Related Experiment Video
Updated: Jan 28, 2026

Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy
Published on: September 11, 2014
Bioprosthetic valve fracture: Technical insights from a multicenter study
Keith B Allen1, Adnan K Chhatriwalla2, John T Saxon2
1Department of Cardiothoracic Surgery, Saint Luke's Mid America Heart Institute and University of Missouri-Kansas City School of Medicine, Kansas City, Mo.
Objective:
Valve-in-valve transcatheter aortic valve replacement (VIV TAVR) can result in high residual gradients that are associated with increased mortality. Bioprosthetic valve fracture (BVF) has been shown to improve residual gradients following VIV TAVR; however, factors influencing the results of BVF have not been studied.
Methods:
BVF was performed in 75 patients at 21 centers. Hierarchical multiple linear regression was performed to identify variables that were associated with lower final transvalvular gradient.
Results:
Surgical valves with a median true internal diameter of 18.5 mm (interquartile range, 17.0-20.5 mm) were treated with VIV TAVR in conjunction with BVF using balloon-expandable (n = 43) or self-expanding (n = 32) transcatheter heart valves with a median size of 23 mm (interquartile range, 23-23 mm). There were no aortic root disruptions, coronary occlusions, or new pacemakers; in-hospital or 30-day mortality was 2.6% (2 out of 75). Final mean transvalvular gradient was 9.2 ± 6.3 mm Hg, but was significantly lower when BVF was performed after VIV TAVR compared with BVF first (8.1 ± 4.8 mm Hg vs 16.9 ± 10.1 mm Hg; P < .001). After adjusting for timing of BVF (ie, before or after VIV TAVR), transcatheter heart valve size/type, surgical valve mode of failure, true internal diameter, and baseline gradient and BVF balloon size, performing BVF after VIV TAVR (P < .001) and using a larger BVF balloon (P = .038) were the only independent predictors of lower final mean gradient.
Conclusions:
BVF can be performed safely and results in reduced residual transvalvular gradients. Performing BVF after VIV TAVR and using larger balloon appears to achieve the best hemodynamic results.
Related Concept Videos
Heart Valves
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...
Fractures: Bone Repair
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the...
Mitral Valve Prolapse I: Introduction
Mitral Valve Prolapse II: Assessment and Management
Mitral Valve Prolapse III: Nursing Management
Case Studies

