Freedom from reoperation is approxi- mately 80%, and freedom from recurrent moderate or severe MR is 60% at 15 to 20 years in complex cases. These results are superior to the results of mitral valve re- placement if the repair is performed at high-volume valve even in elderly patients.30,31 Repair should also be attempted, if possible, with other causes of severe MR, such as papillary muscle rupture, IE, and cleft mitral valve. However, the results of very complex repair in younger patients may be matched by the re- sults of durable mechanical mitral valve replacement with careful management of anticoagulation. The Heart Valve Team should assign complex repairs to experienced mitral valve surgeons with established excellent operative and long-term outcomes. The probability of mitral valve repair rather than mitral valve replacement and overall outcome correlate with surgeon-specific mitral volumes.21,27 The hospital mortality rate is 50% lower, on average, in the highest-volume hospitals that perform 50 repairs per year. However, some low-volume hospitals outperform the median high-volume hospitals. This overlap suggests that hospital- or surgeon-specific volumes should not be used as a surrogate for actual surgeon-specific repair rates and outcomes (Figure 8). The management of patients with combined severe primary MR and AS is discussed in the Mixed Valve Disease section (Section 10.2.2). Recommendation-Specific Supportive Text 1. Primary MR is a mechanical problem of the leaflet coaptation that has only a mechanical solution that of mitral valve mechanical intervention. The onset of symptoms that results from severe MR worsens prognosis even when LV function appears to be normal,1,2 and the negative prognosis extends even to mild symptoms.2 Thus, the onset of symp- toms is an indication for prompt mitral valve surgery. 2. 