胸部外科

In the era of M-clip, surgery for ischemic/functional mitral regurgitation（ FMR） which is a ventricular disease remains a challenge. We try to do ventricular treatment as much as possible. We reviewed 11 patients（ 9 males, 63±12 years old） who had “dual repair” surgery which consists of anterior relocation of both papillary heads/muscles and simplified ventricular restoration （frozen-apex restoration）. There was 1 hospital death of mesenteric ischemia in a 80 years old patient with sarcoidosis and chronic kidney disease（CKD）. FMR changed from 2.7±0.9 preoperatively to 0.9±0.5（ p<0.001） postoperatively. Similarly, New York Heart Association （NYHA） class from 3.7±0.8 to 1.8±0.6 （p<0.001）, left ventricular end-diastolic dimension （LVDd） from 72±12 to 67±12 mm （p＜0.01）, end-systolic dimension （Ds） from 65±12 to 59±14 mm （p＜0.01）, ejection fraction （EF） from 23±8 to 28±10 （p=0.04）, and right ventricular pressure（ RVP） from 38±13 to 31±8 mmHg. There was no late death with the follow-up of 20±15 months （range 2～42 months）. In conclusion, ventricular treatment by “dual repair” surgery helps patients with FMR. Surgery may be a good compensatory treatment for catheter intervention.

Functional mitral stenosis after mitral valve repair for degenerative mitral regurgitation（ DMR） is an evolving concept. Mitral annuloplasty devices stabilize the mitral annulus, reduce leaflet stress and increase leaflet coaptation, which leads to improvement of repair durability at the cost of dynamic and physiological annular movement and diastolic annular area. An elevation in rest and peak transmitral gradient has been observed in some patients with annuloplasty devices, and this elevation may associate with worse prognosis as late atrial fibrillation or lower functional capacity after surgery. In this review, we summarize the current reports describing functional mitral stenosis after mitral valve repair for DMR.

Background：Carpentier’s techniques for degenerative posterior mitral leaflet （PML） prolapse have been established with excellent long-term results reported. However, residual mitral regurgitation（ MR） occasionally occurs even after a straightforward repair, though the involved mechanisms are not fully understood. We sought to identify specific preoperative echocardiographic findings associated with residual MR after a PML repair. Methods and Results：We retrospectively studied 117 consecutive patients who underwent a primary mitral valve repair for isolated PML prolapse including a preoperative three-dimensional ransesophageal echocardiography（ 3D-TEE） examination. Eleven had residual MR after the initial repair, of whom 7 required a corrective second pump run, 4 underwent conversion to mitral valve replacement, and 1 developed moderate MR within 1 month. Their preoperative parameters were compared with those of 105 patients who had an uneventful mitral valve repair. There were no hospital deaths. Multivariate analysis identified preoperative anterior mitral leaflet （AML） tethering angle as a significant predictor for residual MR ［odds ratio （OR） 6.82, 95％ confidence interval （CI） 1.8～33.8, p＝0.0049］. Receiver operator characteristics curve analysis revealed a cut-off value of 24.3°（ area under the curve 0.77）, indicating that AML angle predicts residual MR. In multivariate regression analysis, smaller anteroposterior mitral annular diameter（ p＜0.001） and lower left ventricular ejection fraction（ p＝0.002） were significantly associated with higher AML angle, while left ventricular and left atrial dimension had no significant correlation. Conclusions：AML tethering in cases of PML prolapse has an adverse impact on early results following mitral valve repair. The findings of preoperative 3D-TEE are important for consideration of a careful surgical strategy.

The natural prognosis of patients with aortic regurgitation （AR） has proved to be poorer than one might expect, thus surgical intervention should be recommended earlier than before. The most of patients with AR are relatively younger and therefore may benefit from aortic valvuloplasty （AVP） to eliminate prosthesis-related late adverse events. However, AVP does not seem popular enough because long-term durability after AVP is still unclear. For this purpose, long-term outcomes after AVP should be improved by standardizing the procedure, especially using aortic root remodeling procedure combined with external suture annuloplasty. The detail of the standardization of these procedures is outlined in this review briefly. We hope more and more aortic valves of the patients with not only aortic root dilatation but also isolated AR will be preserved based on this review in the near future.

According to the current guideline, early surgery is recommended in patients with infective endocarditis （IE）. On the other hand, mitral valve plasty （MVP） became the preferred surgical option in patients with IE, because of its benefits in the preservation of left ventricular function and prevention of recurrence of infection. Feasibility of MVP is an important issue in surgical strategy, however, it might be associated with the timing of the operation：feasibility of MVP might be higher in healed IE than active IE, although there had been no clear evidence in previous studies. In order to develop scoring system to predict feasibility of MVP in patients with active IE, we have introduced “severity score”．Severity score defined as the sum of valvular score which evaluates the extensiveness of the valvular destruction, and technical score which evaluates the complexity and durability of the repair. Probability of feasible MVP was high in severity score≦7 points and low in severity score≧9 points. MVP is basically selected in patients with severity score of 8 points, taking the benefit of patients and risks of longterm durability into consideration. We believe that severity score is valuable and reproducible scoring system in surgical decision making.

Long-term results of valve repair for aortic regurgitation is not still clear. We investigated retrospectively our results of aortic valve repair for 244 patients. There were 2 operative death and 7 late cardiac death. Ten-year late survival rate was 84％ and 10-year reoperation free rate was 74％．That of congenital group was 57％．However, 10-year reoperation rate was 87％ for Type 1 group and 79％ for Type 2 group. Recent technical evolution such as introduction of 4-dimensional computed tomography （CT） and intraoperative measurement of effective height may contribute improvement of repair technique. Further accumulation of evidence will promote earlier surgery for patients with aortic regurgitation.