Study Population and Cohort Design
Using convenient sampling method, we retrospectively analyzed clinical, hemodynamic, and echo-cardiographic data of consecutive 893 patients who underwent MVR between 2005 and 2015 at the Second Affiliated Hospital of Harbin Medical University were involved between2005 and 2015. The patients’ cardiologists and cardiac surgeons individually made the decision to undergo either surgical intervention or medical management. For study inclusion, patients who underwent MVR must have met the following criteria: 1) ≥18 years, 2) mild/moderate FTR, 3) MVR conducted by the first cardiac surgeon visited, and 4) available complete data. Criteria for patient exclusion were: 1) existing congenital heart disease, myocardiopathies, infective endocarditis, or organic TV disease with inadequate pulmonary artery systemic pressure (PASP), 2) no additional cardiac surgery received during the follow-up period, 3) had symptoms of right heart failure(RHF), and 4) incomplete follow-up data. Of course, they did have at least one measures of FTR every year during the five years of follow-up. FTR were measured at any of these time points if they subsequent visited at any point between the current time point and the prior pre-specified time point. At the same time, the sample size was estimated, and weighing the requirement that the group development model sample size should be 300-500 cases to ensure the model stability according to the logical proportional risk regression model. Based on these criteria, the study ultimately examined 378 patients (Figure. 1). The average number of examinations was 8.7, and the average time interval between examinations was one year during the whole follow-up period.