Long-term results of the Mitroflow aortic pericardial bioprosthesis in over 800 patients: limited durability and mechanisms of dysfunction.

OBJECTIVES: The Mitroflow aortic pericardial bioprosthesis was widely employed in the past. However, some authors have recently reported early structural valve deterioration (SVD) of the Mitroflow LA/LXA model. Thus, we reviewed our experience with the Mitroflow bioprosthesis and studied the risk factors for SVD and mortality. METHODS: Records of patients who underwent aortic valve replacement with a Mitroflow bioprosthesis between November 2005 and January 2015 were retrospectively evaluated with Kaplan-Meier, Cox-regression and multistate analysis. Only patients with a complete clinical follow-up were included in the study. Average follow-up was 45 months and ended on 1 April 2016. RESULTS: Between November 2005 and January 2015, among the 916 patients undergoing aortic valve replacement with the Mitroflow prosthesis at our Institution, the 832 (90.8%) patients with follow-up information were included into the study. Fifty-two (6.2%) patients developed SVD (stenosis, n = 38; regurgitation, n = 7; mixed, n = 7). Freedom from SVD was 95.4% and 67.9%, at 5 and 9 years, respectively, without differences after stratification according to the prosthesis model ( P = 0.87) and prosthesis size ( P = 0.70). At the multivariable analysis, increasing age was identified as a protective factor against SVD (hazard ratio = 0.94, P < 0.001). Twenty (38.4%) patients with SVD underwent redo aortic valve replacement. At 5 and 9 years, survival was 64.5% and 43.1%, repectively. According to the multistate analysis, the fraction of patients living with degenerated valves at 9 years was 10.0%; 7.1% died following degeneration. CONCLUSIONS: The LA/LXA Mitroflow model showed limited long-term durability. Degenerated prostheses showed more stenosis than regurgitation. Patient age played an important role in the development of SVD.

Impact of sinuses of Valsalva on prosthesis durability in patients undergoing ascending aorta and aortic valve replacement with Carpentier-Edwards bioprosthesis: a propensity score-based study.

OBJECTIVES: The effect of sinuses of Valsalva on aortic bioprosthesis durability has not been investigated so far. The aim of this study was to compare durability of the Carpentier-Edwards aortic bioprosthesis in patients undergoing aortic valve and ascending aorta replacement as a composite bioconduit (Group A, case group) versus patients undergoing separate replacement of the aortic valve and ascending aorta, with preservation of the aortic root (Group B, control group), between January 2000 and January 2014. METHODS: Records of Group A (n = 133) and Group B (n = 162) patients were retrospectively reviewed. End-points were evaluated among groups in three ways: before and after propensity score 1:1 matching (Group A, n = 94; Group B, n = 94 patients) and after patient stratification through quintiles of propensity scores. RESULTS: There was no difference among groups regarding mean and maximal trans-prosthetic pressure gradients at discharge (P = 0.07 and 0.45, respectively). Maximal trans-prosthetic gradients were lower in Group A patients at last control (P = 0.03). Structural valve deterioration (SVD) was due to prosthesis regurgitation (Group A, n = 5; Group B, n = 1), stenosis (Group A, n = 2; Group B, n = 5) or combined (Group A, n = 4; Group B, n = 2). After a mean follow-up of 68 ± 42 months, there was no difference among groups, at 5 and 12 years, regarding mortality, freedom from SVD, from redo aortic valve replacement for SVD and cardiac redo of any type, before and after matching and after stratification according to quintiles of propensity scores. CONCLUSIONS: Within the 12-year follow-up, the absence of the sinuses of Valsalva seems to have no influence on durability of Carpentier Edwards aortic bioprosthesis. Longer follow-up may be warranted.

Comparison between biological and mechanical aortic valve prostheses in middle-aged patients matched through propensity score analysis: long-term results.

OBJECTIVES: Choice of prosthesis type in middle-aged patients undergoing aortic valve replacement (AVR) is still debated. The aim of this study is to compare long-term follow-up results in middle-aged patients who underwent isolated AVR with a biological or mechanical prosthesis. METHODS: A retrospective analysis of a single-centre database was performed to identify patients aged between 55 and 65 years old who underwent isolated AVR with a biological or mechanical prosthesis from January 1996 to January 2008. Sixty patients with a biological aortic valve prosthesis (Group A) were identified and matched through propensity score analysis to other 60 patients with a mechanical aortic valve prosthesis (Group B). RESULTS: There was no difference among groups regarding postoperative complications. Follow-up amounted to 117 ± 51 months. In Group A and B patients, 10- and 15-year survival was 77 ± 6 vs 75 ± 6 and 54 ± 13 vs 53 ± 8%, respectively (P = 0.95); 10- and 15-year freedom from structural valve deterioration, 81 ± 7 vs 100 and 64 ± 12 vs 93 ± 5%, respectively (P = 0.003); 10- and 15-year freedom from redo AVR, 87 ± 6 vs 91 ± 5 and 73 ± 11 vs 91 ± 5%, respectively (P = 0.04); 10- and 15-year freedom from endocarditis, 94 ± 3 vs 98 ± 2 and 83 ± 8 vs 98 ± 2%, respectively (P = 0.05); 10- and 15-year freedom from bleeding events, 98 ± 2 vs 96 ± 5 and 88 ± 6 vs 77 ± 10%, respectively (P = 0.98); and 10- and 15-year freedom from cerebrovascular events, 94 ± 3 vs 97 ± 3 and 83 ± 8 vs 97 ± 3%, respectively (P = 0.03). CONCLUSIONS: While survival was not different among groups, patients with a biological prosthesis showed a higher valve-related morbidity at follow-up. Therefore, middle-aged patients should preferably receive a mechanical prosthesis.