TAVI is on the move! How it compares with surgery and what complications we still have to consider

For the podcast associated with this article, please visit https://academic. oup.com/eurheartj/pages/Podcasts. Aortic stenosis is one of the most common valvular conditions in Western countries and is steadily increasing with the ageing population in this part of the world. In the 1950s surgical valve replacement became available, initially with mechanical and later biological valves. Due to the risk of surgery, particularly in the elderly and frail,1 as well as in multimorbid individuals, the condition was undertreated. This changed with the introduction of transcatheter aortic valve implantation (TAVI), a novel procedure that is increasingly used in both the USA2 and Europe.3 At first, only inoperable patients were considered for the new procedure,4 then high-risk, intermediate-risk,5 and now even low-risk patients6,7—and development is consistently moving forward: 8 It is conceivable that in the near future, the majority of such patients will undergo TAVI rather than surgery. However, TAVI has to pass the test. The current situation is described in the FAST TRACK manuscript entitled ‘Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of symptomatic severe aortic stenosis: an updated meta-analysis’ by Stephan Windecker and colleagues from the University Hospital Bern in Switzerland.9 They extracted seven randomized trials with 8020 patients, interventions, and outcomes following pre-defined criteria, with all-cause mortality up to 2 years as the primary outcome. The combined mean STS score in the TAVI arm was 9.4, 5.1, and 2.0% for high-, intermediate-, and low-surgical risk trials, respectively. TAVI was associated with a significant reduction of all-cause mortality compared with surgical aortic valve replacement, with a hazard ratio of 0.88, an effect that was consistent across the entire spectrum of surgical risk and irrespective of the type of the TAVI valve system (Figure 1). TAVI resulted in lower risk of strokes, with a hazard ratio of 0.81, while surgery was associated with a lower risk of major vascular complications and permanent pacemaker implantations, with a hazard ratio of 2.27. Thus, compared with surgery, TAVI is associated with reduction in all-cause mortality and stroke up to 2 years irrespective of baseline surgical risk and type of TAVI system. These impressive results are put into clinical context in an Editorial by John Webb from St. Paul’s Hospital in Vancouver, Canada.10 Meta-analysis for the primary outcome all-cause mortality comparing transcatheter aortic valve implantation vs. surgical aortic valve replacement up to 2-year follow-up stratified by baseline surgical risk at study level. For each trial, boxes and horizontal lines correspond to the respective point estimate and accompanying 95% confidence interval. A summary estimate is provided for each subgroup of trials according to surgical risk. The size of each box is proportional to the weight of the individual trial result. The vertical solid line on the forest plot represents the point estimate of hazard ratio = 1. The vertical dashed line on the plot represents the point estimate of overall hazard ratio derived from random-effect meta-analysis [hazard ratio 0.88 (95% confidence interval 0.78–0.99), P = 0.030]. The diamond represents the 95% confidence interval of the summary pooled estimate of the effect and is centred on pooled hazard ratios. Heterogeneity estimate of τ2 accompanies the summary estimate. The P-value for linear trend from random-effects meta-regression is P = 0.983 (from Siontis GCM, Overtchouk P, Cahill TJ, Modine T, Prendergast B, Praz F, Pilgrim T, Petrinic T, Nikolakopoulou A, Salanti G, Søndergaard L, Verma S, Jüni P, Windecker S. Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of symptomatic severe aortic stenosis: an updated meta-analysis. See pages 3143–3153). Like surgery, TAVI is also not without complications. Besides vascular complications, paravalvular leaks, and pacemaker requirement are still relatively common,11 while aortic rupture, ventricular perforation,12 and peri-procedural TAVI valve embolization and migration are rare, but potentially devastating when they take place. In their article ‘Incidence and outcome of peri-procedural transcatheter heart valve embolization and migration: the TRAVEL registry (TranscatheteR HeArt Valve EmboLization and Migration)’ Won-Keun Kim and colleagues from the Kerckhoff Heart Center in Bad Nauheim, Germany assessed the incidence, causes, and outcome of this complication in a large multicentre cohort.13 Peri-procedural TAVI valve embolization and migration occurred in 0.92% of 29 636 TAVI procedures, of which 217 were to the ascending aorta and 56 to the left ventricle (Figure 2). The use of self-expanding or first-generation prostheses, and presence of a bicuspid aortic valve were independent predictors of TAVI embolization and migration. Overview of the main causes, onset, bail-out strategies, and outcome of transcatheter valve embolization and migration stratified according to aortic and ventricular embolization. TVEM, transcatheter valve embolization and migration; VinV, valve-in-valve (from Kim W-K, Schäfer U, Tchetche D, Nef H, Arnold M, Avanzas P, Rudolph T, Scholtz S, Barbanti M, Kempfert J, Mangieri A, Lauten A, Frerker C, Yoon S-H, Holzamer A, Praz F, De Backer O, Toggweiler S, Blumenstein J, Purita P, Tarantini G, Thilo C, Wolf A, Husser O, Pellegrini C, Burgdorf C, Antolin RAH, Díaz VAJ, Liebetrau C, Schofer N, Möllmann H, Eggebrecht H, Sondergaard L, Walther T, Pilgrim T, Hilker M, Makkar R, Unbehaun A, Börgermann J, Moris C, Achenbach S, Dörr O, Brochado B, Conradi L, Hamm CW. Incidence and outcome of peri-procedural transcatheter heart valve embolization and migration: the TRAVEL registry (TranscatheteR HeArt Valve EmboLization and Migration). See pages 3156–3165). Bail-out measures included repositioning attempts using snares or miscellaneous tools in 41%, multiple valve implantations in 83%, and conversion to surgery in 19%. In a propensity-matched cohort, all-cause mortality was higher in TAVI embolization and migration patients than in those without it at 30 days (18.6% vs. 4.9%) and at 1 year (30.5% vs. 16.6%). Major stroke was four times as frequent in TAVI embolization and migration at 30 days, but not at 1 year. The need for emergent cardiopulmonary support, major stroke at 30 days, and acute kidney injury stages 2 and 3 increased the risk of 1-year mortality, whereas a better renal function at baseline was protective. Thus, TAVI embolization and migration occurs in ∼1% and is associated with increased morbidity and mortality, a finding that is further discussed in an Editorial by Ronald K. Binder from the University Teaching Hospital Klinikum Wels Grieskirchen in Wels, Austria.14 Another common and important complication of TAVI is acute kidney injury due to the use of contrast medium, among other factors.15 It is associated with increased risk for short- and long-term mortality. In patients undergoing percutaneous coronary intervention (PCI), forced diuresis with matched hydration reduces the incidence of acute kidney injury by ∼50%.16,17 However, not much is known about the usefulness of this intervention during TAVI. In their Fast Track ‘Forced diuresis with matched hydration during transcatheter aortic valve implantation for reducing acute kidney injury: a randomized, sham-controlled study (REDUCE-AKI)’ Yaron Arbel et al. from the Tel-Aviv Medical Center in Israel evaluated whether forced diuresis with matched intravenous hydration reduces acute kidney injury in patients undergoing TAVI. 18 Reduce-AKI was a single-centre, prospective, randomized, double-blind sham-controlled clinical trial, designed to examine the effect of an automated matched saline infusion with urine output for the prevention of acute kidney injury in 136 patients undergoing TAVI. The rate of acute kidney injury was not different between the groups. There was an increase in long-term mortality in the active group (27.9% vs. 13.2%). Therefore, the study was terminated prematurely. Unlike in PCI, forced diuresis with matched hydration does not prevent acute kidney injury in patients undergoing TAVI, and might be associated with increased long-term mortality. Future studies should focus on understanding the mechanisms behind these findings, as further explored in an insightful Editorial by George L. Bakris from the Rush-Presbyterian-St. Lukes Medical Center in Chicago, Illinois (USA).19 Another structural percutaneous cardiac procedure is device closure of a patent foramen ovale (PFO20). Catheter-based PFO closure has been shown to reduce the incidence of cryptogenic stroke21 and may even ameliorate migraine 22 In his issue, Christian Pristipino and colleagues from the Eapci Scientific Documents and Initiatives Committee provide the position statement ‘European position paper on the management of patients with patent foramen ovale. General approach and left circulation thromboembolism’.23 They note that the presence of a PFO is implicated in the pathogenesis of a number of medical conditions; however, in spite of convincing randomized trials, the subject remains controversial and no official statements have been published. This interdisciplinary paper, prepared with involvement of eight European scientific societies, reviews the available trial evidence in a balanced fashion and defines the principles guiding decision-making in patients with a PFO. Finally, this issue is complemented by various Discussion Forum contributions. In the first one entitled ‘Perspective on the treatment of functional mitral regurgitation using the Cardioband System’, David Messika-Zeitoun from the University of Ottawa Heart Institute in Ontario, Canada and colleagues comment on an Editorial about one of their papers by Yaron Shapira from the Rabin Medical Center, Beilinson Hospital in Petah-Tiqva, Israel.24,25 In a second Discussion Forum contribution ‘Differential effects of training on telomerase activity and telomere length: the role of microRNAs regulation’, Salvatore Patanè from the Cardiologia Ospedale San Vincenzo-Taormina (Me) Azienda Sanitaria Provinciale di Messina in Italy comment on the recently published article ‘Differential effects of endurance, interval, and resistance training on telomerase activity and telomere length in a randomized, controlled study’ by Christian Werner and colleagues from the Universitätsklinikum des Saarlandes in Homburg, Germany.26,27 Dr David Jiménez-Pavón and colleagues from the Universidad de Cádiz in Puerto Real, Andalucía in Spain also discuss the article by Werner et al. in their contribution ‘Are changes in telomerase activity and telomere length due to different exercise modalities, intensity, or methods: intermittency?’,28 Werner et al. respond to the contributions by Patanè and Jiménez-Pavón in one response.29 In a further Discussion Forum ‘Air pollution vs. tobacco smoking’ Philippe Girard and colleagues from the Institut Mutualiste Montsouris in Paris, France comment on the recently published article ‘Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions’ by Thomas Münzel and colleagues from the Johannes Gutenberg Universität in Mainz, Germany.30,31 Münzel et al. respond in a separate comment.32 In another contribution ‘Can results of meta-analysis with high heterogeneity provide any predictive values?’, Yi Feng and colleagues from the Peking University People’s Hospital in Beijing, China comment on a recently published contribution entitled ‘A systematic review and meta-analysis of the prevalence of left ventricular non-compaction in adults’ by Chris Semsarian and colleagues from Royal Prince Alfred Hospital in Camperdown, Australia.33,34 Chris Semsarian et al. respond to the contribution in a separate contribution.35 Finally, in a Discussion Forum entitled ‘The role of sleep disorders breathing treatment as a modifiable condition for cardiovascular risk associated hypertension’ Olga Mediano and colleagues from the Hospital Universitario de Guadalajara in Spain comment on a recent contribution entitled ‘Asleep blood pressure: significant prognostic marker of vascular risk and therapeutic target for prevention’ by Ramon C. Hermida and the Hygia Project Investigators.36,37 Hermida and colleagues respond to Mediano in a separate contribution.38 The editors hope that readers of this issue of the European Heart Journal will find it of interest. With thanks to Amelia Meier-Batschelet for help with compilation of this article.