Background:Although mitral valve repair is recommended over replacement due to better outcomes, repair rates vary significantly among centers. This study examined the effect of institutional mitral valve repair volume on postoperative mortality.

Methods and Results:All cases of adult mitral valve repair performed in Korea between 2009 and 2016 were analyzed. The association between case volume and 1-year mortality was analyzed after categorizing centers according to the number of mitral valve repairs performed as low-, medium-, or high-volume centers (<20, 20–40, and >40 cases/year, respectively). The effect of case volume on cumulative all-cause mortality was also assessed. In all, 6,041 mitral valve repairs were performed in 86 centers. The 1-year mortality in low-, medium-, and high-volume centers was 10.1%, 8.7%, and 4.7%, respectively. Low- and medium-volume centers had increased risk of 1-year mortality compared with high-volume centers, with odds ratios of 2.80 (95% confidence interval [CI] 2.15–3.64; P<0.001) and 2.66 (95% CI 1.94–3.64; P<0.001), respectively. The risk of cumulative all-cause mortality was also worse in low- and medium-volume centers, with hazard ratios of 1.96 (95% CI 1.68–2.29; P<0.001) and 1.77 (95% CI 1.47–2.12; P<0.001), respectively.

Conclusions:Lower institutional case volume was associated with higher mortality after mitral valve repair. A minimum volume standard may be required for hospitals performing mitral valve repair to guarantee adequate outcome.

背景：尽管由于更好的结果，推荐二尖瓣修复而不是置换，但各中心的修复率差异很大。本研究考察了机构二尖瓣修复量对术后死亡率的影响。

方法和结果：分析了 2009 年至 2016 年在韩国进行的所有成人二尖瓣修复病例。根据作为低、中或高容量中心（<20、20–40 和 >40 例/年）进行二尖瓣修复的数量对中心进行分类后，分析病例数与 1 年死亡率之间的关联， 分别）。还评估了病例数对累积全因死亡率的影响。总共在 86 个中心进行了 6,041 次二尖瓣修复。低、中和高容量中心的 1 年死亡率分别为 10.1%、8.7% 和 4.7%。与大容量中心相比，低容量和中等容量中心的 1 年死亡率风险增加，优势比为 2.80（95% 置信区间 [CI] 2.15-3.64；P<0.001）和 2.66（95% CI 1.94） –3.64；P<0.001)，分别。

结论：机构病例数越少，二尖瓣修复术后死亡率越高。进行二尖瓣修复的医院可能需要最低容量标准，以保证足够的结果。