SOURCE Registry Data Published: TAVI Stays Strong at 1 Year

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Transcatheter aortic valve implantation (TAVI) produces “excellent” 1-year survival in high-risk and inoperable patients, according to a report from the SOURCE registry published online July 11, 2011, ahead of print in Circulation. Not only do the findings indicate that outcomes improved compared to historical registries, they can also serve as a point of comparison for future TAVI studies.

One-year data from the SOURCE (Edwards Sapien Aortic Bioprosthesis European Outcome) registry were previously presented at EuroPCR 2010 in Paris, France.

Solid Outcomes, Even in Transapical Patients

The SOURCE registry, led by coprincipal investigators Martyn Thomas, MD, and Olaf Wendler, MD, both of King’s Health Partners (London, United Kingdom), sought to assess initial results of TAVI with the Edwards Sapien valve (Edwards Lifesciences; Irvine, CA) during its first years of commercial use in Europe. Cohort 1 of the study enrolled 1,038 consecutive patients at 32 centers. Among them, 463 were treated via transfemoral access and 575 via transapical access, the latter route characterized by comparatively higher risk at baseline (mean logistic EuroSCORE 29% vs. 25.8%; P = 0.007).

Kaplan-Meier curves indicated 1-year survival rates of 76.1% overall, 72.1% in the transapical group, and 81.1% in the transfemoral group. These results stand up well against earlier findings—pooled from the REVIVE, REVIVAL, TRAVERCE, and PARTNER EU registries—which showed survival curves of 58.1% and 74.9% in transapical and transfemoral patients, respectively, who were treated between January 2006 and January 2008. Moreover, most SOURCE subjects who survived to 1 year (73.5%) were New York Heart Association Class I or II.

Of the 179 deaths that occurred between 30 days and 1 year, only one quarter (25.1%) were cardiac-related, while nearly half (49.2%) were noncardiac and another quarter (25.7%) were classified as unknown. The most frequent causes of noncardiac death were pulmonary disease (23.9%), renal failure (12.5%), cancer (11.4%), and stroke (10.2%).

Multivariable analysis linked logistic EuroSCORE, renal disease, liver disease, and smoking to higher mortality but found carotid artery stenosis, hyperlipidemia/hypercholesterolemia, and hypertension were all associated with better survival.

“The 1-year results of Cohort 1 of the SOURCE registry provide a benchmark against which future TAVI cohorts and new TAVI devices may be measured,” the authors conclude.

In an e-mail communication with TCTMD, Dr. Thomas said SOURCE indicates that “even with the first-generation device using a 22-Fr and 24-Fr sheath, TAVI can be safely introduced into clinical practice with 1-year survival greater than 80% in transfemoral patients. . . . It can be hoped that results will improve still further in the SOURCE XT Registry, which is testing the latest generation 16-Fr and 18-Fr devices in Europe. Already more than 1,000 patients have been enrolled.”

One task, he said, will be to reduce major vascular complications, which increase mortality. Dr. Thomas added that the newer TAVI devices might overcome this issue.

Good News Keeps Getting Better

As more and more results have come out of the original SOURCE registry, the message has been consistently positive, said Ted Feldman, MD, of Evanston Hospital (Evanston, IL). At EuroPCR 2011 in Paris, France, researchers presented data that extended follow-up to 2 years and stratified the early and later experience with the Sapien valve.

“One of the big messages in the comparison of the first several hundred patients and next several hundred patients is that the outcomes have been very stable in terms of iliofemoral bleeding complications, early mortality, and such [while] the number of comorbidities has gone up in the population,” he told TCTMD in a telephone interview. SOURCE demonstrates that as experience has grown, TAVI has performed well even in very elderly and sick patients, he added.

Dr. Feldman was similarly positive about the shift in the results seen for transapical patients.

“Transapical outcomes have improved in SOURCE as they have, I hope, for most sites doing this procedure, because of patient selection. The patients who find their way to consideration for transapical are those who don’t have adequate iliofemoral access for percutaneous [intervention], and it’s clearly a sicker group,” he said. “Within that group, selecting those who are going to be able to recover is a great challenge. . . . [I]n our own experience it’s been frailty that’s really defined the difference between the patient who bounces back after transapical and the patient who languishes.”

Moving forward, it will be important to develop more quantified assessments of frailty, particularly for use in transapical patients, Dr. Feldman advised.

Dr. Thomas agreed that transapical results have “dramatically improved with time.” However, he credited the learning curve of physicians for the shift.

Optimizing Patient Selection

In the overall cohort, mortality risk of open cardiac surgery was gauged according to the logistic EuroSCORE and Society of Thoracic Surgeons score, the paper notes, adding “unfortunately their utility in TAVI is very much open to question, resulting in an urgent need to produce a TAVI risk score that will have a similar utility for TAVI patients.” The SOURCE XT registry is working toward this goal, Dr. Thomas said.

One thing to keep in mind “with these various tools,” Dr. Feldman suggested, “is whether they’re being used for patient selection or prognosis. . . . I think the discussions have to be sharpened up a bit [about which one of these is the objective].”

FDA Panel Decision Looms Large

Next week on July 20, a US Food and Drug Administration advisory panel will debate whether to recommend that the agency approve TAVI with the Sapien device.

Although it is difficult to predict exactly what the panel will discuss, Dr. Feldman cautioned, “I think the FDA is going to be considering primarily [the US-based] PARTNER data, because the process of patient selection in PARTNER is so well-defined and in SOURCE is less defined and because the adjudication of outcomes in PARTNER is rigorous beyond any other experience reported anywhere. The importance of SOURCE for the FDA discussion is demonstrating that in practice much less regulated than in something like the PARTNER trial, outcomes are as good or better. So I think it has a lot of value. I hope it can be emphasized.”

Dr. Feldman elaborated on how the different patient populations in PARTNER and SOURCE played out in the real world.

“In PARTNER, there were many patients who didn’t meet inclusion criteria and got turned away from catheter therapy for their aortic stenosis and who also don’t get operated on even though by the strictest definition they are ‘operable,’ because they are frail or very elderly. Simply being referred for evaluation in PARTNER often means they’ve been turned down in community practice. And it’s sort of a tragedy that PARTNER has left a gap between real surgical practice in the United States and those patients who are treated with TAVI,” he explained. “SOURCE includes many, many more of that group and demonstrates [that TAVI can achieve good outcomes].”

 

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Source:
Thomas M, Schymik G, Walther T, et al. One-year outcomes of cohort 1 in the Edwards SAPIEN Aortic Bioprosthesis European Outcome (SOURCE) registry: The European registry of transcatheter aortic valve implantation using the Edwards SAPIEN valve. Circulation. 2011;124:425-433.

 

 

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• PARTNER Cohort A Published: Surgical Candidates Obtain Similar 1-Year Survival with TAVI, Surgery
• SOURCE Registry Data Fail to Produce Useful TAVI Risk Score