Minimally Invasive Surgery
Surgical mitral valve repair is the gold standard for treating primary MR and around 95% of patients being treated in designated centres while the remaining 5% who are not suited for surgery, will be considered for one of the aforementioned transcatheter interventions. Its effectiveness on secondary MR is still disputed and current European guidelines encourage pharmacological management.56
Traditionally, surgical repair/replacement of the mitral valve was done via median sternotomy. In order to minimise mortality and morbidity, various minimally invasive approaches have been developed, but undoubtedly the most common approach is right minithoracotomy.56-58 A small incision is made in the 4th intercostal space, providing access to the heart. The intervention requires access to femoral vessels for peripheral cannulation and connection to a cardiopulmonary bypass machine (CPB). TEE is used for guidance. Wolfe et al present in great detail the surgical technique and the four pillars of a successful minimally invasive mitral valve surgery (MIMVS): adequate cannulation and perfusion, good view of the mitral valve, thorough cardiac protection and procedure match to specific pathology and aetiology of MV defect.58
For correction of degenerative MR, one of the most prevalent MV pathologies, great results have been recorded using a non-resectional repair technique and implantation of new chordae using the loop technique, accompanied by ring annuloplasty for better resilience in the long-term. MV repair in the case of endocarditis is based on the removal of infected tissue and the use of a pericardial patch or repair using primary suturing, along with artificial chordae implant and ring annuloplasty. Annuloplasty with a closed, undersized ring is also used in the operation for ischemic MR.57, 59,60
Less perioperative complications (especially blood loss), decreased chances of surgical wound infection, as well as a shorter recovery period, have been the main advantages of MIMVS.57,61,62 Operative survival rate in multiple retrospective studies has been 100% and mortality rate at 30-day follow up is between 0.2 to 4.8%, depending on patient profile, higher mortality being recorded for patients undergoing MIMVS with concomitant tricuspid valve repair or coronary artery bypass grafting.60,63,64 Disadvantages of MIMVS, compared to standard sternotomy, include longer CPB time and increased risk of stroke during or immediately after intervention (almost 2.6% of patients have reported ischemic strokes).59