Why the study?
Does protamine infusion affect epicardial microflow and graft flow in patients undergoing open-heart surgery?
Observational
Does protamine infusion affect epicardial microflow and graft flow in patients undergoing open-heart surgery?
p-value: p=<0.002
Protamine infusion during open-heart surgery initially increases but subsequently reduces epicardial microcirculation and graft flow, suggesting it contributes to postoperative graft flow reduction.
May warrant graft flow monitoring after protamine in CABG; hypothesis-generating and requires prospective validation.
To evaluate the effect of coronary revascularization on myocardial perfusion and surgical outcome regarding graft flow, we used laser Doppler flowmetry to assess the epicardial microcirculation in patients undergoing coronary artery bypass grafting (CABG) or valve replacement (VR) and electromagnetic flowmetry to measure graft flow in the CABG group. In the CABG group, the preoperative mean laser Doppler flow rate (LDF) in the epicardium of the left ventricle significantly increased at the end of cardiopulmonary bypass (CPB) (22 +/- 7 arbitrary units (AU) to 60 +/- 13 AU, p < 0.001). This value further increased 10 min after protamine infusion (66 +/- 14 AU, p < 0.01), but was significantly reduced 30 min later (51 +/- 14 AU, p < 0.002). Compared to the post-CPB value (34 +/- 10 ml/min) before protamine infusion, the mean graft flow (ml/min) to this area significantly increased 10 min after protamine infusion (41.3 +/- 10 ml/min, p < 0.001) but significantly decreased 30 min later (29 +/- 9 ml/min, p < 0.001). The preoperative mean LDF in the VR group was significantly higher than in the CABG group (p < 0.01). In the CABG group, there was a positive correlation between the LDF and graft flow at the end of CPB (r = 0.788) and 10 (r = 0.767) and 30 (r = 0.784) min after protamine infusion. This study shows that coronary bypass grafting increases the myocardial microcirculation which, together with graft flow, could give an early indication of the effect of surgery on myocardial microcirculation. Furthermore, protamine was found to be one of the factors contributing to graft flow reduction postoperatively and, therefore, newer methods of heparin reversal may be desirable.
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Belboul et al. (1997) conducted an observational in Coronary artery disease or valvular heart disease requiring surgery. Protamine infusion vs. Before protamine infusion (post-cardiopulmonary bypass) was evaluated on Epicardial microcirculation (laser Doppler flow rate) and graft flow (p=<0.002).
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