For patients with severe aortic stenosis, offering either the Edwards Lifesciences Sapian or Medtronic CoreValve prosthetic valves allows a greater number of patients to be suitable for transcatheter aortic valve implantation (TAVI), according to a study published in the August edition of the Journal of the American College of Cardiology: Cardiovascular Interventions.
“TAVI has achieved great success in treating high-risk and inoperable patients with severe aortic stenosis,” the authors wrote. “However, anatomical constraints remain, in particular with peripheral arterial access for transfemoral approaches and aortic valve annular dimensions for all approaches.”
To evaluate the proportion of patients anatomically suitable for treatment by multiple TAVI approaches, Hasan Jilaihawi, BSc, MBChB, of the Montreal Heart Institute in Canada, and colleagues assessed 100 patients at two centers who were at a high or prohibitive risk of conventional surgery.
The researchers used McNemar paired nominal tests to compare patients suitable for a two-device TAVI approach to those suitable for single-device approaches.
Researchers performed a transthoracic or transesophageal echocardiography and invasive angiography in order to assess anatomical suitability. The mean age of patients was 80.9 years.
According to the researchers, transfemoral access requirements for the Sapien include a minimal iliofemoral dimension of at least 7 mm for the 22 F/22 mm device and at least 8 mm for the 24 F/26 mm device.
The 18 F CoreValve device requires a minimal iliofemoral dimension of at least 6 mm.
The researchers also assessed the suitability of the patients for the Edwards XT Novaflex delivery system.
Results showed that the suitability was 28 percent for the Sapian transfemoral devices, 88 percent for the Sapien transapical device and 78 percent for the XT Novaflex transfemoral device.
CoreValve suitability was 84 percent for transfemoral and 89 percent using transaxillary and direct aortic approaches.
When the upper limit of annular suitability was increased from 24 to 25 mm, suitability increased by 8 percent—20 percent to 28 percent. Suitbility increased from 74 percent to 88 percent with use of the transapical approach.
Twelve patients were unsuitable for the Edwards device procedures, but eight of these 12 patients were suitable for the Medtronic CoreValve. Eleven patients were not suitable for the CoreValve device, but of those 11, eight were suitable for the Edwards device. Three percent of patients were anatomically unsuitable for all approaches.
The two-device strategy increased patient’s suitability for TAVI by 9 percent, from 88 percent to 97 percent for Edwards-based approaches, and by 8 percent for Medtronic approaches, 89 percent to 97 percent.
Researchers noted, "With the combination of transfemoral devices available, the additional contribution of alternative access approaches (transapical for the Edwards Sapien system and transaxillary/direct aortic access for the Medtronic CoreValve system) is limited. We observed that 92 percent of cases were suitable for a multidevice transfemoral approach and only 5 percent more cases were afforded treatment by the addition of other approaches. This supports the rationale that TAVI should primarily be a catheterization laboratory-based transfemoral procedure, reserving other approaches for a minority. This is not presently the case for the Edwards Sapien system, which has a greater reliance on the transapical approach; the imminent reduction in device profile via the Novaflex system is likely to dramatically change practice."
According to the researchers, 52 of the 100 patients have currently undergone TAVI—two cases failed, post-procedural stroke occurred in one patient and four deaths were recorded.
“This study of consecutive patients referred for TAVI demonstrates that with a two-device strategy, more patients are anatomically suitable for this therapy,” the authors wrote. “The use of both devices [Medtronic and Edwards] is complementary and makes TAVI available for patients at either end of anatomical requirements.”
While the authors said that creating new devices will lead to greater anatomic suitability, qualitative differences between the devices will remain and a tailored therapy will become more relevant down the road as more physicians are trained to implant multiple devices.
“Undoubtedly, these novel devices will further increase the range of patients anatomically