Mind the step!

Minimally invasive surgery, Re-operation, Mitral valve

In this issue of the European Journal of Cardiothoracic Surgery, a study reporting the results of a re-do port-access mitral valve surgery is presented [1]. The authors claim that the technique is safe, can be performed with a reasonable mortality and it offers a low rate of wound infections and a short intensive care unit (ICU) and hospital stay. They have consequently elected port-access technique as the treatment of choice for re-operative mitral valve surgery. These data are consistent with that in the literature. In their detailed review, Modi and colleagues stated that minimally invasive mitral valve surgery can be performed with equal mortality and neurological events, with less need for re-operation for bleeding, shorter hospital stay, less pain and faster return to usual occupations, despite longer cardiopulmonary bypass and cross-clamp times than conventional surgery. Data also showed that re-operative minimally invasive mitral valve surgery requires fewer transfusions and is associated with a faster recovery and greater patient satisfaction [2]. These findings have been recently confirmed in a meta-analysis focussed on re-operative minimally invasive mitral valve surgery alone [3].

Ricci and colleagues have accumulated, over a decade, an impressive experience in port-access surgery, and even if their report presents all the limitations of an observational study it is a unique opportunity for surgeons interested in including this technique in their armamentarium.

The hidden message of the study, revealed by the honest report of complications and by the lucid analysis of their causes, is that opening new roads may be hard and frustrating and that, behind the feasibility of a new approach, there is a lot of pain and fatigue.

At the present time, it is clear that a patient’s request for minimally invasive approaches will increase; it has also been established that the technique is feasible and reproducible. However, the open questions are, how surgeons performing extremely well with conventional techniques should approach minimally invasive surgery without accepting compromises? To what extent is it worth accepting a learning curve?

The report by Ricci and colleagues may answer some of these questions. It is evident that at least in the initial phase of their experience they had to face the unknown by accepting some sort of compromise. First, the rate of neurological events reported is excessively high. Independently from its cause, irrespective of it being the retrograde aortic perfusion or the inadequate de-airing, it is a problem intrinsic to the technique and only partially amenable by surgical skill or experience. Second, one of the main theoretical advantages of port-access surgery in patients undergoing re-operative mitral valve surgery is to avoid damaging or manipulating patent aorto-coronary grafts. The presence of patent grafts, however, can be a special challenge even with port-access technique because pedicled arterial grafts cannot be used to deliver cardioplegia. Moreover, depending on the position of their origin relative to the endoclamp, venous grafts can receive cardioplegia, if their origin is between the aortic valve and the endoclamp, or blood coming from the cardiopulmonary bypass return cannula if their origin is located downstream to the endoclamp or, in the worst scenario, they cannot receive blood if their origin is occluded by the endoclamp. To perfuse some myocardial segments with blood and others with cardioplegia or to use hypothermic myocardial perfusion can be the possible solutions, the fact that these kinds of myocardial protection are not routinely used in cardiac surgery is however here to testify that this is again a compromise, and not the optimal option for the patient. As a result, to avoid a ‘blind’ sternotomy and manipulation of grafts, a blind myocardial protection has to be accepted. The combined incidence of low cardiac output, death due to low cardiac output and need for extracorporeal membrane oxygenation (ECMO) reported in the study may in fact reflect a problem with myocardial protection. This problem once again is intrinsic to the technique adopted. Finally, the authors report a low rate of mitral valve repair and a risible rate of atrial fibrillation treatment occurrences, which might reflect the need to adapt the operative plan to the technique. By stating in the study that ‘AF treatment requires more extensive isolation of cardiac structures that may void the advantages provided by this minimally invasive approach,’ they give, as acquired, the notion that for a given patient it is better to have atrial fibrillation for the rest of his life than have some atrial dissection at the time of surgery. Probably not all of the readers will agree with this approach, which again sounds like a compromise.

Keeping in mind that the significance of complications and their relative weight is clearly amplified in experienced hands, the high incidence of major complications reported confirms the feeling that the price to pay to achieve good results in centres inexperienced in port-access surgery could be very high.

The advanced application of port-access technology proposed by Ricci and colleagues has probably been only the final point of a complex process starting with cautious application of the technique in an easier setting and in selected patients followed by progressive steps towards its extensive use. We must be careful however, because the final step can be very difficult to climb. The authors should be commended for their effort in driving the development of the technique. Nonetheless, re-operative mitral valve surgery can be done and is actually done by the vast majority of cardiothoracic surgeons without port access with excellent results. At the moment, surgeons must be cautious and well prepared to apply minimally invasive techniques in this field with a real satisfaction.