Background Although self‐expandable metal stent (SEMS) placement as bridge to surgery (BTS) in patients with left‐sided obstructing colonic cancer has shown promising short‐term results, it is used infrequently owing to uncertainty about its oncological safety. This population study compared long‐term oncological outcomes between emergency resection and SEMS placement as BTS. Methods Through a national collaborative research project, long‐term outcome data were collected for all patients who underwent resection for left‐sided obstructing colonic cancer between 2009 and 2016 in 75 Dutch hospitals. Patients were identified from the Dutch Colorectal Audit database. SEMS as BTS was compared with emergency resection in the curative setting after 1 : 2 propensity score matching. Results Some 222 patients who had a stent placed were matched to 444 who underwent emergency resection. The overall SEMS‐related perforation rate was 7·7 per cent (17 of 222). Three‐year locoregional recurrence rates after SEMS insertion and emergency resection were 11·4 and 13·6 per cent (P = 0·457), disease‐free survival rates were 58·8 and 52·6 per cent (P = 0·175), and overall survival rates were 74·0 and 68·3 per cent (P = 0·231), respectively. SEMS placement resulted in significantly fewer permanent stomas (23·9 versus 45·3 per cent; P < 0·001), especially in elderly patients (29·0 versus 57·9 per cent; P < 0·001). For patients in the SEMS group with or without perforation, 3‐year locoregional recurrence rates were 18 and 11·0 per cent (P = 0·432), disease‐free survival rates were 49 and 59·6 per cent (P = 0·717), and overall survival rates 61 and 75·1 per cent (P = 0·529), respectively. Conclusion Overall, SEMS as BTS seems an oncologically safe alternative to emergency resection with fewer permanent stomas. Nevertheless, the risk of SEMS‐related perforation, as well as permanent stoma, might influence shared decision‐making for individual patients.

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There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed. Interestingly, no major differences were observed between the aortic and pulmonary valves. Valve annulus and leaflet dimensions increase throughout life. The typical three-layered leaflet structure is present before birth, but becomes more distinct with age. After birth, cell numbers decrease rapidly, while remaining cells obtain a quiescent phenotype and reside in the ventricularis and spongiosa. With age and maturation–but more pronounced in aortic valves–the matrix shows an increasing amount of collagen and collagen cross-links and a reduction in glycosaminoglycans. These matrix changes correlate with increasing leaflet stiffness with age. Our data provide a new and comprehensive overview of the changes of structure-function properties of fetal to adult human semilunar heart valves that can be used to evaluate and optimize future therapies, such as tissue engineering of heart valves. Changing hemodynamic conditions with age can explain initial changes in matrix composition and consequent mechanical properties, but cannot explain the ongoing changes in valve dimensions and matrix composition at older age.

Promising mitral valve (MV) repair concepts include leaflet augmentation and saddle shaped annuloplasty, and recent long-term studies have indicated that excessive tissue stress and the resulting strain-induced tissue failure are important etiologic factors leading to the recurrence of significant MR after repair. In the present work, we are aiming at developing a high-fidelity computational framework, incorporating detailed collagen fiber architecture, accurate constitutive models for soft valve tissues, and micro-anatomically accurate valvular geometry, for simulations of functional mitral valves which allows us to investigate the organ-level mechanical responses due to physiological loadings. This computational tools also provides a means, with some extension in the future, to help the understanding of the connection between the repair-induced altered stresses/strains and valve functions, and ultimately to aid in the optimal design of MV repair procedure with better performance and durability.

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