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Editorial

Transcatheter aortic valve implantation

Alec Vahanian

Revista Argentina de Cardioangiología 2016;(4):0190-0193 


Este artículo no contiene resumen

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Los autores declaran no poseer conflictos de intereses.

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Recibido 2016-09-15 | Aceptado 2016-10-05 | Publicado 2016-12-30

 

1. What is the current evidence for TAVI?

 

We now have a large amount of evidence available from registries and also randomized clinical trials (RCT) comparing TAVI and surgical aortic valve replacement SAVR1-8.

The hemodynamic performance of the TAVI prostheses is at least as good, or even superior, to that of surgical prostheses, especially in patients with small aortic annulus where the incidence of mismatch is lower with TAVI.

A recent meta-analysis of all available randomized trials compared safety and efficacy of TAVI vs SAVR across the spectrum of risk ranging from inoperable patients toward high risk, intermediate risk and even all-comers. It should be noted that the prostheses used for TAVI were not the newest generation. It showed that TAVI was associated with a significant survival benefit throughout 2 years of follow-up9. The superiority of TAVI was observed, irrespective of the TAVI device, across the spectrum of intermediate, high-risk, or inoperable patients, and was particularly pronounced among patients undergoing transfemoral TAVI and in females. The risk of stroke, and that of myocardial infarction were the same for the two techniques. TAVI carried a lower risk of kidney injury, major hemorrhage, and new onset atrial fibrillation, SAVR performed better as regards the rate of vascular complications, paravalvular leakage as well as need for pacemaker implantation. Besides the randomized trials, the very large experience from registries in Europe and the US shows a dramatic reduction in technical complications of TAVI such as annular rupture, valve dislodgment or tamponade10 over time.The transfemoral approach has consistently shown a reduction in risk in comparison with other approaches.

The comparative results between TAVI and SAVR, available up to 5 years in inoperable and high risk patients, confirm the superiority of TAVI as regards survival and strokes, finding in addition an earlier functional recovery for TAVI4,5. However it should be stressed that long-term mortality remains high in this group of patients mostly due to extra-cardiac causes.

 

2. What do the guidelines say?

 

Both the ESC/EACTS (2012) and ACC/AHA guidelines concur that TAVI is indicated in patients who are inoperable, but have a sufficient life expectancy, and should be considered in high-risk patients11,12. They also consistently state that TAVI is not recommended in lower risk patients in whom surgery remains the preferred approach.

 

3. What happens in practice?

 

In Germany there are already more TAVI than SAVR performed. There is a current shift toward using TAVI in patients at lower estimated surgical risk. As an illustration the average STS risk score which was around 11% in the early US trial is now 5-7% in the most recent registries. The same trend holds to be true in Europe since in Germany 27% of patients undergoing TAVI in 2014 had Logistic EuroSCORE <10% (Frecker oral communication at annual ESC Congress 2016) and in the EAPCI survey (301 TAVI centres in 2015) 45% of centres claim that they perform TAVI in intermediate risk patients13.

 

4. How can we move forward?

 

This can be done as follows:

A. Improvement in the technique

Over 15 new devices are now commercially available with important new features. Some are iterations of the first generation while others represent new concepts such as reposition ability or retrievability. The extensive diversity of characteristics of the devices available will likely allow for a more individualised use of specific devices.

The new devices are easier to use, more predictable and offer better safety than the first generation14.

The results available with the newer devices clearly show that the incidence of paravalvular leaks is dramatically reduced, the incidence of moderate to severe AR being <5%. This is due to the availability of more sizes, improved positioning due to the possibility to reposition and retrieve certain devices, and better conformability.These improvements are in addition to the increased use of 3D imaging before the procedure, mostly using CT, which allows a more accurate sizing of the aortic annulus and therefore choice of the prosthesis.

The risk of stroke is also decreased due to better maneuver ability of delivery catheters, easier crossing of the valve, and more stable positioning of the prostheses across the valve. As a consequence balloon predilatation is less often needed. Certain prostheses also do not necessitate rapid pacing during deployment.

Vascular complications and severe bleeding are less frequent due to the decrease in sheath sizes and better delivery systems. This allows for an increasing use of the transfemoral approach which is now over 90%.

The downside of many of the new prostheses is an increase in the need for pacemaker, there is however an important heterogeneity across devices. This may be a concern in patients with low left ventricular ejection fraction and also when considering the extension of indications toward younger patients15.

Overall due to procedural and technological progress mortality during the procedure has dramatically decreased.

A matched comparison between the latest generation SAPIEN 3 device (Edwards Lifesciences) (registry) and SAVR (part of PARTNER 2 trial) was performed using a propensity score analysis, in 1,077 intermediate-risk patients16. At 1-year follow-up, in patients treated with the SAPIEN 3 the all-cause mortality was 7.4%, the occurrence of disabling stroke 2%, aortic valve re-intervention 1%, and moderate or severe paravalvular regurgitation 2%. Comparison with the surgical group revealed that, TAVI with SAPIEN 3 was superior to surgical AVR for the composite endpoint of mortality, stroke, re-intervention and moderate or severe aortic regurgitation at 1 year. However the rate of paravalvular leaks and need for pacemaker was higher in TAVI than in SAVR.

Experience and the use of the new devices led to simplify the overall performance of TAVI. Due to these factors and the use of the transfemoral approach in >90% of cases, less frequent use of transesophageal echocardiographic guidance and better safety, most procedures are now performed percutaneously and without general anesthesia. The duration of hospital stay has also dramatically reduced, down to a few days in the majority of patients. However, simplifying the procedure does not mean making it simplistic17.

Today it is still strongly recommended that TAVI is only performed in centres with cardiac surgery on site where a functioning heart team is available.The core of the heart team is composed of cardiologists (clinicians,interventionists,imaging specialists) and surgeons with knowledge in valvular heart disease actively collaborating for patient selection, procedural performance and post-interventional care11,12.

 

B. Definition of the indications for intervention

As of now the most important part of the decision making process is based on the assessment of surgical risk. This process however has serious limitations. It is difficult to estimate the risk of surgery using the traditional surgical risk scores such as EuroSCORE or STS, which were derived from lower risk populations and do not take into account several variables such as frailty or anatomical factors such as calcification of the ascending aorta or presence of patent aorto coronary grafts which are frequently seen in TAVI candidates. Thus, as stated in the ESC/EACTS guidelines, the risk assessment should mostly rely on the judgement of the heart team taking into account all the patients characteristics. The ACC/AHA guidelines correctly specified that the risk assessment should include both the surgical risk scores and variables evaluating frailty, major organ compromise and also technical aspects.

It is expected that the indications for TAVI will be taken cautiously in inoperable patients, carefully avoiding the procedure in patients where any intervention is “more futile than utile”. This requires a comprehensive evaluation by the heart team extended as necessary to other specialists, first of all geriatricians18.

The indications of TAVI will most likely be expanded to elderly patients at lower risk. The existing evidence supports the use of TAVI in “intermediate risk patients”. The PARTNER 2 trial showed that after 2 years there was no significant difference for mortality and stroke between TAVI and SAVR while TAVI is superior to surgery if performed via a transfemoral approach. The ongoing SURTAVI and UK trials will further address this question. Furthermore, the use of TAVI in low risk patients will be studied in specific randomised controlled trials.

In the future, it is likely that the indications for TAVI will rely more on specific anatomic and clinical factors than on scores19.

Further extension of the use of TAVI to low risk patients will require several other issues to be addressed:

More data on long-term follow-up are needed. As previously shown, there is no alarming information as regards the durability of TAVI prostheses in the carefully conducted RCT comparing the technique with surgery up to 5 years4,5. The same findings are made in registries up to 7 years20. Preliminary studies focusing on valve deterioration are ongoing and suggest that there is a small but present incidence of hemodynamic deterioration during follow-up. Prosthesis degenerationis more frequent in patients with risk factors for deterioration of any bioprosthesis:renal insufficiency, prosthetic mismatch, or absence of anticoagulation21. Longitudinal studies with longer follow-up, comprising comprehensive clinical and echocardiographic follow-up with a precise and clinically meaningful definition of valve deterioration are needed before any conclusion can be drawn.In case of failure “TAVI in TAVI” seems a promising approach but the results of this approach need to be evaluated. The question of durability should be unequivocally answered before considering the extension of TAVI toward younger patients.

The TAVI population is also at high risk for embolism and bleeding and antithrombotic regimens after TAVR are expert consensus-based and influenced by patient comorbidities. This calls for the evaluation of:

New anticoagulation regimens: several randomized trials are ongoing evaluating the need for combined antiplatelet agents or the usefulness of new antithrombotic agents22.

Cerebral protection devices: preliminary randomized studies suggest a decrease in MRI signals but failed to show a reduction in clinical events.These devices may be useful in selected high-risk patients (23).

Better detection and treatment of new onset atrial fibrillation both before and after TAVI.

Further evaluation of subclinical non-obstructive valve thrombosis with early leaflet thickening and reduced motion which has recently been documented when using high resolution CT imaging after TAVI. These changes were not associated with clinical symptoms, although an increase in transvalvular pressure gradients was occasionally detected. Full anticoagulation led to almost complete resolution of the problem24. The incidence and consequences of subclinical thrombosis remain to be established.

Management of associated coronary artery disease.The data on this topic are still limited to heterogeneous series with somewhat discordant results. The ongoing RCT “ACTIVATION trial” will help to define the best strategy. The indication for revascularisation depends on the clinical presentation,the extent of myocardium at risk and the feasibility of percutaneous intervention. In practice today TAVI is performed in isolation, revascularisation when needed is performed before TAVI. Finally data on the feasibility and results of revascularisation after TAVI are needed, especially when considering the extension of TAVI toward younger patients in the future.

Use of TAVI in patients with bicuspid valves. The incidence of bicuspid valve is rather low in the current TAVI population but will be much higher if younger patients are being treated. Patients with bicuspid valves were excluded from the RCT and current experience is limited to observational registries including a total of a few hundred patients.These initial results suggest the need for a comprehensive characterization of the anatomy of the valve and the ascending aorta by CT before the procedure.The incidence of paravalvular regurgitation decreases when using the new devices25. Long-term results need to be assessed.

The logistics must be solved! It has been shown that TAVI use varies greatly from one country to another and is influenced by specific health economics issues (GDP, source of funding, reimbursement etc.)26.

The costs of TAVI remain too high mostly due to the high cost of the devices.This will hopefully decrease with increased competition between devices. The costs of the hospital stays have already decreased due to the simplification of the procedure, the lower complication rate and shorter stay. Cost efficiency analyses are needed to convince the payers and regulators.

Finally the increasing number of TAVI procedures in a given institution creates several challenges as regards increased availability of trained interventionists, anesthesiologists, catheterization laboratories and hybrid rooms, intermediate care beds etc.

 

Conclusion

 

The development of TAVI is a success story. The technical progress will contribute, along with better patient selection, improved procedural performance, better adjunctive medical treatment /accessory devices and accumulation of evidence, to expanding the indications of TAVI toward lower risk patients.

  1. Gilard M, Eltchaninoff H, Iung B, Donzeau-Gouge P, Chevreul K, Fajadet J, et al.; FRANCE 2 Investigators. Registry of transcatheter aortic-valve implantation in high-risk patients. N Engl J Med 2012;366:1705-15.

  2. Eggebrecht H, Bestehorn M, Haude M, Schmermund A, Bestehorn K, Voigtländer T, et al. Outcomes of transfemoral transcatheter aortic valve implantation at hospitals with and without on-site cardiac surgery department: insights from the prospective German aortic valve replacement quality assurance registry (AQUA) in 17,919 patients. Eur Heart J. 2016;37:2240-8.

  3. Mack MJ, Brennan JM, Brindis R, Carroll J, Edwards F, Grover F, et al.; STS/ACC TVT Registry. Outcomes following transcatheter aortic valve replacement in the United States. JAMA 2013;310:2069-77.

  4. Kapadia SR, Leon MB, Makkar RR, Tuzcu EM, Svensson LG, Kodali S, et al.; PARTNER trial investigators. 5-year outcomes of transcatheter aortic valve replacement compared with standard treatment for patients with inoperable aortic stenosis (PARTNER 1): a randomised controlled trial. Lancet 2015;385:2485-91.

  5. Mack MJ, Leon MB, Smith CR, Miller DC, Moses JW, Tuzcu EM, et al.; PARTNER 1 trial investigators. 5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial. Lancet 2015;385:2477-84.

  6. Reardon MJ, Adams DH, Kleiman NS, Yakubov SJ, Coselli JS, Deeb GM, et al. 2-year outcomes in patients undergoing surgical or self-expanding transcatheter aortic valve replacement. J Am Coll Cardiol 2015;66:113-21.

  7. Leon MB, Smith CR, Mack MJ, Makkar RR, Svensson LG, Kodali SK, et al.; PARTNER 2 Investigators.Transcatheter or surgical aortic-valve replacement in intermediate-risk patients. N Engl J Med 2016;374:1609-20.

  8. Thyregod HG, Steinbrüchel DA, Ihlemann N, Nissen H, Kjeldsen BJ, Petursson P, et al. Transcatheter versus surgical aortic valve replacement in patients with severe aortic valve stenosis: 1-year results from the all-comers NOTION randomized clinical trial. J Am Coll Cardiol 2015;65:2184-94.

  9. Siontis GC, Praz F, Pilgrim T, Mavridis D, Verma S, Salanti G, et al. Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis: a meta-analysis of randomized trials. Eur Heart J 2016 Jul 7. pii: ehw225 [Epub ahead of print].

  10. Walther T, Hamm CW, Schuler G, Berkowitsch A, Kötting J, Mangner N, et al.; GARY Executive Board. Perioperative results and complications in 15,964 transcatheter aortic valve replacements: prospective data from the GARY registry. J Am Coll Cardiol 2015;65:2173-80.

  11. Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC); European Association for Cardio-Thoracic Surgery (EACTS), Vahanian A, Alfieri O, Andreotti F, Antunes MJ, Barón-Esquivias G, Baumgartner H, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J 2012;33:2451-96.

  12. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Guyton RA, et al.; American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;63:e57-185. Erratum in: J Am Coll Cardiol 2014;63:2489.

  13. Petronio AS, Capranzano P, Barbato E, Piazza N, Baumbach A, Haude M, Windecker S. Current status of transcatheter valve therapy in Europe: results from an EAPCI survey. EuroIntervention 2016;12:890-5.

  14. Athappan G, Gajulapalli RD, Tuzcu ME, Svensson LG, Kapadia SR. A systematic review on the safety of second-generation transcatheter aortic valves. EuroIntervention 2016;11:1034-43.

  15. Dizon JM, Nazif TM, Hess PL, Biviano A, Garan H, Douglas PS, et al.; PARTNER Publications Office. Chronic pacing and adverse outcomes after transcatheter aortic valve implantation. Heart 2015;101:1665-71.

  16. Thourani VH, Kodali S, Makkar RR, Herrmann HC, Williams M, Babaliaros V, et al. Transcatheter aortic valve replacement versus surgical valve replacement in intermediate-risk patients: a propensity score analysis. Lancet 2016;387:2218-25.

  17. Barbanti M, Capranzano P, Ohno Y, Attizzani GF, Gulino S, Immè S, et al. Early discharge after transfemoral transcatheter aortic valve implantation. Heart 2015;101:1485-90.

  18. Puri R, Iung B, Cohen DJ, Rodés-Cabau J. TAVI or no TAVI: identifying patients unlikely to benefit from transcatheter aortic valve implantation. Eur Heart J 2016;37:2217-25.

  19. Vahl TP, Kodali SK, Leon MB. Transcatheter aortic valve replacement 2016: A modern-day “Through the Looking-Glass” adventure. J Am Coll Cardiol 2016;67:1472-87.

  20. Mylotte D, Andalib A, Thériault-Lauzier P, Dorfmeister M, Girgis M, Alharbi W, et al. Transcatheter heart valve failure: a systematic review. Eur Heart J 2015;36:1306-27.

  21. Del Trigo M, Muñoz-Garcia AJ, Wijeysundera HC, Nombela-Franco L, Cheema AN, Gutierrez E, et al. Incidence, timing, and predictors of valve hemodynamic deterioration after transcatheter aortic valve replacement: multicenter registry. J Am Coll Cardiol 2016;67:644-55.

  22. Iung B, Rodés-Cabau J The optimal management of anti-thrombotic therapy after valve replacement: certainties and uncertainties. Eur Heart J 2014;35:2942-9.

  23. Haussig S, Mangner N, Dwyer MG, Lehmkuhl L, Lücke C, Woitek F, et al. Effect of a Cerebral Protection Device on Brain Lesions Following Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis: The CLEAN-TAVI Randomized Clinical Trial. JAMA 2016;316:592-601.

  24. Pache G, Schoechlin S, Blanke P, Dorfs S, Jander N, Arepalli CD, et al. Early hypo-attenuated leaflet thickening in balloon-expandable transcatheter aortic heart valves. Eur Heart J 2016;37:2263-71.

  25. Yoon SH, Lefèvre T, Ahn JM, Perlman GY, Dvir D, Latib A, et al. Transcatheter Aortic Valve Replacement With Early- and New-Generation Devices in Bicuspid Aortic Valve Stenosis. J Am Coll Cardiol 2016;68:1195-205.

  26. Osnabrugge RL, Head SJ, Genders TS, Van Mieghem NM, De Jaegere PP, van der Boon RM, et al. Costs of transcatheter versus surgical aortic valve replacement in intermediate-risk patients. Ann Thorac Surg 2012;94:1954-60.

Autores

Alec Vahanian
Bichat Hospital, University Paris VII, Paris, France.

Autor correspondencia

Alec Vahanian
Bichat Hospital, University Paris VII, Paris, France.

Correo electrónico: revista@caci.org.ar

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Revista Argentina de Cardioangiología intervencionista
Número 4 | Volumen 6 | Año 2016

Titulo
Transcatheter aortic valve implantation

Autores
Alec Vahanian

Publicación
Revista Argentina de Cardioangiología intervencionista

Editor
Colegio Argentino de Cardioangiólogos Intervencionistas

Fecha de publicación
2016-12-30

Registro de propiedad intelectual
© Colegio Argentino de Cardioangiólogos Intervencionistas

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