Vascular endothelial growth factor release following coronary artery bypass surgery: extracorporeal circulation versus 'beating heart' surgery

Aims The aim of this study was to examine the circulating levels of vascula r endothelial growth factor, following coronary artery bypass graft surgery performed using both standard cardiopulmonary bypass or the 'octopus techn ique' on the beating heart. Background Vascular endothelial growth factor has a number of effects that are beneficial in the setting of coronary artery bypass graft surgery inclu ding cardio-protection, potent angiogenic activity and amelioration of inti mal hyperplasia. Hypoxia is a powerful stimulator of vascular endothelial g rowth factor expression yet the ability of ischaemia, occurring during coro nary artery bypass graft surgery, to induce vascular endothelial growth fac tor production is unknown. Methods and Results Serum vascular endothelial growth factor levels were de termined in patients undergoing coronary artery bypass graft surgery with s tandard cardiopulmonary bypass (CPB-CABG group; n=20), with off-pump corona ry artery bypass; (OP-CABG; n=12) and in patients undergoing non-cardiac ma jor surgery (n=6). The effect of hypoxia on vascular endothelial growth fac tor release by neonatal rat cardiac myocytes in vitro was studied. In the CPB-CABG group vascular endothelial growth factor levels were signif icantly increased to 78.5 +/- 39.3 and 110.5 +/- 16.3 pg.mu l(-1) 8 and 24 h post-operatively, declining to 14.9 +/- 9.9 pg.mu l(-1) by 48 h to pre-op erative values (14.4+/-8.6 pg.mu l(-1)). Significantly higher vascular endo thelial growth factor levels were also present in the OP-CABG group 3, 6 an d 24 h post-operatively (levels 136.6 +/- 29.3, 143 +/- 26.12 pg.mu l(-1) a nd 93.5 +/- 20.1 pg.mu l(-1) respectively). However, non-cardiac major surg ery did not result in elevated vascular endothelial growth factor levels po st-operatively (46.36+/-9.76 vs pre-surgery levels of 26.84 +/- 6.1 pg.mu l (-1)). Either 15 min or 3 h of hypoxia stimulated vascular endothelial grow th factor release from neonatal rat cardiac myocytes in vitro. Twenty-four and 48 h post hypoxia, levels of vascular endothelial growth factor were si gnificantly elevated by approximately 17.5-and 48.5-fold respectively. Conclusions These data demonstrate myocardial ischaemia secondary to CPB-CA BG and OP-CABG to be a potent stimulator of vascular endothelial growth fac tor production, which may have implications for graft endothelialization an d cardiovascular haemodynamics post-operatively. (C) 2000 The European Soci ety of Cardiology.