New research released this week provides more support for the use of transcatheter aortic valve-in-valve (VIV) implantation as a means of replacing previously implanted valves that have deteriorated over time.
The study is important validation for VIV surgery, which may be the best or only option for patients who have bioprosthetic heart valves that are failing. Surgeons are increasingly opting for bioprosthetic valves, but the biological-tissue implants aren’t as durable as their mechanical counterparts, suggesting that revision surgeries are poised to surge.
Heart failure patients, including those with deteriorating bioprosthetic valves, are generally treated with open heart surgery, but some patients are too old or too sick for the procedure. Transcatheter VIV surgery has gotten a lot of attention as a potential alternative, and results from the 1st-of-its-kind study published this week may encourage more physicians to consider the procedure.
The study also provides some insight into which patients may be the best candidates for VIV treatment. Overall survival following VIV surgery was reported as 83.9%, but patients with stenosis fared worse at 1 year (76.6% survival) than those with aortic regurgitation (91.2% survival).
"Thorough assessment of candidates for valve-in-valve implantation is a key step to obtain optimal results," the authors wrote. "The current analysis highlights the need for meticulous evaluation of bioprosthesis mechanism of failure before attempting a valve-in-valve procedure."
Patients with larger valves also had a higher rate of survival than those with smaller valves, which may have implications for the way in which surgeons implant the original bioprosthetic valve.
"According to the VIVID Registry analysis, valve-in-valve outcomes are worse in patients with small surgical valves (label size ≤21 mm) and those with stenosis as the mechanism of failure; an attempt to address these limitations may possibly be made during the index procedure by providing the largest effective orifice area achievable," according to the study. "However, annular enlargement and other related techniques must balance the potential benefit of larger valve against described increase in operative complications."
Published this week in the Journal of the American Medical Assn., the study includes nearly 460 patients with failing bioprosthetic valves who underwent VIV procedures from 2007 to May 2013, including 55 centers around the world. The collected registry data was comprised mainly of patients treated with Medtronic’s (NYSE:MDT) CoreValve and Edwards Lifesciences’ (NYSE:EW) Sapien implants.
Neither Edwards nor Medtronic has FDA approval to market implants for VIV procedures, but physicians are free to use the device "off-label" at their discretion. Both Sapien and CoreValve are approved for VIV use in the European Union.