Durability of porcine bioroots in younger patients with aortic root pathology: A propensity-matched comparison with composite mechanical roots

Background: We present a comparison of porcine bioroot and composite mechanical root replacement in a large series of patients younger than 60 years who required full root replacement for true root pathology. Methods: Between 1997 and 2007, we performed 986 aortic root replacement procedures, including 391 porcine bioroots and 515 composite mechanical roots for true root indications. Of these, 504 patients were younger than 60 years old at time of the operation. Porcine bioroots were placed in 138 patients, including 38 St. Jude Toronto Root (St. Jude Inc, St. Paul, MN), 98 Medtronic Freestyle (Medtronic Inc, Minneapolis, MN), and 2 Edwards Prima (Edwards Lifesciences Inc, Irvine, CA). Standard univariate, logistic regression, Cox regression, and propensity matching techniques were used. Results: To adjust for baseline differences in risk factor profiles, propensity matching yielded a final matched data set of 128 matched pairs, with no differences in preoperative risk factor profile or indication for operation. Overall 30-day operative mortality was 2.3% for porcine bioroot patients vs 1.6% for mechanical root patients (p = 0.6). Root type did not influence early (odds ratio, 0.8; 96% confidence interval, 0.2 to 3.2) or late mortality (hazard risk, 1.4; 95% confidence interval, 0 0.5 to 3.8). Multivariate predictors of late mortality included (hazard ratio, 95% confidence interval) age in years (1.01; 1.01 to 1.03), chronic renal failure (3.6; 1.1 to 12.6), and preoperative bacterial endocarditis (3.6; 1.1 to 11.8). Freedom from reoperation was similar between groups; however, bleeding events were more common among mechanical root patients. Conclusions: Porcine bioroots provide durable midterm to late-term outcomes after aortic root replacement for true root indications and are an appealing alternative in younger patients because they limit morbidity associated with anticoagulant-related bleeding.