Female patients exhibit altered vasopressin-induced coronary microvascular contractile response and molecular signaling following cardiac surgery.

Background: Emerging data suggest women have worse outcomes than men following cardioplegia and cardiopulmonary bypass (CP/CPB). Altered coronary microvascular function affecting myocardial perfusion may contribute, but human translational studies are lacking.
Methods: Viable coronary microvessels (<200 μ m) were dissected from human atrial samples collected before and after CP/CPB from a subset of 108 patients enrolled. Ex vivo contractile responses to vasopressin were assessed using video microscopy. RNA deep-sequencing and immunoblotting were used to quantify gene and protein expression, respectively.
Results: Coronary microvessels exhibited increased vasopressin-induced contractile responses post-CP/CPB in males and females (p ​< ​0.0001). Females exhibited a decrease in microvascular contractile response versus males pre- (p ​= ​0.1) and post-CP/CPB (p ​= ​0.09) which approached significance. Myocardial vasopressin 1a receptor levels were increased in females versus males (p ​= ​0.001). Vasopressin-induced vasoconstriction predicted postoperative cardiac index.
Conclusions: Impaired coronary microvascular contractile responses in females jeopardizing myocardial perfusion may underlie worse outcomes following cardiac surgery.
Competing Interests: Declaration of interest statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.
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