Validation of the 6-minute walk in patients with pulmonary arterial hypertension: trying to fit a square PEG into a round hole?

OK – I know what you are thinking. How could the editors have chosen someone with my well-known views on the 6-minute walk (6MW) to write an editorial on the subject? Well, remember that data should always trump bias, and I can hopefully assess the existent data and the manuscript by Gabler et al1 (although it does, at least in part, uphold my views) in an unbiased fashion. For the purpose of this discussion, I will examine several points related to the use of the 6MW in patients with pulmonary arterial hypertension (PAH) and in the clinical trials examining the effect of treatment in this disease entity.