Treating blunt aortic injuries with endografts: pros and cons of a meta-analysis

Modern management of blunt aortic injury (BAI) is based on evidence from mostly well-conducted meta-analyses as surrogates for prospective randomized controlled trials. There are several obvious pros and cons to this strategy. The advantages rest on the fact that it is unlikely that a prospective randomized trial comparing open surgical repair with endovascular repair will ever be conducted based on ethical grounds and the apparent survival advantage and reduced paraplegia rates associated with an endovascular approach; pooled data from high-volume studies provides for higher statistical power; and a well-conducted meta-analysis provides the ability to control for inter-study variation. The disadvantages of this approach are that meta-analyses are statistical examinations of scientific studies and not scientific studies in and of themselves; sources of bias cannot be controlled by the method of the analysis; and a heavy reliance on published studies can create exaggerated outcomes. Nonetheless, the studies reviewed in this article offer the best glimpse yet at the truth. The evidence grade to support endovascular over open repair for BAI is Level II (intermediate), which suggests that the described effect is plausible but is not quantified precisely or may be vulnerable to bias. The recommendation grade is B (provisional recommendation), which suggests that on balance of the evidence, endovascular repair for BAI is recommended with caution.