LAUSR

February 12, 2019 983 Aortic valve replacement (AVR) choices for young patients involve particular complexities because of variable anatomy, ongoing somatic growth, active lifestyles, valve durability, available prosthesis size, and limited data on valve safety and durability.1 Bioprosthetic valves are attractive in young populations because they often do not require anticoagulation. However, limited data in children and young adults exist on the expected performance and mechanisms of failure of new-generation bovine pericardial tissue valves for AVR.2–4 We previously reported a catastrophic valve failure secondary to severe leaflet calcification in an asymptomatic 13-year-old girl 2 years after AVR with a Mitroflow LXA (M-LXA) valve. An urgent single-institution safety study was conducted reviewing serial echocardiograms on all patients with implanted bovine pericardial tissue aortic valves, including the Magna/Magna Ease (M/ME) and M-LXA valves. With a median follow-up of 13.7 months, early valve failure was found in 4 of 14 other patients receiving M-LXA valves attributable to leaflet calcification and stenosis prompting valve rereplacement.5 This communication provides an extended assessment on durability and performance of the M/ME and M-LXA aortic valve bioprostheses in patients <30 years at implantation. Our institutional review board approved this study; consent was not obtained because this was part of a safety review. From November 2002 to 2017, we performed AVR in 247 patients <30 years of age: mechanical valve (90, 36%), autograft/Ross procedure (84, 34%), and bioprosthetic valve (73, 30%). Valve choice was based on anatomic and patient preference considerations. Among patients who underwent bioprosthetic AVR, 58 (79%) received M/ME valves at a median age of 18.8 years (range, 3.8–29.2), and 15 (21%) received M-LXA valves at a median age of 13.0 years (range, 7.6–24.9). Median follow-up (time to explant, death, or last echocardiogram for valves in situ) was 2.8 years (range, 0.0–13.8, M/ME) and 2.7 years (range, 1.5–8.4, M-LXA). Freedom from valve failure (explant or death) among patients with M/ME valves was 100% at 2 years, 96.4% at 3 years, and 87.6% at 4 years, in comparison with 100% at 1 year, 73.3% at 2 years, 40% at 3 years, and 20% at 4 years among patients with M-LXA valves (P<0.001, log-rank test, Figure). Reasons for explant of M/ME valves were endocarditis (n=1) and increasing left ventricular outflow/valve gradient (n=5). Among the latter, structural valve degeneration with leaflet thickening and immobility led to explant in 2 patients (15.6 and 28.2 years of age at implant, valve duration 6.1 and 13.8 years, respectively). Obstruction from pannus ingrowth with well-functioning and mildly calcified leaflets occurred in 2 other patients (7.1 and 15.6 years at implant, valve duration 3.8 and 2.9 years, respectively). Subaortic obstruction with pliable leaflets was present in 1 patient (25 years at implant, valve duration 7.4 years). An accelerated rate of gradient rise was seen during the last year before explant in 4 patients (2 with pannus, 1 with structural valve degeneration, and 1 with subaortic obstruction, Figure). Susan F. Saleeb, MD Kimberlee Gauvreau, ScD John E. Mayer, MD Jane W. Newburger, MD, MPH