Background: Women have poorer in-hospital outcomes following coronary artery bypass grafting compared with men although the reasons are unclear. Gender-mediated differences in the vascular reactivity of the arterial conduit may contribute to these differential outcomes. This study investigated gender-dependent differences in the vasoconstrictor responses of the internal mammary artery used for coronary artery bypass grafting.
Methods: Internal mammary artery segments were obtained from patients undergoing coronary artery bypass grafting and subjected to vascular myography. Following assessment of endothelial function, concentration-response curves were determined to noradrenaline, phenylephrine, seotonin, U46619 (thromboxane analogue) and endothelin. The EC50 values for each vasoconstrictor are summarised in the table below, expressed as mean ± SEM (*significant difference between males and females, p < 0.05).
Tabled
1
| Males (n = 13) | Females (n = 7) | |
|---|---|---|
| Noradrenaline | 0.73 ± 0.25 μM | 0.23 ± 0.40 μM |
| Phenylephrine | 3.36 ± 0.29 μM | 0.36 ± 0.22 μM* |
| U46619 | 11.29 ± 0.12 nM | 2.32 ± 0.41 nM* |
| Serotonin | 4.08 ± 0.27 μM | 0.16 μM ± 0.10 μM* |
| Endothelin | 9.36 ± 1.05 nM | 7.65 ± 1.49 nM |
Conclusion: The internal mammary arteries of women are more sensitive to constriction by thromboxane, phenylephrine and serotonin, compared with men. Ongoing studies are evaluating the molecular mechanisms responsible for these differences.
Article info
Identification
Copyright
© 2011 Published by Elsevier Inc.
