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Registry data depict evolution of TAVR use
Two studies published in the Journal of the American College of Cardiology have documented the nationwide changes in clinical outcomes and overall patterns of use of transcatheter aortic valve replacement as experience with the procedure grows in the United States and France.
“For any new interventional technology in medicine, no one could question the beneficial role of experience in improving both results and clinical outcomes. The more you do, the better you are. If this is true for any well-established interventional cardiology procedure, it is particularly relevant with regard to TAVR,” Alain Cribier, MD, Eric Durand, MD, and Helene Eltchaninoff, MD, all from the University Hospital Charles Nicolle and Normandie University Rouen UNIROUEN in France, wrote in an accompanying editorial.
FRANCE TAVI, FRANCE 2
In one study, Vincent Auffret, MD, MSc, from the Cardiology and Vascular Diseases Service, Pontchaillou University Hospital Center, Rennes, France, and colleagues compared data from two French registries to track clinical practice trends from 2010. The FRANCE TAVI registry captured data on TAVRs performed on 12,804 patients from 2013 to 2015 at 48 centers in France, and the FRANCE 2 registry included data on all TAVRs performed on 4,165 patients from 2010 to 2012 at 34 centers.
Of all patients included in both registries, the median age was 85 years and about half were men. Overall, patients in FRANCE TAVI vs. FRANCE 2 were older, had lower surgical risk (median logistic EuroSCORE, 15% vs. 18.4%; P < .001) and were less likely to have coexisting conditions or severe symptoms. From FRANCE 2 to FRANCE TAVI, there was also an increase in the proportion of patients with previous surgical AVR (1.7% vs. 4.4%; P < .001).
Transfemoral access became more common from FRANCE 2 to FRANCE TAVI and was used in more than 80% of patients in the latter registry. Furthermore, among hospitals that participated in both registries, the use of transapical access declined from 27.9% in 2010 to 4.7% in 2015 (P < .001).
Although most procedures were performed in cath labs, a shift favoring hybrid operating rooms was noted from FRANCE 2 to FRANCE TAVI (15.8% vs. 35.7%; P < .001). Transesophageal echocardiography guidance also declined from 60.7% to 32.3%, and, among centers that participated in both registries, the researchers observed a decrease from 70.3% to 47.2% in use of general anesthesia for the procedure.
The rate of device success, defined using Valve Academic Research Consortium criteria, increased from 95.3% in FRANCE 2 to 96.8% in FRANCE TAVI (P < .001), according to the data.
In terms of clinical outcomes, in-hospital mortality was lower in FRANCE TAVI vs. FRANCE 2 (4.4% vs. 8.1%; P < .001), as was 30-day mortality (5.4% vs. 10.1%; P < .001).
The rate of stroke and other complications, such as annulus rupture, aortic dissection and valve migration remained stable, but cardiac tamponade increased during the study period. Importantly, the researchers noted, from FRANCE 2 to FRANCE TAVI, permanent pacemaker implantation also increased from 12.6% to 17.5% (P < .001).
“These [in-hospital and 30-day mortality] rates compared favorably with those of FRANCE 2 and probably reflected a more refined selection of lower-surgical risk patients, improved procedural planning and execution, newer iterations of transcatheter devices, and enhanced postprocedural care,” the researchers wrote. “Nonetheless, given that TAVR indications are likely to expand officially to lower-surgical risk patients, concerns remain regarding rare but potentially life-threatening complications and [pacemaker implantation] that should be addressed in future studies.”
STS/ACC TVT Registry
In the second study, John D. Carroll, MD, from the division of cardiology, department of medicine, University of Colorado Denver, Aurora, and colleagues evaluated the link between increasing experience with TAVR and clinical outcomes using data on 42,988 procedures performed at 395 hospitals participating in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry from 2011 to 2015. To specifically assess the relationship between center volume and outcomes, the researchers used a case sequence approach.
Results revealed an association between increasing center volume and lower in-hospital risk-adjusted outcomes, such as mortality (P < .02), vascular complications (P < .003) and bleeding (P < .001). However, the same association was not observed for stroke (P = .14).
Additionally, in the volume-outcome model, from the first case to the 400th case, the researchers found that mortality decreased from 3.57% to 2.15%, bleeding from 9.56% to 5.08%, vascular complications from 6.11% to 4.2% and stroke from 2.03% to 1.66%.
The data denoted a nonlinear relationship between volume and vascular and bleeding complications in which risk for adverse events was higher in the first 100 cases.
The researchers also identified an association between procedure volume and vascular and bleeding complications in patients who underwent TAVR with transfemoral access.
“These results can inform decisions regarding optimizing this transformational, expensive, and rapidly growing treatment for aortic valve disease in the U.S. health care system. Sustaining the specialized, experienced center model for heart valve therapy is supported by these data,” the researchers wrote.
‘A steep learning curve’
In their editorial, Cribier, Durand and Eltchaninoff celebrated the expansion of TAVR and improvement in outcomes in Europe and the United States, as evidenced by the data. They noted that from its introduction, “a steep learning curve” was expected for the technology.
“With growing experience, marked technological and procedural advances, enhancement of training and proctorship programs, and closer collaboration between experienced and new centers, one could expect a drop in the learning curve process over the last decade,” they wrote. “However, despite our extensive personal experience of TAVR since 2002, we must humbly confess that our learning curve is still ongoing, case after case, reactivated by each of the unceasing technological and procedural refinements.”
These registries, they noted, will continue to provide important data, especially with the possibility of TAVR expanding to low-risk or younger patients.
“In 2017, we are far from the end of the TAVR’s odyssey and the potential of this disruptive technology remains explosive. If we believe our crystal ball, in 2022, for the 20th anniversary of TAVR, new reports in the Journal will confirm TAVR as the predominant therapy for the treatment of patients with severe aortic stenosis,” they wrote. – by Melissa Foster
References:
Auffret V, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.04.053.
Carroll JD, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.04.056.
Cribier A, et al. J Am Coll Cardiol. 2017;doi:10.1016/j.jacc.2017.05.008.
Disclosures: Edwards Lifesciences and Medtronic partly funded the FRANCE TAVR registry. Auffret reports receiving research grants from Abbott, Biosensors, Boston Scientific, Edwards Lifesciences, Medtronic and Terumo. Carroll reports being a local site investigator in TAVR studies sponsored by Edwards Lifesciences and Medtronic. Please see the full studies for a list of the other researchers’ relevant financial disclosures. Cribier reports serving as a consultant and proctor for Edwards Lifesciences. Durand reports receiving lecture fees for Edwards Lifesciences. Eltchaninoff reports receiving lecture fees and serving as a proctor for Edwards Lifesciences.
Perspective
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In the first study conducted by Auffret and colleagues, the investigators prospectively evaluated data on TAVRs performed at 48 centers across France from 2013 to 2015 in the FRANCE TAVI registry and compared those with data from the FRANCE 2 registry, which captured all TAVRs performed from 2010 to 2012 across 34 centers. FRANCE TAVI participants were older; their surgical risk was lower; the majority underwent transfemoral TAVR; and they had higher Valve Academic Research Consortium (VARC)-defined device success.
Although moderate to severe aortic regurgitation and in-hospital and 30-day mortality were significantly lower in recent years, stroke and potentially life-threatening complications, such as annulus rupture or aortic dissection, remained stable over time. The findings of this study are consistent with most practices in the United States, which are also seeing a shift in baseline characteristics of patients undergoing TAVR to include those who are older but have fewer comorbidities.
The lower rate of in-hospital and 30-day mortality is potentially related to an improved heart-team approach for patients with severe aortic stenosis, better care after TAVR, newer and better versions of transcatheter valves and smaller delivery systems. However, despite improved mortality, the rates of tamponade and pacemaker implantation significantly increased in recent years. The post-TAVR pacemaker rate has increased significantly (12.6% vs. 17.5%, P < .001) in FRANCE TAVI. This is concerning given that TAVR is set to expand to low-risk patients and potentially younger patients as well. As noted by the investigators, the pacemaker implantation will prolong hospital stay and might compromise the cost-effectiveness of TAVR. More importantly, the cardiac complications associated with long-term pacing, including tricuspid valve regurgitation, left ventricular dyssynchrony, right ventricular failure and more, require careful attention and suggest a need to focus on strategies to reduce these complications.
The second study conducted by Carroll and colleagues also provides interesting data. Aortic valve stenosis is a condition that is associated with age due to the major etiology of aortic stenosis being degenerative with onset at an advanced age. With more patients with severe aortic stenosis, TAVR volume is expected to increase with the major incursion of the baby-boomer generation with its advancing age.
In this study, the investigators address a very important question related not just to the competency of the operators performing TAVR but to the institutions promoting the procedure as well. Greater operator experience and institutional volume have been shown in several areas to be associated with better procedural outcomes. This very large, retrospective, observational study extends those observations to patients undergoing TAVR.
After an initial steep learning curve over the course of approximately 100 cases, outcomes improved with higher procedural volumes, reflected by lower rates of mortality, bleeding and vascular complications, regardless of patient factors, date of procedure and device iterations. Beyond 100 cases, procedural risk continued to decline but at a more gradual rate.
Although data in this study cannot be extrapolated to determine whether a significant volume–outcome relationship will persist after operators and sites have achieved progressively more experience, there remains an incentive to concentrate procedural experience in discrete heart valve centers. The findings of this study will help professional societies currently updating recommendations of institutional and operator requirements for TAVR.