The authors addressed a clear research question supported by appropriate inclusion criteria. The search for published studies was limited; OVID was stated as a database searched, but this is a gateway to a number of databases and it was unclear which were searched. There was no specific search for unpublished studies, so publication bias could not be ruled out. There was no formal quality assessment, although the potential for progression bias was indicated. Study selection was conducted in duplicate; it was unclear whether similar methods were used to reduce error and bias in other parts of the review process. Study quality was not assessed and so the quality of the available evidence was unclear. There were few study details, so it was difficult for the reader to assess the quality of the included studies or the clinical heterogeneity that may have been present. The results for analyses of aortic valve area for the two technologies and the mean difference between these were statistically homogeneous. But, there was substantial statistical heterogeneity across studies in the reported correlation between the two technologies, which indicated some clinical differences between the studies that was not apparent from the limited study details provided. The review was based on few studies with small sample sizes and 19% of participants included in the analyses did not have the target condition. The authors stated implications for practice for target conditions that were not formally assessed in the review. Given the concerns regarding the review process and the size, quality and clinical differences of the included studies, the results and implications for practice should be treated with some caution.