Transcatheter Aortic Valve Replacement: Current and Emerging Approaches

Improved Delivery Systems

“As newer devices are developed and approved, the older ones may become obsolete,” commented Dr Dvir.

The PARTNER 2B trial compared two transcatheter valves: the Edwards SAPIEN and the SAPIEN XT, a second-generation SAPIEN device that has a lower profile delivery system. The SAPIEN XT showed significant reduction in major vascular complications (9.6% vs 15%, P=.04) without an increase in mortality or stroke rates.¹³

A study of 125 TAVR patients using the newest generation SAPIEN 3 found excellent procedure and short-term outcomes, with virtually no paravalvular regurgitation (PAR).¹² Data presented at the 2015 the American College of Cardiology meeting found that at 30 days, the SAPIEN 3 produced a 2.2% mortality rate and 1.5% stroke rate in high-risk patients (n=583). In the intermediate-risk patient group (n=1076), 30-day mortality rate was low (1.1%), and their total stroke rate was 3%, with a disabling stroke rate of 1%. In both groups, the risk of PAR was 3.7%.¹⁴

At the 2015 Transcatheter Cardiovascular Therapeutics meeting, the annual scientific symposium of the Cardiovascular Research Foundation, data were presented regarding 1-year results from the PARTNER II trial of high-risk patients who received the SAPIEN XT (n=197) valve-in-valve device. These patients had had a 13.4% all-cause mortality rate (the primary end point) and an 8.9% rate of cardiac mortality. The 1-year stroke rate was 3.7% and the rehospitalization rate was 11.8%.¹⁵ These promising findings led to the recent US Food and Drug Administration (FDA) approval of the SAPIEN XT for this indication.

The CoreValve system has also gone through an evolutionary process. Two-year data were presented from the CoreValve US Pivotal Trial High Risk Study, comparing CoreValve to SAVR in the treatment of symptomatic severe AS in high-risk and very high-risk subjects (n=747). The 1-year survival rate for TAVR vs SAVR was 4.8% and the 2-year survival rate was 6.4%. The researchers concluded that TAVR conferred superior survival at 2 years, as compared with SAVR.¹⁶ 

“Each delivery system has advantages and disadvantages, and each is appropriate for different populations,” Dr Dvir said.

Advantages and disadvantages of delivery systems can be found in Table 2. FDA approvals and indications can be found in Table 3.

Table 2: SAPIEN vs CoreValve: Advantages and Disadvantages

SAPIEN XT vs CoreValve
SAPIEN XT	CoreValve
Advantages Suitable for dilated ascending aorta Suitable for valve-in-valve (all 4 valves)	Advantages Reduced height for better fit, especially in angulated anatomies Preserves aortic annulus circularity Supra-annular design No need for rapid ventricular pacing Multiple entry points
Disadvantages Not repositionable Not retrievable Axial alignment depends on anatomy No anatomic implantation Risk of annular rupture Paravalvular leaks Single shot procedure	Disadvantages Not repositionable Not retrievable Axial alignment depends on anatomy High pacemaker rate Frame expands into ascending aorta, partially covering coronaries Final movement in moment of release Paravalvular leaks
SAPIEN 3 vs CoreValve Evolut R
SAPIEN 3	CoreValve Evolut R
Advantages Expandable, recollapsible sheath Can be used in degenerated aortic, mitral, tricuspid bioprostheses and mitral valve rings Lower incidence of conduction abnormalities/pacemaker implantation Less paravalvular regurgitation High flexibility Low-profile expandable e-Sheath	Advantages Smaller sheath size Smaller aortic annulus size Shorter valve Generally less paravalvular regurgitation Fewer vascular complications Recapturable Repositionable
Disadvantages Not re-sheathable or repositionable Oversizing increases risk of aortic annulus rupture Need rapid ventricular pacing Less appropriate for large annulus	Disadvantages Permanent pacemaker implantation In patients with greater annulus calcification, annulus eccentricity, and aortic ventricle outflow tract angle, more likely to have PAR

References

Stathogiannis K, Synetos A, Toutouzas K, et al. Medtronic CoreValve: achieving optimal outcomes. Hellenic J Cardiol. 2015;56 Suppl A:4-8.

Halapas A, Chrissoheris M, Bouboulis N, et al. The SAPIEN-XT and SAPIEN-3 valves: how to implant and obtain best outcomes. Hellenic J Cardiol. 2015;56 Suppl A:9-14.

Iqbal J, Serruys PW. Comparison of Medtronic CoreValve and Edwards SAPIEN XT for transcatheter aortic valve implantation: the need for an imaging-based personalized approach in device selection. JACC Cardiovasc Interv. 2014;7(3):293-295.

Table 3: United States Food and Drug Administration (FDA) Approvals of TAVR Devices

Device	Indication
Edwards SAPIEN XT and Medtronic CoreValve	Symptomatic severe native calcific aortic stenosis at high or greater risk for open surgical therapy Patients with failure (stenosis, regurgitation, or combined) of a surgical bioprosthetic aortic valve at high or greater risk for open surgical therapy
Edwards SAPIEN 3	Patients with aortic stenosis in patients with symptomatic heart disease due to severe native calcific aortic stenosis, at high or greater risk for open surgical therapy
Edwards SAPIEN XT and Medtronic CoreValve	Patients who need replacement of a failed tissue aortic valve but are at extreme or high risk of death or serious complications from traditional open-heart surgery
Medtronic CoreValve Evolut R	Patients with severe aortic stenosis who are at high or extreme risk for surgery

References

US Food and Drug Administration. Edwards SAPIEN XT transcatheter valve-P130009. Updated July 15, 2014. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm405068.htm. Accessed December 2, 2015.

US Food and Drug Administration. Medtronic CoreValve system-P130021. Updated April 1, 2014. http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm384592.htm. December 2, 2015.

FDA expands use of CoreValve for aortic “valve-in-valve” replacement [news release]. Silver Spring, MD: US Food and Drug Administration; March 30, 2015.http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm440535.htm. Accessed December 2, 2015

Edwards SAPIEN XT valve receives FDA approval for aortic valve-in-valve procedures [news release]. Irvine, CA: Edwards Lifesciences; October 15, 2015. http://www.edwards.com/eu/newsroom/Pages/ShowPR.aspx?PageGuid=%7B0042cad6-bfed-497a-862b-818a1bad8ab9%7D. Accessed December 2, 2015.

FDA approves SAPIEN 3 THV artificial heart valve [press release]. Silver Spring, MD: US Food and Drug Administration; June 17, 2015. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm451678.htm. December 2, 2015.

Medtronic announces FDA approval for new TAVR system, introduces first and only recapturable heart valve in US [press release]. Dublin, Ireland: Medtronic; June 23, 2015. http://newsroom.medtronic.com/phoenix.zhtml?c=251324&p=irol-newsArticle&ID=2061818. December 2, 2015.