Author + information
- Published online March 6, 2017.
- aDepartment of Surgery, University of Virginia, Charlottesville, Virginia
- bCardiology Department, Bichat Hospital, Assistance Publique-Hôpitaux de Paris, Département Hospitalo-Universitaire Fibrosis, Inflammation, Remodeling in Cardiovascular, Respiratory and Renal Diseases, Paris-Diderot University, Paris, France
- ↵∗Address for correspondence:
Dr. Gorav Ailawadi, Department of Surgery, University of Virginia, P.O. Box 800679, Charlottesville, Virginia 22908.
- procedural outcomes
- procedural risk
- transcatheter mitral clip
- transcatheter valves
- valve in valve
The report from The Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry (1), in this issue of the Journal, highlights the culmination of a ground-breaking collaboration among cardiologists, surgeons, and the U.S. Center for Medicare & Medicaid Services (CMS). This annual report now includes >54,000 transcatheter aortic valve replacement (TAVR) procedures and >3,700 transcatheter mitral repair (MitraClip, Abbott Vascular, Santa Clara, California) procedures since commercial approval in the United States.
This powerful registry was creatively designed to fulfill CMS requirements for hospitals to receive payment, while functioning as a post-market approval database to follow nationwide volumes and outcomes. This “real-world” registry captures all procedures performed in the United States, thus avoiding selection bias other than Food and Drug Administration (FDA) label. Moreover, data quality is audited with evidence of >85% accuracy. Other nationwide registries including all TAVR procedures have also been reported in Europe (2–4). These prospective registries are essential to evaluate new procedures, because they capture patient characteristics and endpoints not available in administrative databases on the basis of hospital discharge codes. As such, the institution of such registries represents a considerable workload, and the organizers of the STS/ACC TVT Registry should be congratulated for the quality of their database, in particular the low rate of missing data.
Transcatheter Aortic Valve Replacement
Patients undergoing TAVR reflect current indications, including symptomatic patients with aortic stenosis at high or inoperable risk for conventional surgical aortic valve replacement. Patients were similar to those seen in other nationwide registries, with a median age of 83 years and an STS risk score of 6.5% with multiple additional reasons for high risk/inoperable status, including frailty in >50% of patients. Despite a similar median age each year, the STS PROM (Predicted Risk of Mortality) decreased slightly each year. It is important to note that during this time period, the registry only included high-risk and inoperable patients. Recent reports documenting the superiority of TAVR over surgical aortic valve replacement in intermediate-risk patients have led to commercial approval in this risk group in the summer of 2016 (5). Thus, future annual TVT reports will include a younger, healthier population than presented here.
With respect to mortality, the 5.7% 30-day mortality still remains better than the STS 30-day predicted mortality risk of 6.5%. As in other large series, the 30-day mortality decreased over time from 7.5% in 2012 to 4.6% in 2015. The reasons for this continued improvement is likely a multitude of factors, including newer-generation valves, smaller delivery sheaths, increased center experience, and improvements in patient selection (6,7).
There are other notable trends. First, the use of the transfemoral approach was 71%, similar to the 71% to 73% rates in European series (2,3). Use of the transfemoral approach increased yearly, likely due to the introduction of smaller-caliber femoral delivery systems. Further, there is gradually increasing use of monitored sedation instead of general anesthesia, most dramatically in 2016. The stroke rates are exceedingly low, and the paravalvular leak rates have continued to improve, potentially as a result of more accurate sizing and device selection. Finally, there has been an increasing need for pacemakers, potentially due to the rising use of self-expanding valves; this trend needs to be followed, particularly as we are considering using this disruptive technology in lower-risk patients.
As noted by Grover et al. (1), the STS/ACC TVT Registry has potentially allowed earlier device approval with close post-market surveillance. The 1-year mortality of >20% remains high in this population and is likely related to comorbidities. Nevertheless, device failure does not appear to be occurring at 1 year. Trends in complications may be detected at an earlier stage with systematic monitoring in registries. Another use of the registry is benchmarking and quality control of TAVR centers. The predictive performance of risk scores aimed at assessing 30-day mortality after TAVR is not optimal, even when considering multivariable scoring systems specifically developed and validated in TAVR populations (6,7). Therefore, particular caution will be needed when comparing results between centers adjusted on the level of risk scores. Nevertheless, the development of a TVT TAVR mortality model is a huge step forward in the evaluation of patients being considered for TAVR. With ongoing refinements, the accuracy of these predictive models will likely improve.
The TAVR story is a fantastic success not only due to the rapid acceptance of such technology within 15 years after the first-in-man procedure, but also because it triggered a revolution in catheter-based valve procedures. We now have several, large randomized trials that allow guidelines to have high levels of evidence, which was not usual in the field of heart valve diseases. Continuous follow-up even beyond 1 year is necessary to provide unbiased information on the durability of valves, which is of utmost importance when considering the extension of indications of TAVR toward patients who are at lower risk and have long life expectancies. The evaluation of the durability of valvular substitutes requires serial echocardiographic assessments, which represents an additional challenge for large registries.
Transcatheter Mitral Valve Repair
The number of transcatheter procedures performed to treat mitral regurgitation (MR) on native valves is markedly lower than the number of TAVR procedures. This is the consequence of the more recent approval of the MitraClip and, more importantly, of indications restricted to primary MR in prohibitive surgical-risk patients with appropriate anatomy. The 3,745 procedures reported in the STS/ACC TVT Registry represent the largest reported experience in transcatheter treatment of primary MR. Although the MitraClip has been available in Europe, it has been used more commonly for secondary MR (8). Although the treatment efficacy for secondary MR is an appealing indication due to the frequent high-risk profile of patients, it remains to be proven by ongoing randomized trials in the United States, and thus, is not an FDA-approved indication. The rates of 2.3% for in-hospital mortality and 5% for 30-day mortality rate are consistent with other European registries, despite the median age being roughly 10 years older in the United States. The rate of residual significant MR (15% with 3+ or 4+) remains a limitation of transcatheter mitral valve repair (TMVR) compared with surgery. Although this is not a major drawback when considering patients who are at high risk for surgery, it certainly limits the enthusiasm for considering TMVR in lower-risk patients. It should also be noted that the degrees of residual MR, which can be challenging to assess by echocardiogram, are site-reported and not adjudicated. Nevertheless, the safety profile of TMVR remains excellent across the United States. A more in-depth analysis of TVT outcomes with TMVR is forthcoming.
Finally, the TVT report included 349 transcatheter mitral valve-in-valve and valve-in-ring procedures. Thus far, the limited experience is due to: 1) a lack of FDA approval, and 2) the fact that devices were not designed for the mitral position. The overall outcomes are respectable nevertheless, with better than expected 30-day mortality (8.5%) compared to a predicted STS score of 11%. The incidence of outflow tract obstruction was exceedingly low. Given the limited experience and the lack of long-term follow-up, it is reasonable to restrict these procedures to high-risk patients. Notably, the number of these procedures may be under-reported, as sites may not be reporting all patients in the TVT Registry because this is not an approved indication for these valves.
In summary, the TVT Registry is an impressive feat of collaboration that has and will provide valuable information on volumes and 1-year outcomes. The most critical piece is data quality, which has been improving but is still the limitation of any such registry. Finally, as these technologies become more widespread with increasing use in healthier patients, longer-term follow-up will be necessary.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Ailawadi has served as a consultant for Abbott Vascular, Edwards Lifesciences, St. Jude Medical, Medtronic, and Atricure. Dr. Iung has served as a speaker for Edwards Lifesciences.
This article is copublished in the Journal of the American College of Cardiology and The Annals of Thoracic Surgery.
- American College of Cardiology Foundation and The Society of Thoracic Surgeons
- Grover F.L.,
- Vemulapalli S.,
- Carroll J.D.,
- et al.,
- for the STS/ACC TVT Registry
- Ludman P.F.,
- Moat N.,
- de Belder M.A.,
- et al.
- Walther T.,
- Hamm C.W.,
- Schuler G.,
- et al.
- Gilard M.,
- Eltchaninoff H.,
- Donzeau-Gouge P.,
- et al.
- Iung B.,
- Laouenan C.,
- Himbert D.,
- et al.
- Edwards F.H.,
- Cohen D.J.,
- O'Brien S.M.,
- et al.
- Nickenig G.,
- Estevez-Loureiro R.,
- Franzen O.,
- et al.