Long-Term Follow-Up For Participants Of: Evaluation Of Outcomes Following Mitral Valve Repair/Replacement In SMR and Surgical Interventions For MMR Trials

This study is a continuation of two CTSN randomized trials --- the Severe Ischemic Mitral Regurgitation (SMR) Trial (NCT00807040) and the Moderate Ischemic Mitral regurgitation (MMR) Trial (NCT00806988) --- for the purpose of assessing the long-term outcomes of the index surgical therapies. Key clinical outcomes will be collected utilizing electronic medical records, patient and/or family input, public records, and healthcare- and vital status-related databases. Extended follow-up data will be obtained on up to 199 SMR and 270 MMR trial participants, who were alive at their 2-year follow-up evaluation. Patients will be followed for a minimum of 5 years and up to 10 years after randomization (the time of index surgical procedure). This follow-up data collection will be conducted by the Cardiothoracic Surgical Trials Network (CTSN) primarily utilizing the minimal PHI necessary to link data obtained from the MMR and SMR trials to other healthcare- and/or vital status-related databases.

Because the design of surgical trials for ischemic mitral regurgitation that would use mortality as a primary endpoint requires the enrollment of thousands of patients, the selected primary endpoint for the CTSN SMR and MMR trials was an echocardiographic measure of left ventricular remodeling. Secondary endpoints included, among others, survival, adverse events, readmissions and costs over a 2-year period. The SMR trial showed no difference in left ventricular reverse remodeling, but the rate of moderate or severe mitral regurgitation recurrence was significantly higher with mitral valve repair, resulting in more heart failure-related adverse events and cardiovascular admissions. Longer-term follow-up will be critical to assess whether this observed trend amongst SMR patients will continue and whether a survival difference will manifest over time. In moderate ischemic mitral regurgitation, mitral valve repair provided a more durable correction of mitral regurgitation than coronary artery bypass grafting (CABG) alone, but repair did not improve survival or reduce overall adverse events or readmissions, and was associated with an early hazard of neurological and supraventricular arrhythmic events. Longer-term follow-up of MMR patients will provide insights into whether the higher degree of recurrent mitral regurgitation with CABG alone will be associated with differences in adverse events, readmissions and survival. Additionally, the benefits of alternative surgical treatments for ischemic mitral regurgitation, which have differential upfront risks and costs, will likely extend beyond 2 years. Cost-effectiveness analysis will delineate the long-term cost-benefit trade-offs between mitral valve repair versus replacement for SMR, and of CABG with repair versus CABG alone for MMR, which should inform surgical decision making, and examine how differences in life expectancy and risk profiles of different patient groups affect cost-effectiveness over time. This extended follow-up should provide important clinical and health policy insights.