Favourable outcomes after high-risk conventional aortic valve replacement: can we do even better?

We read with great interest the article by Dimarakis et al. [1] and congratulate the authors for the excellent results they obtained in terms of both preoperative management, involving a multidisciplinary team to discuss treatment strategy, and postoperative outcome. The development of novel therapeutic options, such as transcatheter aortic valve implantation (TAVI), has provided renewed hope for patients whose conditions in the past would have been considered inoperable or high risk. However, in daily clinical practice, physicians frequently face patients who, despite being at high risk, have indication for conventional open surgery due to multiple comorbidities, or require concomitant coronary artery bypass grafting. Efforts should therefore be oriented to improve the outcome of high-risk patients undergoing conventional surgery with cardiopulmonary bypass (CPB), regardless of whether the ongoing PARTNER trial will prove the superiority of TAVI over surgery. We agree with Dimarakis et al. that treatment strategies should be tailored to the individual patient, e.g. the choice of the artery to be cannulated. Contact of the blood with foreign surfaces during CPB is still a challenging problem, and the possibility of modifying the CPB circuit to reduce the systemic inflammatory response is currently under investigation [2–4]. Despite the extensive literature available on this topic (1319 items on PubMed search for ‘cardiopulmonary bypass’ and ‘inflammation’), including review articles [3], several issues remain to be clarified. Goudeau et al. [5] evaluated the benefits of a therapeutic optimization of CPB through the combination of different procedures that reduce inflammatory response and oxidative stress. This approach proved effective in improving the clinical outcome. It is also well recognized that aortic cross-clamp time plays a relevant role. In their preliminary study with a sutureless implantable aortic bioprosthesis (Perceval S valve, Sorin, Saluggia, Italy), Flameng et al. [6] have recently obtained a very short aortic cross-clamp time (18 ± 6 min). In the experience at our centre with the Perceval bioprosthesis (67 valve implantations), we had an aortic cross-clamp time of 37.2 ± 12.7 min in 43 high-risk patients, a much shorter cross-clamp time than that reported by Dimarakis et al. (median 84 min, range 68–143 min), despite similar EuroSCORE values (logistic EuroSCORE 20 ± 11.2). Notably, 10 out of the 43 patients required combined surgery (5 coronary artery bypass grafting, 1 ventricular septal defect closure, 2 catheter ablation of atrial fibrillation, 1 ascending aorta replacement and 1 tricuspid valvuloplasty). Whether the reduction in implantation time will also result in improved outcome remains to be defined. In our opinion, however, such a remarkable reduction in blood contact time during CPB should be considered within the multidisciplinary and open debate about protection strategies in high-risk patients undergoing aortic surgery.