SAN FRANCISCO – Transcatheter aortic valve replacement with the self-expanding CoreValve in patients at extreme surgical risk significantly reduced the rate of death or major stroke at 1 year, from 43% to 26%, in a 487-patient pivotal trial.
The CoreValve Extreme Risk study gathered data from a registry of patients with symptomatic severe aortic stenosis who attempted an iliofemoral implantation procedure with the CoreValve at 40 U.S. sites. Results were compared with an "objective performance goal" derived from two sources: a meta-analysis of five contemporary balloon valvuloplasty series that found a 43% mortality and major stroke rate at 1 year, and the 1-year rate from the PARTNER B trial in inoperable patients (Placement of Aortic Transcatheter Valves, Cohort B), which was 50% but had a lower confidence bound of 43%.
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The performance-goal comparison was necessary in the current study because randomizing these patients to medical therapy in a control group is no longer an acceptable option in the United States, Dr. Jeffrey J. Popma said at the Transcatheter Cardiovascular Therapeutics annual meeting.
The 1-year all-cause mortality rate was 24%, and the cardiovascular mortality was 18%, reported Dr. Popma, professor of medicine at Harvard Medical School, Boston.
Two percent of patients developed a major stroke within 1 month and 4% did so within 1 year.
Data from a continued access study involving another 830 extreme-risk patients who received the CoreValve through an iliofemoral approach are showing even better results, with a 16% rate of mortality or major stroke at 6 months, he added.
Among secondary endpoints at 1 year in the main study, 7% of patients developed any kind of stroke, 2% had an MI, 2% need reintervention, 41% had bleeding that met Valve Academic Research Consortium criteria, 8% had major vascular complications, and 27% required implantation of a permanent pacemaker, Dr. Popma reported at the meeting, cosponsored by the American College of Cardiology. Ninety percent of patients improved by at least one New York Heart Association functional class and 60% improved by at least two classes at 1 year of follow-up.
Dr. Jeffrey Popma
Paravalvular regurgitation of any severity was seen in 53% of patients 1 month after implantation and in 33% at 1 year. Moderate paravalvular leakage (PVL) affected 9% at 1 month and 4% at 1 year, and severe PVL affected 1.6% at 1 month and no patients at 1 year, Dr. Popma said. Among the 11% of patients with moderate PVL at 1 month, 80% of those who survived to 1 year had a reduction in leakage over time.
"We believe that’s why we did not find an association in the study between mild or moderate aortic regurgitation with respect to late-term mortality," though mortality risk was substantially higher with severe regurgitation, he said. One-year mortality rates were 86% with severe PVL and 24% with either moderate or mild PVL, compared with 18% in patients with no PVL.
The improvement in PVL rates over time may be due to use of CT angiography to select appropriate valve sizes for patients and continued expansion of the self-expanding frame over time. "That’s a remarkable finding, and it needs to be confirmed," Dr. Popma said.
The study focused on patients whose severe frailty, comorbidity, or disability put them at extreme risk of at least a 50% chance of death or irreversible morbidity within 30 days had they undergone surgical aortic valve replacement. A second U.S. pivotal trial of the CoreValve is focusing on patients at high (but not extreme) risk.
Most of the sites in the study had no experience with CoreValve before this study, Dr. Michael J. Mack noted at a press briefing. "The results are outstanding, but especially putting it in that light," said Dr. Mack, director of cardiovascular disease for the Baylor Scott & White Health System, Dallas, and a member of the steering committee for the PARTNER trial.
Dr. Popma reported financial associations with Medtronic, which sponsored the study and makes CoreValve, and with six other companies.
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