Minimally invasive approach for redo mitral valve surgery

Abstract

Redo cardiac surgery represents a clinical challenge due to a higher rate of peri-operative morbidity and mortality. Mitral valve re-operations can be particularly demanding in patients with patent coronary artery bypass grafts, previous aortic valve replacement, calcified aorta or complications following a previous operation (abscesses, perivalvular leaks, or thrombosis). Risk of graft injuries, hemorrhage, the presence of dense adhesions and complex valve exposure can make redo valve operations challenging through a median sternotomy. In this review article we provide an overview of minimally invasive approaches for redo mitral valve surgery discussing indications, techniques, outcomes, concerns and controversies. Scientific literature about minimally invasive approach for redo mitral surgery was reviewed with a MEDLINE search strategy combining "mitral valve" with the following terms: 'minimally invasive', 'reoperation', and 'alternative approach'. The search was limited to the last ten years. A total of 168 papers were found using the reported search. From these, ten papers were identified to provide the best evidence on the subject. Mitral valve reoperations can be safely and effectively performed through a smaller right thoracotomy in the fourth intercostal space termed "mini" thoracotomy or "port access". The greatest potential benefit of a right mini-thoracotomy is the avoidance of sternal re-entry and limited dissection of adhesions, avoiding the risk of injury to cardiac structures or patent grafts. Good percentages of valve repair can be achieved. Mortality is low as well as major complications. Minimally invasive procedures with an unclamped aorta have the potential to combine the benefits of minimally invasive access and continuous myocardial perfusion. Less invasive trans-catheter techniques could be considered as the natural future evolution for management of structural heart disease and mitral reoperations. The safety and efficacy of these procedures has never been compared to open reoperations in a randomized trial, although published case series and comparisons to historical cohorts suggest that they are an effective and feasible alternative. Ongoing follow-up on current series will further define these procedures and provide valuable clinical outcome data.

Keywords: Mitral valve; minimally invasive approach; reoperation.

Figure 1

A right antero-lateral skin is performed under the nipple to obtain the access at the 4° intercostal space. Two ports are introduced to indroduce the optic, the CO₂ and the sucker.

Figure 2

Isolation of the femoral artery and vein for ExtraCorporeal Circulation; cannulation is usually performed with the Seldinger technique, without vessel clamping.

Figure 3

Video-assisted examination of a dehiscent mitral ring in a patient with severe mitral regurgitation and previous failed repair.

Figure 4

Video-assisted implantation of a bioprosthetic mitral valve after removal of the ring, in a patient with severe mitral regurgitation and previous failed repair.

Video 1

Dehiscence of an annuloplasty ring with residual mitral regurgitation. The operation was performed on the empty beating heart with a naso-pharyngeal temperature of 33 °C after a right antero-lateral mini-thoracotomy at the 4^th intercostal space, an aortic vent under continuous suction was previously placed in the ascending aorta to evacuate air. The left atrium was opened with a para-septal incision. The dehiscent ring (from A1 to P2) was exposed using an atrial retractor, paying attention to minimize aortic insufficiency. An additional left atrial pump sucker was used to maintain a clear operative field. The ring was completely removed with a sharp scalpel. Single pledgeted U stiches (pledget on the ventricular side) were positioned in the usual fashion. The mitral valve replacement was performed with a biological prosthesis. Knots were pulled down and sutures cut. Once mitral replacement was completed, we observed the absence of periprosthetic leaks thanks to the beating heart technique.