New challenges in the era of low-intermediate risk transcatheter aortic valve replacement: surgery for infective endocarditis

Nowadays, thanks to the results of trials [1, 2] demonstrating the non-inferiority of transcatheter aortic valve replacement (TAVR) to surgery in low-intermediate-risk patients, a significant rise in TAVR procedures has been recorded around the world. Consistently, more and more patients are experiencing endocarditis on transcatheter-implanted prosthesis. This new entity represents a very challenging condition, both from a diagnostic and a therapeutical point of view. In fact, while modified Duke criteria show a low sensitivity in this context and a multimodality imaging approach is often required to get to a final diagnosis [3], surgical management has been historically widely avoided, both for advanced age and elevated surgical risk of the first TAVR patients [4]. Furthermore, surgical explant has been described as technically challenging, due to stent endothelialization and penetration in the aortic wall or aortomitral continuity, sometimes requiring unplanned aortic root or bivalvular procedures [5, 6]. However, conservatively managed TAVR endocarditis has shown poor clinical outcomes [7]. In this issue of the Journal, Saha et al. [8] describe a multicentre experience on 69 patients who underwent cardiac surgery in the context of endocarditis on a transcatheter-implanted prosthesis. Their retrospective cohort is mainly constituted, at the time of TAVR, of low-intermediate surgical risk patients (median EuroSCORE II and STS PROM 5.3% and 1.8%, respectively). However, at cardiac reoperation, surgical risk appears significantly increased (median EuroSCORE II 17%, median STS PROM 3.1%), as confirmed by the rate of urgent, emergent or salvage surgery (81.1%), depressed left ventricular ejection fraction (46.4%) and chronic kidney disease (62.3%). Interestingly, the authors describe a quite uneventful surgical TAVR explant. The median cardiopulmonary bypass time was 108 min, the median cross-clamp time was 77 min and only 11.5% of patients required aortic root or supracoronary ascending aortic replacement. The complexity of such a population, however, is demonstrated by a more complicated postoperative course. In fact, almost 20% of the patients experienced an adverse cerebrovascular event, 16% of patients required tracheostomy, and nearly half of the population needed renal replacement therapy, with survival to discharge rate of 88.4% and a median length of hospital stay of 19 days. What is thus the best approach in this context? Current guidelines recommend early radical surgery in patients with prosthetic valve endocarditis and severe valve disfunction, heart failure or local uncontrolled infection [9]. On the other hand, the complexity of this population warrants a patient-centred and multidisciplinary approach, to be discussed in the ‘endocarditis team’. This interesting report suggests a more aggressive attitude in TAVR endocarditis, namely with early surgery whenever indicated. In fact, in patients with low-intermediate surgical risk, the main challenge remains surgical explant that, according to the authors, was technically easy in almost all the patients, as already reported elsewhere [10]. Unfortunately, no comparison of intraoperative and postoperative outcomes between early and late endocarditis is available, being older than 1-year TAVR implant linked with a more complex removal and an increased rate of unplanned aortic surgery [5]. In conclusion, TAVR endocarditis is a challenging and increasingly common scenario, without consensus on management. Attention should be focused on prevention and prompt diagnosis. Surgery may be considered an acceptable option, linked with an apparently low surgical complexity but often with a long postoperative course.