Expanded Use Study Presented for Medtronic's CoreValve TAVR System

October 13, 2015—Medtronic plc announced new data that show positive clinical outcomes at 1 year for the CoreValve transcatheter aortic valve replacement (TAVR) system in new patient populations with significant comorbidities. Results from three patient populations evaluated within the CoreValve United States Expanded Use Study were presented at TCT 2015, the 27th annual Transcatheter Cardiovascular Therapeutics scientific symposium being held October 11-15 in San Francisco, California.

The three populations included patients with a degenerated surgical bioprosthesis, patients with end-stage renal disease (ESRD), and patients with low-gradient aortic stenosis (LG-AS). In March 2015, the CoreValve system was approved in the United States for valve-in-valve procedures in both high- and extreme-risk patients with failed surgical valves. TAVR is not approved for the latter two patient populations.  

In the company’s press release, Michael Reardon, MD, commented, “It’s encouraging to see patients benefitting from the CoreValve system, many of whom have been unable to receive treatment due to these severe comorbidities. When treated with the CoreValve system, not only do these patients live longer, they are able to achieve and maintain a good quality of life, which is really important for these individuals and their loved ones.” Dr. Reardon, who is Professor of Cardiothoracic Surgery at Houston Methodist DeBakey Heart & Vascular Center in Houston, Texas, served as chairman of the patient screening committee of the CoreValve United States Pivotal Trial.

Medtronic reported that the new data on valve-in-valve procedures in 109 patients with failed surgical valves in the expanded use study showed a low rate of all-cause mortality (13.4%) and major stroke (3.1%) at 1 year. These rates included patients with small surgical valve sizes (17-mm inner diameter) who had not been previously studied. 

All patients demonstrated a statistically significant improvement in quality of life as measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), with an average improvement of 31.8 points at 1 year (P < .001) on the 100-point scale. Additionally, 93.6% of the initial 109 patients were in New York Heart Association (NYHA) class III and IV at baseline, and in the surviving patients at 1 year, 73.2% were in NYHA class I.

Patients in the valve-in-valve study also experienced a low rate of moderate aortic regurgitation (6.4%) with no cases of severe regurgitation (0%), and benefitted from strong hemodynamic performance with a mean gradient of 16.5 mm Hg at 1 year, despite placement within small surgical valves.

Dr. Reardon stated, “In valve-in-valve procedures, the CoreValve system’s unique supra-annular design helps maximize blood flow through the aortic valve, which is particularly important when implanting within a surgical valve where the original orifice area is often compromised. TAVR provides physicians with an alternative treatment option for patients facing another open heart surgery.”

The ESRD subset from the expanded use study included patients who also showed a low rate of mortality and stroke. The company stated that despite the clinical challenges of treating this patient population, CoreValve exceeded the objective performance goal for all-cause mortality or major stroke set out in the original CoreValve Extreme Risk Study (30.3% in this population vs the objective performance goal of 43% in the United States pivotal extreme-risk trial). Additionally, the rate of all-cause mortality among the patients with ESRD in the expanded use study was lower than that of patients undergoing dialysis in the Transcatheter Valve Therapy Registry (30.3% vs 41%). Patients with ESRD also showed a significant improvement in quality of life at 1 year with an average increase in the KCCQ overall summary score of 27.5 points compared to baseline.

In the LG-AS patient population within the expanded use study, results were also comparable to the CoreValve Extreme Risk Study. Patients with LG-AS treated with the self-expanding valve had a low rate of all-cause mortality or major stroke regardless of whether they had LG-AS with normal ejection fraction (26%, n = 113) or LG-AS with low ejection fraction (26.3%, n = 46). The KCCQ score confirmed the patients' improvement in quality of life at 1 year with average improvements of 25.8 points for patients with normal ejection fraction and 30.5 points for those with low ejection fraction.

Medtronic advised that the CoreValve TAVR system is approved by the US Food and Drug Administration for treatment of patients at extreme risk and high risk for surgery. The CoreValve system is not approved in the United States for patients with ESRD or LG-AS. The device received European CE Mark approval in 2007. The company’s CoreValve Evolut R system was recently approved in Europe.