Clinical challenges in calcific mitral stenosis from diagnosis to management

The prevalence of calcific mitral stenosis (MS), which is associated with mitral annular calcification (MAC), has been increasing, particularly in aging populations such as in Japan. Severe MAC interferes with the normal diastolic relaxation of the mitral annulus, and calcification can extend onto the mitral leaflets with reduced leaflet mobility, causing MS. As MAC frequently coexists with aortic stenosis, aortic stenosis is a strong risk factor for calcific MS among patients with MAC. The advent and expansion of transcatheter aortic valve implantation revealed attendant challenges of calcific MS. The diagnosis and severity assessment of calcific MS differ from rheumatic MS. Further, the combination of aortic and mitral stenoses complicates the hemodynamic assessment. Calcific MS is frequently observed in elderly patients with multiple comorbidities; therefore the prognosis of calcific MS is influenced by these comorbidities as well as the patient's general condition. Surgical mitral valve replacement is considered an optimal treatment for MS. However, severe MAC poses significant challenges for surgeons, often requiring debridement, decalcification, and annular reconstruction, which lead to an increased surgical risk. Because perioperative mortality can be high in these patients undergoing high-risk cardiac surgery, medical therapy is preferred, and less invasive surgical procedures or catheter interventions are considered. This review integrates the latest insights into the pathophysiology, diagnosis, prognosis, and treatment options of calcific MS, highlighting its clinical challenges.