Medtronic has unveiled new two-year data from the high risk study of the CoreValve US pivotal trial, which continued to show superior survival benefit at two years for transcatheter aortic valve replacement (TAVR) with the CoreValve system compared to patients who underwent surgical aortic valve replacement (SAVR). Medtronic says that this is the first and only head-to-head study to show statistically significant survival differences favouring TAVR in aortic stenosis patients who are considered high risk for surgery.
Presented as a late-breaking clinical trial at the 64th Annual Scientific Session of the American College of Cardiology (14–16 March, San Diego, USA), the two-year outcomes from the CoreValve study found that the rate of all-cause mortality was significantly lower in TAVR patients than in the SAVR patients (22.2% vs 28.6%, p=0.04), with the absolute difference in all-cause mortality increasing between the two groups from 4.8% at one year to 6.5% at two years.
“CoreValve maintains a low and stable stroke rate and the recovery advantages CoreValve demonstrated at one year are maintained at two years. Current ACC/AHA guidelines refer to TAVR as a reasonable alternative to SAVR in high risk patients as judged by the heart team. However, these clinical data suggest a change in these guidelines may be warranted for the self-expanding valve in this patient population,” said Michael Reardon, professor of cardiothoracic surgery at Houston Methodist DeBakey Heart & Vascular Center, USA, and chairman of the patient screening committee of the CoreValve US pivotal trial. “I believe that the results of this randomised study suggest that self-expanding transcatheter valve therapy should be considered standard of care and preferred over surgery in this patient population.”
Using prospective evaluation, the rate of stroke was significantly lower in the TAVR group as compared to the SAVR group at two years (10.9% vs 16.6%, p=0.05), and the major stroke rates were comparable (6.8% vs 9.8%, p=0.25). The combined endpoint of all-cause mortality or major stroke significantly favoured the TAVR group (24.2% vs 32.5%, p=0.01).
Rates of major adverse cardiovascular and cerebrovascular events (MACCE) at one year were still superior at two years and were statistically lower in the TAVR group than the SAVR group (29.7% vs 38.6%, p=0.01). While the echocardiographic parameters of effective orifice area and mean aortic-valve gradient remained stable for both groups over the two year period, the TAVR group showed superior haemodynamics compared with the surgical group at all time points during the clinical trial follow-up (p=<0.001). Moderate to severe paravalvular regurgitation for the TAVR group at two years (6.1%) proved consistent with the low one-year rate.
The study randomised 747 severe aortic stenosis patients at 45 US centres to treatment with either CoreValve or open-heart surgery. The patients were estimated to have a predicted risk of operative mortality of 15% or higher at 30 days, assessed by two clinical site surgeons and confirmed by at least two surgeons on a National Screening Committee. The average age of patients in the study was 83.2 years old and the study enrolled a nearly equal number of men and women. In addition to the STS Predicted Risk of Mortality estimate of 7.4%, these patients had documented comorbidities, frailty and disability that placed them at increased risk for surgery.
CoreValve was approved by the US Food and Drug Administration (FDA) in 2014 for patients at extreme risk and high risk for surgery. Since receiving CE mark in 2007, CoreValve has been implanted in more than 75,000 patients in more than 60 countries.