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Encouraging data for percutaneous heart valve replacements
Encouraging data for percutaneous heart valve replacements New research has shown that advancements in catheter design may reduce the rate of vascular complications and adverse events in patients receiving transfemoral aortic valve replacements. The data was presented at the recent Transcatheter Cardiovascular Therapeutics (TCT) meeting in Washington, DC.
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Leon, Columbia University Medical Center, NYC, retrograde transfemoral transcatheter aortic valve replacement can be performed with acceptable mortality in high risk aortic stenosis patients. Leon presented the pooled results of 243 patients treated with the Edwards Sapien transcatheter heart valve, the REVIVE II (n=90), the REVIVAL (n=55) and the Canadian special access (n=99). Feasibility studies REVIVE II and REVIVAL II are similar feasibility studies taking place in Europe and North America. The primary endpoints are death, myocardial infarctions (MIs), stroke or urgent cardiac surgery at 30 days, three, six, and 12 months. Canadian Special Access is a compassionate-use study using similar procedural technique and follow- up protocol to the other two studies. Leon explained that pooled data showed the average age was 83.2 years, with 47% women and 53% men. Patients included were those with severe aortic stenosis and were at high risk for surgery. Thirty-four percent of patients had undergone prior surgery, and 28% had chronic obstructive pulmonary disease. Leon reported that freedom from death at one year was similar across the entire population (73.0%, REVIVE II; 73.8%, Canada; and 74.7%, REVIVAL II). The clinical outcomes included 63 major adverse cardiac events: 51 deaths (12% in the first 30 days), seven MIs and 14 strokes. “Neurologic and vascular complications remain frequent,” he said. “These are things we should work on for the future.” However, he noted that the mortality rate in these high risk patients was acceptably low. In the study, the device used was the RetroFlex Total Heart Valve Delivery System (Edwards Life Sciences). Using EuroScore, it was discovered that almost one quarter of patients had a risk profile less than 20%, and 54% had a logistic EuroScore of 20% to 40%. Leon said EuroScore is difficult to use as an absolute risk profile score because it does not capture all the variables. Leon and his team demonstrated an 88% implant success rate and 26 unsuccessful deployments, including failed vascular access in ten patients. According to Leon, “Long-term survival in this patient population is limited by their comorbidities. It should be a core consideration as we plan clinical trials in these patients and improvements in catheter design may decrease some of these complications, particularly the vascular complications and maybe even the stokes, and further improve survival.”
Transapical aortic valve replacement is promising Dr Todd Dewey, Cardiopulmonary Research Science and Technology Institute, Dallas, TX, presented a pooled analysis of three different trials investigating transapical aortic valve replacement. Dewey explained that the trials demonstrated a durable 13mmHg reduction in peak gradient for 23mm and 26mm valves. The researchers reported overall survival rate at one year among patients enrolled in the REVIVAL II (transapical), TRAVERCE, and Canadian Special Access trials was 65%. However, the latest data on long-term survival was reportedly 80% at Leipzig, Germany, the site of the TRAVERCE study. According to Dewey, this indicates that with product improvements, better patients outcomes will follow. “Part of this is a learning curve and patient selection,” he said. “We are a little bit more facile and more efficient with the procedure, and we are also selecting the patients a little bit better – who should get the procedure and who shouldn’t.” Early results In the analysis, data on 217 patients were included. Risk-stratified survival curves from REVIVAL II and TRAVERCE were not significantly different, said Dewey. All-cause mortality rates were worse for patients with a EuroSCORE ≥40 and about the same for scores between 20 and 40 compared with ≤20). Transapical aortic regurgitation occurred in some patients, and in TRAVERCE (n=125), the majority of procedures were performed off-pump (71.2%) with a total procedure time of two hours and seven minutes. Transapical peak gradients at baseline for both valve sizes were 73mmHg, decreasing to 13.4mmHg at discharge or seven days postprocedure. The gradient stayed consistent, and at one year follow-up, averaged 13mmHg. Dewey said that ejection fraction was 52% at baseline and increased slowly to 61% at one year.
Edwards THV overview With nearly 600 implants worldwide and the only company with an investigational Device Exception approval for a US randomised pivotal trial, Edwards has the largest clinical experience. Early clinical results from the US trial demonstrated only a 7.4% 30-day mortality rate, which is favourable when compared to other devices’ 30-day mortality rates. CoreValve system Preliminary results from the International Safety and Efficacy Studies of Percutaneous Aortic Valve Replacement show that the CoreValve 21F and 18F ReValving system is safe and effective for treating high risk aortic stenosis patients. The results were reported by Dr Jean- Claude Laborde, Clinique Pasteur, Toulouse, France. According to Laborde, over the last year, percutaneous aortic valve replacement with the CoreValve system has evolved into a purely transcatheter procedure with high rates of procedural success and good shortterm outcomes. It was reported that procedural success was 92% for both 21F (n=63) and 18F (n=112) devices, with failures due mostly to misplacement (3% for 21F and 5% for 18F). Laborde said that the higher rate of misplacement for the 18F device came as a surprise, and that the 18F is more flexible than the 21F. Study design In regard to age, sex, and clinical profiles, Laborde said that there were no significant differences between patients in the 21F versus the 18F groups. The study criteria included native aortic valve disease, AV annulus between 20mm and 27mm, and sino-tubular junction ≤43mm. Endpoints were procedural success, 30-day success, and long-term outcome. Complications For the initial 30 days post-procedure, complications appeared to be minimal for both devices. The majority of complications were vascular complications, stroke/TIA, and pacemaker implantation. Results for 30- day mortality and logistic EuroSCORE were similar for both devices (26%, 21F; and 24%, 18F). Total day mortality for the 21F device was 14% compared with15% for the 18F device, said Laborde. The mean blood-flow-gradient measurements were also similar for both devices. The mean gradient for the 21F device decreased from 41.92mmHg pre-procedure to 11.55mmHg at discharge, while the mean gradient for the 18F device also significantly decreased (from 47.21mmHg to 5.07mmHg at discharge). Laborde reported that results were pooled for both devices for a follow-up time of 320 days. He added that currently, there is a 70% cumulative survival in 337 patients treated worldwide with the CoreValve Percutaneous Aortic Valve Replacement System. Mitral – EVEREST II Also presented at TCT were the data from the EVEREST II study a 107- person, non-randomised patient registry. The presentations evaluated the reduction of mitral regurgitation severity with the MitraClip device and the positive impact of this reduction for patients. The ongoing randomised study arm of EVEREST II is evaluating the safety and efficacy of the MitraClip device compared to surgical mitral valve repair or replacement for the treatment of mitral regurgitation. Highlights of the data presented this week include 82% of patients who had a successful result with the MitraClip device remain free from surgery 36 months after the procedure. Also 74% of patients with one or more Clips implanted experienced a reduction to less than or equal to Grade 2+ MR as assessed by the EVEREST Core Laboratory and graded per the American Society of Echocardiography guidelines. Twelve months after a successful MitraClip procedure, significant reverse remodelling of the left ventricle was demonstrated. Reverse remodelling was assessed based on five echocardiographic measures, including left ventricular end-systolic dimension. In line with the reverse remodelling, 94% of patients who had a successful result with the MitraClip device had improved or stable New York Heart Association (NYHA) Class at 12 months following the procedure. “Our work to reduce mitral regurgitation with a percutaneous approach continues to produce compelling results,” said Dr Ted Feldman, who presented the 36 month follow-up data and EVEREST II national co-principal investigator and Director of the Cardiac Catheterization Lab at Evanston Northwestern Healthcare in Evanston, IL. “The reduction in MR severity achieved, along with the stability of the results at 36 months and the preservation of subsequent surgical options, leads us to believe that the MitraClip device is likely to become a viable first-line option for treating MR in many patients.” Dr Michael Rinaldi, Director of Clinical Research, Sanger Clinic/Carolinas Medical Center, who presented the reverse remodelling data commented: “The reverse remodelling data is important in that it provides compelling, objective evidence that the MitraClip device is having a positive impact on patients. Additionally, patients with the MitraClip report that they feel better and are able to engage more fully in activities they enjoy.” The EVEREST study continues at more than 35 centres in North America, with more than 300 patients enrolled and more than 300 MitraClip devices implanted to date. Investigators are currently enrolling patients in both arms of the EVEREST II study, a randomised, controlled arm and a high risk registry arm with the goal of completing enrolment by the end of 2008. “This study is gathering valuable information that cardiac surgeons and interventional cardiologists have never had before. The data provides new insights about treatment considerations for patients with significant degenerative or functional mitral regurgitation,” said Feldman. “We encourage physicians to refer such patients to EVEREST investigators.”
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