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| Medtronic's CoreValve--Courtesy of Medtronic |
Medtronic's ($MDT) data dump at TCT revealed that commercial patients implanted with its CoreValve transaortic valve replacements (TAVRs) had similar outcomes to those in the device's pivotal clinical trial. The data is reassuring because in the real world, patients and clinicians are not under the same level of observation and scrutiny as they are during clinical trials.
Among 6,160 CoreValve patients in the TVT registry, run by the Society of Thoracic Surgeons and American College Cardiology, the rate of 30-day all-cause mortality was 5.2%, and the stroke rate was 2.6%. That's compared to 6.9% and 5% in the trial for FDA approval.
Other metrics revealed a similar pattern, according to release. Implantation was successful in 98% of commercial cases, (compared to 96.8% in the trial), 89.3% of patients were treated using the preferred transfemoral (through the leg) delivery route (compared to 77.3% in the trial), and the rate of valve- related readmissions was 1.5% (compared to 5.9% in the trial).
"It is reassuring to see that the profound clinical results in the U.S. CoreValve Pivotal studies were replicated among patients at high or extreme surgical risk in a 'real-world' clinical setting," said Dr. Jeffrey Popma in a statement. He was the co-principal investigator of the U.S. CoreValve pivotal trial, and presented the registry data at TCT. "The favorable results from the CoreValve analyses are likely attributable to operator experience, thoughtful patient selection, and effective education and training based on the 'Best Practices' learned in the U.S. Pivotal Studies, including the use of CT-based sizing. We believe that these results indicate that the CoreValve self-expanding bioprosthesis is safe and effective in patients with severe aortic stenosis unsuitable for surgery across a wide spectrum of U.S. medical centers."
The dataset consists of registry patients implanted with a CoreValve between FDA approval in January 2014 and March 2015. That means that it doesn't include patients who received Medtronic's third generation CoreValve Evolut R TAVR, which was FDA approved in June. The newest iteration can be retrieved and moved in reverse using its revamped delivery catheter once the valve is initially positioned, hopefully allowing cardiologists to make minor adjustments, resulting in fewer complications like paravalvular leak.
The data proves the value of not only the CoreValve, but of the TVT data registry as well. Information gleaned from the registry was used to expand the indication of Edwards' ($EW) Sapien TAVR to include additional access points, such as delivery of the device through the subclavian access point in the upper chest.
Now Medtronic and rival Edwards hope to use real-world data to expand the use of TAVR to include "intermediate risk" patients. TAVRs are currently implanted in high-risk elderly patients (with an average age around 81) who are too frail for open heart surgery.
Medtronic previously presented data of 995 high- and intermediate-risk commercial patients at the European Society of Cardiology conference. The study found the intermediate risk group had lower three-year mortality (28.6% to 45.9%), and comparable rates of major stroke (3.3%) and major vascular complications (12.1%), as compared to the high-risk group. Edwards presented similar data in the spring at the American College of Cardiology and EuroPCR conferences.
TAVRs have produced excellent clinical and financial results for industry (chiefly Medtronic and Edwards) as well as elderly and frail heart disease patients who had no other treatment options.
Concerns about reduced leaflet mobility stemming from the clinical trial of St. Jude's ($STJ) Portico TAVR threaten to diminish their strong safety record. A study in the New England Journal of Medicine said the mechanical issue occurs in various TAVRs (as well as traditional surgical aortic valve replacements), and found a tentative correlation between the phenomena and the incidence of stroke.
But the study's lead author, Dr. Raj Makkar, said at TCT that the mainstream media overplayed the potential safety issue. Following the article's publication, the FDA immediately put out a statement saying reduced leaflet mobility is of unknown clinical significance. The mechanical issue is unlikely to change clinical practices, at least in the short run.
- read the release