Clinicians at the University of Michigan Frankel Cardiovascular Center say their refined processes have optimized aortic stenosis treatment, shortened the time between referral and surgery, and led to excellent outcomes.
According to G. Michael Deeb, MD, who is Herbert Sloan Collegiate Professor of Cardiac Surgery and Director of the Multidisciplinary Aortic Clinic at the Frankel Cardiovascular Center, aortic stenosis patients are treated by a team of cardiovascular surgeons, cardiologists and a host of other subspecialists who collaboratively choose the most appropriate treatment, whether it be open surgery or transcatheter aortic valve replacement (TAVR).
“The Centers for Medicare & Medicaid Services have guidelines that specify these surgeries should be joint efforts by interventional cardiologists and cardiac surgeons, but we’ve taken that model several steps further,” said Dr. Deeb.
A Team Approach
Each Tuesday, subspecialists at the Frankel Cardiovascular Center meet and review upcoming valve replacement patients. They discuss topics ranging from the physiology of aortic stenosis to the ethics of performing a particular procedure in a patient, and then determine the most suitable treatment for a given patient.
“The team includes three interventional cardiologists; four cardiac surgeons; imaging physicians who help us decide which size valve to use and where to position it; and research coordinators,” Dr. Deeb explained. “We decide whether patients qualify for TAVR, open surgery, if they are a good fit for one of our clinical trials or if they are too sick to undergo a procedure at all.”
According to Stanley J. Chetcuti, MD, who is Eric J. Topol Collegiate Professor of Cardiovascular Medicine and Associate Professor of Internal Medicine at the university, the devices used for TAVR are “constantly evolving, and we have access to the most sophisticated and effective valves.”
The two most frequently used commercial valves at the University of Michigan are Medtronic’s Evolut R and Edwards Lifesciences’ SAPIEN 3, both of which reduce the risk for valvular leakage, Dr. Chetcuti said. The Evolut R is repositionable, allowing clinicians to place the valve, release it up to 90%, determine if there is a leak and then either fully release the valve or reposition it in another location if necessary.
“If we need to, we repeat this process until we find a good position,” said Dr. Chetcuti.
The SAPIEN 3, on the other hand, reduces the risk for leakage by placing a skirt around the valve to tightly seal the edges, Dr. Chetcuti explained.
Ongoing Clinical Trials
Dr. Chetcuti added that the team is also participating in several studies, most of which involve randomization of patients to open surgery or a TAVR device.
“Right now, we’re completing two trials for patients at moderate risk of mortality with surgery,” said Dr. Chetcuti. “We’re also excited to be studying Boston Scientific’s Lotus Valve, which is a self-adjusting, repositionable and retrievable valve. Further, we anticipate an upcoming study with a larger-diameter version of the Evolut R, which would allow us to treat an additional 10% of patients with aortic stenosis who would otherwise have anatomy too large to qualify for TAVR.”
The university closely tracks patient outcomes, logging clinical, demographic, procedural and follow-up information from each procedure into separate national and state registries.
“Our outcomes from 2014 were very encouraging,” noted Dr. Chetcuti, who anticipated the team will have conducted more than 600 TAVR procedures by the end of 2015. “In fact, our outcomes with the Medtronic CoreValve and the Edwards SAPIEN 3 were better than the data from other pivotal studies. Our model is clearly working in our patients’ favor.”
TRANSCATHETER VALVE-IN-VALVE IMPLANTATION:
NEW OPTION FOR BIOPROSTHETIC VALVE FAILURE
Recently, an important option for heart valve implantation has been approved, and is already available at the University of Michigan (U-M) Frankel Cardiovascular Center.
The SAPIEN XT (Edwards Lifesciences) transcatheter heart valve allows for minimally invasive aortic valve-in-valve procedures, which offers an important option for the patient whose previously implanted but compromised prosthetic valve needs to be replaced, but who wishes to avoid open surgery.
There is a large population of patients whose prosthetic valves await replacement. Many patients with congenital heart diseases whose bicuspid valves were replaced with prosthetic valves will require numerous procedures through the years as their implanted valves become compromised. These repeated cardiac surgeries are associated with significant morbidity and mortality.
In the valve-in-valve procedure, the new valve is tightly placed within the failing bioprosthetic valve. Although the procedure has been approved, it had been performed selectively at U-M several times; thus, expertise in this complex approach is already available.
The PARTNER II (Placement of AoRTic TraNscathetER Valves) trial found an overall one-year survival rate of 86.6% and a stroke rate of 3.7% in a 197-patient, multicenter study of this high-risk population. Survival at 30 days was 100%.
High-risk and inoperable patients underwent TAVR and received the Edwards Sapien 3 aortic valve. Most patients were more than 80 years old and underwent transfemoral TAVR.
One-year survival rate: 85.6%
Disabling stroke rate after one year: 2.4%*
Patients with severe paravalvular leak: 0
* Although 2.7% had moderate paravalvular leak, this type of leak was not associated with increased risks for death, clinical valve thrombosis or structural valve deterioration.
Another study of 60 patients who underwent TAVR and received the Evolut R valve showed similar survival rates at one year. Patients in this multicenter international study were considered to be at high or extreme risk for mortality with surgery.
6-month survival rate: 95%
One-year survival rate: 93.3%
One-year stroke rate: 3.4%