Summary
MicroRNAs are small non-coding RNAs that are detectable in plasma and serum. Circulating
levels of microRNAs have been measured in various studies related to cardiovascular
disease. Heparin is a potential confounder of microRNA measurements due to its known
interference with polymerase chain reactions. In this study, platelet-poor plasma
was obtained from patients undergoing cardiac catheterisation for diagnostic coronary
angiography, or for percutaneous coronary intervention, both before and after heparin
administration. Heparin had pronounced effects on the assessment of the exogenous
C. elegans spike-in control (decrease by approx. 3 cycles), which disappeared 6 hours after
the heparin bolus. Measurements of endogenous microRNAs were less sensitive to heparin
medication. Normalisation of individual microRNAs with the average cycle threshold
value of all microRNAs provided a suitable alternative to normalisation with exogenous
C. elegans spike-in control in this setting. Thus, both the timing of blood sampling relative
to heparin dosing and the normalisation procedure are critical for reliable microRNA
measurements in patients receiving intravenous heparin. This has to be taken into
account when designing studies to investigate the relation of circulating microRNAs
to acute cardiovascular events or coronary intervention.
Keywords
Cardiology - coronary syndrome - clinical trials - heparins