Accelerated Degeneration of a Bovine Pericardial Bioprosthetic Aortic Valve in Children and Young Adults
What are the early failure rates for bovine pericardial aortic bioprosthetic valves in children and young adults?
A retrospective review was performed at a single center. The death of a child with accelerated bioprosthetic aortic stenosis prompted enhanced surveillance of all children with bovine pericardial aortic bioprosthetic valves at the study institution.
During the study period, 27 patients <30 years of age underwent aortic valve replacement (AVR) with a bovine pericardial prosthesis, of which 15 underwent AVR with the Mitroflow LXA valve, and 12 underwent AVR with Magna/Magna Ease valves. For patients undergoing AVR with the Mitroflow LXA valve, freedom from valve failure was 100% at 1 year, 53% (95% confidence interval [CI], 12-82) at 2 years, and 18% (95% CI, 1-53) at 3 years. There were no failures of the Magna/Magna Ease valves as of 3 years post-implantation. Patients with Mitroflow LXA valves tended to be smaller (median body surface area 1.42 vs. 1.93 m2; p = 0.002) and younger (median age 13.0 vs. 20.9 years; p = 0.02) as compared with patients with Magna/Magna Ease valves. The mechanism of valve failure appeared to be intrinsic leaflet calcification.
Young patients undergoing AVR with Mitroflow LXA bioprosthetic valves are at high risk for rapid progression to severe aortic stenosis. Patients with these valves should undergo increased echocardiographic surveillance. The data suggest the Mitroflow LXA valve should not be used in the aortic position in patients <30 years of age.
This report describes early failure of the Mitroflow LXA bioprosthetic valve in young patients (<30 years) undergoing AVR. Choice of valve is always difficult in this age group, in large part due to the need for anticoagulation with prosthetic valves and the need for re-intervention and potential for autograft failure with the Ross procedure. Importantly, this report demonstrates differences between different types of bioprosthetic valves, with the Mitroflow LXA valve performing poorly and the Magna/Magna Ease valve performing relatively well, at least for the short- to mid-term. This may be due to a propriety treatment used on the Magna and Magna Ease valves to prevent mineralization. Most concerning in this report is the rapid deterioration of function of the Mitroflow valves, with progression from minimal gradients to life-threatening aortic stenosis over a median of 6 months.
Keywords: Heart Valve Prosthesis, Body Surface Area, Autografts, Aortic Valve Stenosis
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