In the 3.6% of patients undergoing the valve-in-valve procedure to fix a leak, the most common type of device malposition was deployment that was too low inside the left ventricular outflow tract (75% of cases). The only statistically significant baseline difference between the patients needing a second valve and those who did not is that the former group had a slightly larger average annulus diameter (23.6 mm vs 22.1, p=0.010).

In most cases, balloon dilation was necessary to optimize the expansion of the second device, but this did not damage the leaflets or aortic root structures. There were no major adverse cerebrovascular and cardiac events within 30 days for the patients undergoing the a second safety valve implant, and the procedural, 30-day, and 12-month outcomes of the valve-in-valve group, including survival and major adverse events, were statistically equivalent to the outcomes of those who did not require a second intervention (95.5% for the valve-in-valve patients and 86.3% for the patients who did not need a second procedure). Procedural success was obtained in 100% of the valve-in-valve patients, with no periprocedural death. There were no cases of valve deterioration or new onset of central or perivalvular regurgitation observed or any reports of thrombotic or embolic events in the valve-in-valve group, "which reflects well on the design features and the endothelialization of the [CoreValve] device," according to the authors.

"The valve-in-valve technique can be used readily in the catheterization laboratory as bailout therapy for a failed implantation resulting from a malpositioned valve with severe paraprosthetic leak when the attempt of reposition with the snare technique fails, preventing conversion to emergency open-heart surgery," the authors explain. "The availability of a bailout provides a margin of safety and enhances operator confidence. This is important for a nascent technology like TAVI to gain widespread clinical acceptance." This margin of safety is important because which patients will develop a leak is difficult to predict prior to their initial valve-replacement procedure, Ussia told heartwire.