Author + information
- Kreton Mavromatis, MD∗ ()
- ↵∗Address for correspondence:
Dr. Kreton Mavromatis, Emory University/Atlanta VA Medical Center, 1670 Clairmont Road, 111B, Decatur, Georgia 30033.
Transcatheter heart valve (THV) technology has revolutionized aortic valve stenosis treatment. Currently, 2 THVs dominate the market worldwide, the balloon-expandable Sapien 3 (Edwards Lifesciences, Irvine, California) and the self-expanding Evolut (Medtronic, Dublin, Ireland) valves. However, 2 additional THVs have a small, but growing, presence in the “outside U.S.” market, and are in a race to be the third and fourth THVs to the U.S. market: the mechanically expandable Lotus (Boston Scientific, Natick, Massachusetts) and the self-expanding Portico (St. Jude Medical, Saint Paul, Minnesota). (A fifth valve, the Direct Flow, left the market after the relatively small company making it closed.)
The Portico THV—first approved for commercial use in Europe in November 2012—is a self-expanding nitinol valve with relatively large cells, bovine pericardial leaflets designed to be located at the level of the annulus, and a porcine inner cuff for annular sealing. The Portico delivery system consists of an 18- or 19-F capsule containing the valve on a 12-F shaft, which can be delivered through an 18- or 19-F sheath or through the expandable Solopath sheath (Terumo, Tokyo, Japan) with a 13.5- or 15-F insertion diameter. Available valve sizes (23 mm, 25 mm, 27 mm, and 29 mm) are suitable for 19- to 27-mm diameter annuli. The valve is considered fully retrievable before 80% deployment.
Potential advantages of the Portico over the self-expanding Evolut valve may be simpler, faster valve loading (no need for cold saline); more flexible delivery system for better tracking through tortuosity; intra-annular valve position resulting in more hemodynamic stability during deployment; larger stent cells resulting in more cuff–annulus interaction, reducing paravalvular regurgitation; and less left ventricular outflow tract interaction reducing acquired atrioventricular block. The potential advantages over the balloon-expandable Sapien 3 include repositionability; no need for rapid ventricular pacing and the resultant hemodynamic disturbance; and lower risk of annular rupture (1).
The largest Portico valve experience to date is presented by Möllmann et al. (2) in this issue of JACC: Cardiovascular Interventions. This prospective, multicenter, nonrandomized study started in 2011, involved investigators with no prior Portico experience (including no run-in phase), and included 220 high or extreme operative risk patients (mean STS score 5.8 ± 3.3%) with severe aortic valve stenosis. The repositioning feature was used in ∼1/3 of patients. Despite this, 4 patients still required valve-in-valve due to incorrect position, possibly due to valve migration during final 20% deployment. Post-dilation was performed in ∼1/3 of patients. Ultimately, 96.8% of patients received a valve in the pre-specified correct location (1 to 9 mm below annulus). When taking into account post-procedure hemodynamics (aortic valve area >1.2 cm2, < moderate paravalvular leak), procedural success was 84.7%. Three patients died intra-procedurally, all due to left ventricular wire perforation.
Thirty-day outcomes were comparable to those seen in other transcatheter aortic valve replacement (TAVR) studies in high-risk or extreme-risk patients. The major outcomes most germane to TAVR—death (3.6%), stroke (5.4%), vascular complications (7.2%), pacemaker implantation (13.5%), and paravalvular leak ≥moderate (5.7%)—were similar to those seen in prior high-risk trials with the Evolut R (2.5%, 5.0%, 7.5%, 16.5%, 5.3%, respectively) and slightly worse in a high-risk trial with transfemoral Sapien 3 (1.6%, 1.4%, 5.5%, 13.5%, 3.4%, respectively) valves (3,4). Post-procedure aortic valve gradient averaged 8.3 ± 3.8 mm Hg (compared with Evolut R 7.8 ± 3.1 mm Hg and Sapien 3 11.4 ± 4.8 mm Hg). Prior concerns about high rates of valve thrombosis with the Portico valve were not manifest clinically in this study, and a recent study has shown this phenomenon occurs with other THVs, too (Portico 30%, Sapien 3 14%, Corevalve/Evolut R 6%) (5).
Although these early Portico results appear reasonable, by themselves, they do not suggest a major improvement in TAVR clinical outcomes is on the horizon. However, it is easy to imagine substantially better outcomes than those presented here with: 1) increased operator experience; and 2) the introduction of a second-generation Portico—with enhanced low-profile delivery, placement and stability features, and an outer sealing cuff (6). These developments should be reflected in the large trials currently underway. The pivotal PORTICO IDE randomized, controlled trial (Portico Re-sheathable Transcatheter Aortic Valve System US IDE Trial; NCT02000115) with 908 planned subjects will compare Portico versus different commercially available THVs, giving us fresh insight into comparable THV effectiveness. In addition, the Portico I prospective, nonrandomized trial (5 Year Observation of Patients With PORTICO Valves; NCT01802788) will enroll 1,024 subjects. Importantly, these trials have 5-year outcomes planned, giving us critical information about durability, as well as a cardiac CTA substudy designed to give us insight into subclinical valve thrombosis.
Should the Portico valve compare favorably to today’s commercially available THVs and become Food and Drug Administration approved, it will be the third or fourth valve, and the second self-expanding valve, on the U.S. market. This may result in enough competition to reduce THV cost, which is currently >3× a surgical valve. Although THVs current cost is >$30,000 in the United States, the cost in many countries in Europe, where multiple valves are available and costs have declined for several years is ∼$17,000 to $19,000 (7,8). Such a cost reduction could improve TAVR cost-effectiveness relative to surgical aortic valve replacement, especially important for lower-risk patients, and help drive increased TAVR availability.
In summary, the results of this study of the Portico valve support its continued investigation as a viable THV in today’s increasingly competitive THV market. With Portico comes the promise of increased ease of use, better understanding of subclinical valve thrombosis, improved patient outcomes, and wider TAVR availability. Let the ongoing trials continue.
↵∗ Editorials published in JACC: Cardiovascular Interventions reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Interventions or the American College of Cardiology.
Dr. Mavromatis has reported that he has no relationships relevant to the contents of this paper to disclose.
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