On-pump or off-pump transapical aortic valve implantation provides better clinical outcomes?

According to the study [1], transapical implantation of the aortic valve (TAP-AVI) seems to provide better early clinical outcomes compared to transfemoral [2] or conventional aortic valve replacement [3]. Even though, it appears to have a similar 30-day mortality rate (8%), it lacks the commonly observed neurological damage of the latter methods (10% and 3.7%, respectively) [2,3]. However, in our opinion there still remain open questions as to the methodology followed that will still take time to be answered before TAP-AVI becomes the golden scale in aortic valve stenosis therapy. In your material cardiopulmonary bypass (CPB) was required in a total of 32% of cases, in 10% of which it was acutely applied in order to avoid dramatic complications. Even if we do not ignore the learning curve, since many of the above cases were intentionally challenged, still, the percentage of inversion to CPB remains extremely high (above 10–15%). Especially, in the cases of inversion to sternotomy, awareness and readiness is of critical importance. Postoperative haemodynamic status of the patients included in this study has not been recorded. Was there continuous monitoring of cardiac output during the first 24 h? Judging from the fast track extubation one can conclude that in 42% of cases cardiac output was sufficient. What about the rest of the patients? Temporary occlusion of left ventricle outflow tract, even during the brief dilation and implantation time, combined coronary occlusion as well as rapid pacing of a severely hypertrophic myocardium, in our opinion will result in severe ischaemia. Beyond doubt, the latter will cause various degrees of postoperative dysfunction of the left ventricle, which will eventually constitute a negative factor for both early and late outcome. Poor 12-month survival demonstrated in this study (71%) compared to that of the conventional aortic valve replacement (72.4% [3], 56% [4]) is probably specifically related to this ‘intra-operative myocardial injury’ apart from all other comorbidity factors. Even though the degree of postoperational paravalvular leaks is described as low, in fact it is extremely high: 23/50 (46%) [1]. One can wonder whether this also contributes to poor late survival rate. Despite the fact that, as mentioned, these leaks are not the cause of severe haemolysis, they still remain a risk factor of late complications (i.e. endocarditis). The term ‘hybrid’, under which the technique is described, refers to percutaneous (or transfemoral) methodology performed by a cardiologist. In our opinion, TAP-AVI after median sternotomy combined with timely short CPB would be a true example of hybrid technique. Such a method would include all the advantages of an open operation as well as avoiding all the disadvantages of a percutaneous method: (a) no ischaemia or myocardial strain (b) absence of hypothermic state of cardioplegic arrest (c) CPB time will not exceed 25–30 min, thus minimal undesirable effects (d) sufficient perfusion of other vital organs (i.e. brain, kidneys) (e) potential application to any patient regardless of his haemodynamic status (f) thoracotomy substituted by the median sternotomy, which is safer g) offers the possibility of retrograde implantation through the ascending aorta if quality of the ascending aorta wall allows, and last (h) combined coronary artery by pass grafting (CABG) could be feasible since it is already required in up to 49% [5] of those patients.