta-related complications compared to men (1). The mechanisms for these male-female difference in TAA outcome remain, however, unclear. The timing of preventive surgery is now not different for men and women, but gender-based cut-off values for maximal aortic diameter based on differences in vessel wall composition might be needed.

Thoracic aortic aneurysms (TAA) result from progressive dilatation of the thoracic aorta and confer a risk for aortic dissection or rupture, which is associated with significant morbidity and mortality. In the Netherlands there are an estimated 200.000 adults with TAA, and annually 600 deaths after aortic dissection or rupture. There are clear differences in the incidence of TAA between men and women, with a higher incidence in men. Little is known on possible differences in outcome between male and female patients with Thoracic Aortic Aneurysm (TAA). Aortic disease is thought to affect men more frequently than women, and aortic growth is different between men and women. Current data suggest that women are at an increased risk of both dying from aortic dissection and having aorta-related complications compared to men(1). However, the mechanisms for these male-female differences in TAA outcome remain unclear. The timing of preventive surgery is not different for men and women, but gender-based cut-off values for maximal aortic diameter based on differences in vessel wall composition might be beneficial for outcome.

The current research project aims to implement male-female specific insights into aortic root and ascending aorta characteristics into clinical practice, allowing better identification of high risk Thoracic Aortic Aneurysm (TAA) patients and better timing of intervention. With this study the investigators aim to obtain insight into male-female differences in the immunohistological and biomechanical properties of the thoracic aortic wall. In order to reveal possible mechanisms for male-female differences in TAA.

Inclusion Criteria:

• Adult patients (≥ 18 years old) who have a thoracic aortic aneurysm and are scheduled for elective thoracic aortic surgery in the Erasmus MC or the LUMC.

Exclusion Criteria:

• Patients with a known connective tissue disease (e.g. Marfan Syndrome and Ehlers-Danlos syndromes).
• Connective tissue disease,

Adults (≥18 years old) who will undergo or already underwent elective surgery for thoracic aortic aneurysm at Erasmus MC, Rotterdam and LUMC, Leiden.

All our anonymised individual patient data (IPD) will be available to other researchers, upon reasonable request and after publication of the manuscript. This includes IPD derived from all analyses that were performed for and used in this study.

Data will become available upon request after a period of twelve months from the date of publication. The length of availability of IPD will depend on and therefore be based on the request of the researchers.

IPD will be shared with scientific researchers and is dependent on the research questions. The analysis and interpretation by the researcher will be checked by the project leader before any submission of the manuscript.