Mitral valve disease in ankylosing spondylitis: an autoimmune disease manifestation? A case report.

Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease of primarily the joints of the spine. In the literature, AS is known to have cardiac manifestations. Most frequently, this is aortic regurgitation. However, in rare cases also mitral valve (MV) disease is observed in AS patients. The extent and mechanism of this involvement are still unclear. We aim to describe a histologically validated case report to add understanding on this topic. Case summary: We show the case of a 51-year-old male who suffered since his youth from back pain and uveitis, which was later diagnosed as AS. After a first presentation with combined heart valve disease, the patient recovered on cardiac medical therapy and biologic treatment for AS. Four years later, cardiac complaints worsened mainly due to severe MV stenosis. Surgical treatment was performed with histopathologic analysis of the excised MV validating involvement of AS. Discussion: Histopathologic analysis showed chronic fibro inflammatory thickening of the MV leaflets and subvalvular apparatus. These pathological features could fit with the inflammatory nature of AS. Since this is a rare case, the recognition of fibro inflammatory thickening leading to commissural fusion and stenosis may contribute to better understanding of heart valve disease in AS to create a base for better cardiac management in this specific patient group.