Background: Mechanical prostheses and bioprosthetic prostheses have their own advantages and disadvantages. Mechanical ones are recommended for younger 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.

This review synthesizes the immunometabolic mechanisms linking diabetes mellitus to accelerated calcific aortic valve disease (CAVD) and evaluates their therapeutic implications. Despite the absence of disease-modifying pharmacotherapy for CAVD, diabetes consistently increases incident aortic stenosis risk (HR 1.3-1.7), calcification burden, and disease severity, independent of traditional cardiovascular risk factors. Epidemiological, imaging, and histological evidence demonstrate that dysglycemia promotes earlier onset, denser valvular calcium deposits, and worse post-intervention outcomes. We delineate seven interconnected and partially overlapping pathways through which diabetes remodels the aortic valve: hyperglycemia-driven valvular interstitial cell (VIC) phenotypic switching and insulin resistance; advanced glycation end-product-RAGE signaling; oxidative stress and mitochondrial dysfunction; macrophage NLRP3-IL-1β inflammasome activation; endothelial barrier compromise; BMP-Runx2-Wnt-Notch osteogenic reprogramming; and CKD-mineralocorticoid receptor cross-talk. These processes convert metabolic stress into sustained valvular inflammation, matrix remodeling, and ectopic ossification. Mechanistic and observational data provide a rationale for evaluating metformin, SGLT2 inhibitors, IL-1β/NLRP3 inhibitors, and Lp(a)-lowering strategies as candidate approaches to modulate calcification progression. Integrated metabolic-inflammatory-imaging biomarkers offer potential for risk stratification and trial enrichment. This immunometabolic framework identifies actionable nodes and underscores the urgent need for dedicated, valve-focused randomized trials in diabetic CAVD to translate mechanistic insights into clinical benefit.