Limitations
cardiac dyspnea, dyspnea
SECONDARY
This current analysis is a secondary analysis of a randomized controlled trial, which was not powered for the present analysis strategy; generalization is therefore limited. As there was no sham control for PCI, it is not possible to attribute all improvements in symptomatic outcome after PCI exclusively to the PCI. The clinical rating of concomitant cardiac dyspnea is complex in clinical practice and some patients might have been misclassified, but it was investigated carefully by experienced cardiologists in the most appropriate manner. We used the NYHA dyspnea scale to assess dyspnea which is a generally accepted and sufficiently good tool. However, general limitations regarding clinical scales in contrast to objectifiable physiological (e.g., echocardiography) or functional testing (e.g., 6-min walking test, treadmill exercise test) regarding inaccuracy and intra- as well as interpersonal variation do also apply to the NYHA dyspnea scale.