Minimally Invasive MVR With Degenerative Mitral Regurgitation
Our study demonstrates that MV repair through MIMVS is a safe and feasible procedure associated with excellent early and long-term follow-up. Specifically, overall mortality and stroke rate was 0.2% and 1.3%, respectively and survival at eight years was 90%. Moreover, the rate of MV repair at discharge was 95.3%, higher than data reported by the Society of Thoracic Surgeons (STS) database.. Finally, freedom from reoperation and mitral regurgitation were 92% and 90% at eight-year follow-up. These data are in line with previous studies, confirming that MIMVS may offer the same quality and safety of a conventional approach, guaranteeing high rate of MV repair, even in complex cases. Despite a number of studies showing at least equivalent surgical results compared with the conventional approach, traditionalists claim that MV repair through minithoracotomy is more complex and technically challenging, especially in the presence of Barlow's MV disease. As a result, MIMVS may reduce the rate of MV repair. However, a meta-analysis of 2,000 patients has shown satisfactory echocardiographic outcomes, and the incidence of moderate/severe mitral regurgitation was 0.1% in the MIMVS group and 0.3% in the conventional sternotomy group, respectively. Our data are in line with this study, reporting a rate of moderate mitral regurgitation of 0.1% at discharge. Furthermore, our long-term freedom from reoperation was 93%, confirming that this approach does not influence the outcome of MV repair. A second criticism concerns the learning curve required for both MV repair and minithoracotomy approach; however, a young surgeon should intuitively start approaching the MV repair through standard sternotomy, and progress toward less invasive techniques thereafter. In this setting, the learning curve requires two important steps, raising ethical concerns regarding the safety of patients and their outcomes. Recently, we investigated the operative outcomes of five young surgeons who were trained in MV repair directly through a minimally invasive approach, and a senior surgeon (MG) who introduced the technique and was responsible for the training program. Interestingly, we found no statistical difference in terms of mortality, morbidity and rate of MV repair, concluding that MIMVS repair is safe and reproducible technique that can be taught successfully to cardiac trainees. Similar results were achieved by the Leipzig group. Finally, according to a cross-sectional survey on MIMVS, Misfeld and colleagues concluded that more than 20 cases are required to gain familiarity with less invasive techniques. The third criticism concerns the increased risk of stroke associated with MIMVS; however, the stroke rate in our study (1.3%) was similar to those reported in the literature for conventional standard sternotomy. We recently demonstrated that antegrade perfusion with direct aortic cannulation reduces the risk of neurological events compared with peripheral cannulation, avoiding morbidities related to groin cannulation such as wound dehiscence and pseudoaneurysms.
Finally, for many surgeons, the decision to utilize MIMVS is more related to the cosmetic results than better clinical outcomes, because no large randomized trial has been performed. However, the chance to perform a well-designed randomized trial with appropriate sample size is difficult as MIMVS has guaranteed the same quality and safety of the standard approach, and patients now demand less invasive procedures, especially in well-known minimally invasive centers.
This study has several limitations. It is based on a retrospective analysis of patients undergoing consecutively MIMVS over the eight-year period and potential bias might be present. However, our database was filled in prospectively. Secondly, our database was not able to distinguish between Barlow MV disease and fibroelastic disease, and no information was reported on anterior or posterior leaflet disease. Thirdly, our echocardiographic follow-up was only completed by 70% of the patient population, which may have influenced results. Finally, because MIMVS is our first approach to treating MV disease, we were not able to perform a retrospective study comparing patients undergoing conventional surgery versus the minithoracotomy approach.
In conclusion, in the setting of degenerative MV regurgitation, our study demonstrates that MIMV repair through right minithoracotomy is a safe and reproducible procedure associated with high rate of MV repair, and excellent early postoperative and long-term results.
Discussion
Our study demonstrates that MV repair through MIMVS is a safe and feasible procedure associated with excellent early and long-term follow-up. Specifically, overall mortality and stroke rate was 0.2% and 1.3%, respectively and survival at eight years was 90%. Moreover, the rate of MV repair at discharge was 95.3%, higher than data reported by the Society of Thoracic Surgeons (STS) database.. Finally, freedom from reoperation and mitral regurgitation were 92% and 90% at eight-year follow-up. These data are in line with previous studies, confirming that MIMVS may offer the same quality and safety of a conventional approach, guaranteeing high rate of MV repair, even in complex cases. Despite a number of studies showing at least equivalent surgical results compared with the conventional approach, traditionalists claim that MV repair through minithoracotomy is more complex and technically challenging, especially in the presence of Barlow's MV disease. As a result, MIMVS may reduce the rate of MV repair. However, a meta-analysis of 2,000 patients has shown satisfactory echocardiographic outcomes, and the incidence of moderate/severe mitral regurgitation was 0.1% in the MIMVS group and 0.3% in the conventional sternotomy group, respectively. Our data are in line with this study, reporting a rate of moderate mitral regurgitation of 0.1% at discharge. Furthermore, our long-term freedom from reoperation was 93%, confirming that this approach does not influence the outcome of MV repair. A second criticism concerns the learning curve required for both MV repair and minithoracotomy approach; however, a young surgeon should intuitively start approaching the MV repair through standard sternotomy, and progress toward less invasive techniques thereafter. In this setting, the learning curve requires two important steps, raising ethical concerns regarding the safety of patients and their outcomes. Recently, we investigated the operative outcomes of five young surgeons who were trained in MV repair directly through a minimally invasive approach, and a senior surgeon (MG) who introduced the technique and was responsible for the training program. Interestingly, we found no statistical difference in terms of mortality, morbidity and rate of MV repair, concluding that MIMVS repair is safe and reproducible technique that can be taught successfully to cardiac trainees. Similar results were achieved by the Leipzig group. Finally, according to a cross-sectional survey on MIMVS, Misfeld and colleagues concluded that more than 20 cases are required to gain familiarity with less invasive techniques. The third criticism concerns the increased risk of stroke associated with MIMVS; however, the stroke rate in our study (1.3%) was similar to those reported in the literature for conventional standard sternotomy. We recently demonstrated that antegrade perfusion with direct aortic cannulation reduces the risk of neurological events compared with peripheral cannulation, avoiding morbidities related to groin cannulation such as wound dehiscence and pseudoaneurysms.
Finally, for many surgeons, the decision to utilize MIMVS is more related to the cosmetic results than better clinical outcomes, because no large randomized trial has been performed. However, the chance to perform a well-designed randomized trial with appropriate sample size is difficult as MIMVS has guaranteed the same quality and safety of the standard approach, and patients now demand less invasive procedures, especially in well-known minimally invasive centers.
This study has several limitations. It is based on a retrospective analysis of patients undergoing consecutively MIMVS over the eight-year period and potential bias might be present. However, our database was filled in prospectively. Secondly, our database was not able to distinguish between Barlow MV disease and fibroelastic disease, and no information was reported on anterior or posterior leaflet disease. Thirdly, our echocardiographic follow-up was only completed by 70% of the patient population, which may have influenced results. Finally, because MIMVS is our first approach to treating MV disease, we were not able to perform a retrospective study comparing patients undergoing conventional surgery versus the minithoracotomy approach.
In conclusion, in the setting of degenerative MV regurgitation, our study demonstrates that MIMV repair through right minithoracotomy is a safe and reproducible procedure associated with high rate of MV repair, and excellent early postoperative and long-term results.
SHARE
