Mechanical versus Bioprosthetic Aortic Valve Replacement in Middle-Aged Adults: A Systematic Review and Meta-Analysis

Abstract

Background: Mechanical prostheses and bioprosthetic prostheses have their own advantages and disadvantages. Mechanical ones are recommended for younger patients (<50 years old), and bioprosthetic ones are recommended for older patients (>70 years old). There is still debate regarding which kind of prosthesis is better for middle-aged patients (50 to 70 years old) receiving aortic valve replacement (AVR). To solve this problem, we conducted this meta-analysis. Given that only one randomized controlled trial (RCT) study was included, we conducted a subgroup analysis of RCT and propensity score matching (PSM) retrospective studies to reduce the bias. Methods: We systematically searched articles related to clinical outcomes of mechanical and bioprosthetic prostheses in middle-aged patients receiving AVR in the PubMed, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases. The published date was up to 1 October 2022. Studies were excluded if not only middle-aged patients were included, or if they lacked direct comparisons between mechanical and bioprosthetic prostheses. Results: In total, 22 studies with 32,298 patients were included in the final analysis. The results show that patients aged between 50 and 70 receiving AVR with mechanical prostheses achieved better long-term survival and fewer reoperations and valve-related events but suffered more with bleeding events. No significant difference could be found in terms of early mortality and long-term cardiac death. The same results could be observed in the subgroup analysis of RCT and PSM retrospective studies. Conclusion: Both mechanical and bioprosthetic prostheses are beneficial to middle-aged patients undertaking AVR procedures. However, mechanical prostheses show better clinical outcomes in long-term survival and comorbidities. Individual recommendation is still necessary.

Mechanical versus Bioprosthetic Aortic Valve Replacement in Patients Aged 50 to 70 Years

“…Among numerous studies comparing the clinical outcomes of mechanical and bioprosthetic AVR in middle- aged patients, some studies found that long-term survival was significantly greater with mechanical AVR than bioprosthetic AVR [ 3 , 8 , 10 - 17 ], whereas others found no significant survival difference [ 18 - 21 ]. The most recent meta-analysis, which included 22 publications and involved 32,298 patients, reported greater long-term survival with mechanical AVR than bioprosthetic AVR among individuals aged 50 to 70 years [ 13 ]. However, they also reported that when they reduced the upper limit of the age range to 65 years, the survival benefit of the mechanical valve disappeared.…”

“…3A ). Among the comparative studies analyzing valve types in middle-aged AVR, only a few reported a significant difference in the occurrence of stroke [ 12 , 13 , 15 , 18 , 20 , 24 , 28 - 30 ]. Stroke is a devastating complication that may occur early or late after prosthetic valve replacement and results from embolism, intracranial hemorrhage, or both [ 31 ].…”

Immediate and Medium-Term Results of Aortic Valve Replacement With Biological Prosthesis in Elderly Patients: One Center’s Experience

“…The surgical repair of the aortic valve is a significant heart procedure that ranks second in cardiac surgery and among the top heart treatments. Depending on the patient's features, a biological, mechanical, or autopericardium replacement may be chosen [16]. Depending on the surgeon's discretion, there are various implantation procedures for aortic valve repair, including U-shaped sutures on spacers, an interrupted sew technique for thin aortic valve rings, and continuous sutures [17].…”