Key result
Björk-Shiley CC valves welded 1981–1984 linked to ~5-fold higher fracture rate than pre-1981 valves.
Why the study?
The association between outlet strut fracture and welder identity and weld date of Björk-Shiley convexo-concave valves was unclear.
Does welder identity or weld date affect the risk of outlet strut fracture in Björk-Shiley convexo-concave valves?
Cohort (n=2,266)
Does welder identity or weld date affect the risk of outlet strut fracture in Björk-Shiley convexo-concave valves?
Welder identity does not contribute to the risk of strut fracture in Björk-Shiley convexo-concave valves, but valves produced between 1981 and 1984 carry a higher risk.
Answers are grounded in this paper and cite their sources.
Supports era-specific monitoring for 1981-1984 Björk-Shiley valves; extends evidence by excluding welder identity as a risk factor.
OBJECTIVE: To establish whether there is an association between subsequent fracture of the outlet strut and welder identity and the weld date of Björk-Shiley convexo-concave (BScc) valves. DESIGN: Cohort study. PATIENTS: All Dutch BScc valve recipients (n = 2266). MEAN OUTCOME MEASURES: Documented outlet strut fracture during follow up. RESULTS: Weld dates were known for 97.0% of all BScc valves (n = 2534) implanted in Dutch patients (n = 2266) and welder identity was known for 52.2%. During a mean follow up of 9.4 years, 46 fractures were documented. For 60 degrees valves welded from 1981 to 1984 the fracture rate (0.22 per 100 person-years (95% CI 0.13 to 0.34)) was higher than that for valves welded before 1981 (0.04 (95% CI 0.01-0.10)). When all fracture related risk factors were taken into account, fracture rates per welder did not show any statistically significant differences. CONCLUSIONS: Welder identity does not contribute to the risk of strut fracture. Other factors in the production of BScc valves may explain the increased risk for valves welded from 1981 to 1984.
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Kallewaard et al. (1996) conducted a cohort in Björk-Shiley convexo-concave (BScc) valve recipients (n=2,266). Weld date from 1981 to 1984 vs. Weld date before 1981 was evaluated on Documented outlet strut fracture during follow up. Björk-Shiley convexo-concave valves welded from 1981 to 1984 had a higher fracture rate (0.22 per 100 person-years) than those welded before 1981 (0.04 per 100 person-years).
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