Structural abnormalities after aortic root replacement with stentless xenograft

ABSTRACT Objective In complex and high-risk aortic root disease, the porcine Freestyle Stentless bioprosthesis ® (Medtronic Incorporated, Minneapolis, Minnesota, US) is an important surgical treatment option. We aimed to determine prevalence and clinical impact of structural and functional abnormalities after full-root Freestyle implantation. Methods Our cross-sectional two-centre study combined with clinical follow-up included 253 patients with full-root Freestyles implanted from 1999 to 2017. Patients underwent transthoracic echocardiography (TTE) and contrast-enhanced, ECG-gated 4-dimensional cardiac computed tomography (4DCT) at median age 70, IQR 62-75, years. After 4DCT, clinical follow-up continued throughout 2018. Median follow-up was 3.3 years prior to 4DCT and 1.4 years after. Results We identified abnormalities in 46% of patients, including pseudoaneurysms (n=32, 13%), moderate or severe coronary ostial stenosis (n=54, 21%), and moderate-severe leaflet thickening or reduced leaflet motion (n=51, 20%). TTE only identified one patient with pseudoaneurysm. After 4DCT, the unadjusted hazard ratio for surgical reintervention among patients with abnormal 4DCT was 4.2 (95%CI 1.2-15.3), in all 10% required a reintervention. 4DCT abnormalities were associated with a statistically non-significant increased risk of death, stroke or myocardial infarction (HR 2.4, 95%CI 0.7-7.6). In all, 4.0% died, 3.6% had a myocardial infarction, 2.0% a stroke. Conclusion Structural and functional abnormalities of the aortic root are frequent after Freestyle implantation and TTE appears insufficient for follow-up. Abnormalities may be associated with increased risk of reintervention and potentially adverse clinical outcomes. Longer follow-up and larger study populations are needed to further clarify the clinical implications of abnormalities identified with 4DCT.