A pioneering in vitro study reveals how contemporary mechanical heart valves respond to intentional fracturing with commercially available angioplasty balloons. Findings from the investigation, which appears in the February 23 edition of JACC: Cardiovascular Interventions, offered additional insight for high-risk patients with valve dysfunction who may not be candidates for redo surgery. “We demonstrate that leaflet fracturing is feasible at relatively low pressures (1-6 bar) with commonly available and established balloons, directly informing potential bailout strategies for high-risk patients,” wrote the paper’s authors, led by Paulina Anna Jankowska, MD, of the University Hospital Heart Center Brandenburg, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany. “Among dilatation catheters, the Atlas Gold PTA catheter performed particularly well because of its shape and high-pressure tolerance.” Study methodology Investigators conducted a standardized bench study of 17 bileaflet mechanical valves assessing catheter crossability, fracture thresholds, fragment behavior and ring integrity. The investigation revealed that leaflet fracture occurred at pressures between 1 and 6 bar, with 58% of valves fracturing at ≤4 bar, which was within the rated burst pressure of all tested balloons. Average fracture pressure was lower in mitral valves (2.5 ± 0.7 bar) than in aortic valves (3.78 ± 1.1 bar), although this likely reflected differences in valve size rather than design. The leaflet–ring junction consistently emerged as the structural weak point. “Given the absence of visible differences in prosthesis structure or leaflet thickness (0.5-0.7 mm) between mitral and aortic valves, we suggest that valve diameter, rather than valve type, plays a significant role in determining the pressure required for fracture when using the same size angioplasty balloon,” the authors wrote. Kinetic risk Fragments travelled at 0.01 to 0.02 m/s before rapidly losing momentum. Larger mitral prostheses (29–33 mm) were more likely to yield intact leaflet removal, while smaller aortic models frequently produced sharper fragments. Importantly, valve rings demonstrated far greater resistance. No structural damage occurred at pressures up to 8 bar, and even at 10–25 bar only minor cracks appeared in the carbon coating, leaving the internal metal core intact. “In the short term, however, the clinical application of fracturing and reimplanting a new biological valve will remain a bailout strategy reserved for carefully selected cases,” the authors concluded. “Nevertheless, these findings suggest that a new therapeutic avenue may be opening up, warranting further clinical investigation.” Durable prostheses John G. Webb, MD, from St. Paul’s Hospital, University of British Columbia in Vancouver, and Stephanie L. Sellers, PhD, from Providence Research & Centre for Heart Lung Innovation at the University of British Columbia, said that mechanical prostheses were durable but could fail. In accompanying editorial commentary, they added that traditionally, redo surgery had been required, as rigid pyrolytic carbon leaflets were thought unsuitable for transcatheter valve-in-valve approaches. “They demonstrate in vitro that the pyrolytic carbon leaflets of bileaflet mechanical valves can be easily broken using routine commercially available valvuloplasty balloons at modest pressures,” the experts concluded. Sources: Jankowska PA, Butter C, Kühnel RU. Serial In Vitro Investigation of the Fracture Properties of Mechanical Heart Valves. JACC Cardiovasc Interv. 2026;19:505–513. Webb JG, Sellers SL. Transcatheter Valve Implantation in Failed Mechanical Valves? JACC Cardiovasc Interv. 2026;19(4):514–516. Image Credit: paul – stock.adobe.com