The Impact of Era and Technical Improvements on a High Volume Minimally Invasive Mitral Valve Surgery Program
Nikolaos Bonaros, Daniel Hoefer, Johannes Holfeld, Can Gollmann-Tepeköylü, Cenk Oezpeker, Elfriede Ruttmann, Lukas Stastny, Michael Grimm, Ludwig Mueller
Innsbruck Medical University, Innsbruck, Austria
BACKGROUND: The aim of the study was to identify the impact of era and technical improvements on perioperative outcome after minimally invasive mitral valve surgery (MIMVS).
METHODS: We retrospectively investigated 1000 patients (mean age: 60.8±12.7y, 60.3% male) who underwent minimally invasive or endoscopic mitral valve surgery between 2001-2020 in a single institution. The patients were allocated to 4 groups according to the case number quartiles. Periprocedural success, safety and operative times were identified as outcome parameters. Operative success was defined as: Successful primary mitral repair without conversion to replacement, or larger thoracic incisions, no residual MR>mild at intraoperative TEE, and no need for reoperation within 30d. The definition of safety included: freedom from perioperative (30d) death, myocardial infarction, stroke, use of ECMO or reoperation for bleeding. Three technical interventions were introduced during the observed period of 19 years: (1) the introduction of a fully endoscopic technique through 3D visualization, (2) the adoption of pre-measured loops of neochordae for prolapse correction and (3) the implementation of a preoperative CT scan to exclude unsuitable candidates for MIMVS. Comparisons were made between the 4 quartiles and before and after the introduction of technical improvements by chi-square test and one-way ANOVA. RESULTS:
Perioperative survival, periprocedural success and safety were 99.1%, 93.5% and 96.3% respectively. There was a significant improvement in the combined periprocedural safety endpoint within the different eras mainly attributed to the lower need for ECMO support (p=0.036) and less reoperations for bleeding (p=0.007). On the other hand, the influence of era according to the different quartiles on periprocedural success was not statistically significant (p=0.590). The impact of technical improvements was thoroughly investigated in 897/1000 patients who underwent mitral valve repair on an intent to treat basis. The implementation of endoscopic techniques through 3D visualization had a significant impact on periprocedural success but not on safety. All three improvements led to decreased cardiopulmonary bypass and cross-clamp times in this patients cohort (s. Table 1). CONCLUSIONS:
Increased surgical experience improves safety in MIMVS. Technical improvements are related to increased operative success and decreased operative times in patients undergoing mitral repair.