Abstract：
Understanding of the mechanisms contributing to the increased maternal susceptibility for major adverse cardiovascular events in the postpartum period remains poor. Accordingly, this study tested the hypothesis that the balance between coronary blood flow and myocardial metabolism is compromised during the puerperium period (35-45 days post-delivery) in swine. Systemic and coronary hemodynamic responses were assessed in anesthetized, open-chest control (nonpregnant) and puerperium/postpartum swine at baseline and in response to intravenous infusion of dobutamine (1-30 μg/kg/min). Blood pressure and heart rate were lower in postpartum swine at baseline and in response to dobutamine (P < 0.05). Coronary blood flow and myocardial oxygen delivery were significantly diminished at baseline in postpartum swine (P < 0.001), which corresponded with ∼35% reduction in myocardial oxygen consumption (MVO2) (P < 0.001). Postpartum swine displayed enhanced retrograde coronary flow, larger cardiomyocyte area (P < 0.01) and marked capillary rarefaction (P < 0.01). The relationship between coronary blood flow and heart rate (P < 0.05) or MVO2 (P < 0.001) was significantly diminished in postpartum swine as dobutamine increased MVO2 up to ∼135% in both groups. This reduction in myocardial perfusion was associated with decreases in myocardial lactate uptake (P < 0.001), increases in coronary venous PCO2 (P < 0.01) and decreased coronary venous pH (P < 0.01). These findings suggest an impaired balance between coronary blood flow and myocardial metabolism could contribute to the increased incidence of maternal myocardial ischemia and premature death in the postpartum period.
摘要：
对导致产妇在产后期间对主要不良心血管事件的易感性增加的机制的理解仍然很差。因此，这项研究验证了以下假设：猪产褥期（分娩后35-45天）冠状动脉血流和心肌代谢之间的平衡受到损害。全身和冠状动脉血流动力学反应在麻醉评估，在基线和对静脉输注多巴酚丁胺（1-30μg/kg/min）的反应中，进行开胸控制（非妊娠）和产褥期/产后猪。产后猪的血压和心率在基线和多巴酚丁胺反应中均较低（P<0.05）。基线时，产后猪冠状动脉血流量和心肌氧输送显著减少（P<0.001），与心肌耗氧量（MVO2）降低约35％相对应（P<0.001）。产后猪表现出增强的逆行冠状动脉血流，心肌细胞面积较大（P<0.01），毛细血管稀疏明显（P<0.01）。产后猪冠状动脉血流量与心率（P<0.05）或MVO2（P<0.001）之间的关系显着降低，因为多巴酚丁胺使两组的MVO2增加至〜135％。心肌灌注的减少与心肌乳酸摄取的减少有关（P<0.001），冠状静脉PCO2升高(P<0.01),冠状静脉pH降低(P<0.01)。这些发现表明，冠状动脉血流和心肌代谢之间的平衡受损可能导致产后母亲心肌缺血和过早死亡的发生率增加。
