Heparin is the mainstay of therapy for acute venous thromboembolism during pregnancy; its large molecular weight prevents it from crossing the placenta, reducing the risks of fetal hemorrhage and teratogenesis. However, in nonpregnant patients with massive PE causing hemodynamic instability, thrombolytics, IVC filters, or embolectomy are considered. These strategies may be useful during pregnancy as well [2, 3]. In our patient who developed bilateral massive PE during her second trimester, emergency thrombectomy was performed, as heparin therapy was ineffective.
Cardiac surgery during pregnancy carries significant maternal and fetal risks. Since emergent surgery carries a higher risk of maternal mortality, it is usually considered after failure of medical therapy or in critical cases [2, 4]. Conversely, cardiac surgery can be performed with relative safety owing to recent advances in surgical techniques and CPB [3, 5]. Thromboembolism is fatal in nearly 15% of patients with PE during pregnancy, with two-thirds of deaths occurring within 30 min after the embolic event [6]. In our case, cardiopulmonary arrest following anesthesia occurred likely due to the exacerbation of PE. Therefore, close attention should be paid to sudden hemodynamic changes in cases of PE.
Although mortality is equal among pregnant and non-pregnant women, fetal mortality increases in cases of CPB [7, 8]. CPB may have deleterious effects on the uteroplacental blood flow and the fetus due to activation of inflammatory processes, non-pulsatile flow, hypotension, and hypothermia. The fetal heart rate may decrease during CPB; therefore, uterine tone and fetal heart rate should be closely monitored, especially if the fetus is viable. It is recommended to keep the pump flow rate and perfusion pressure to maintain appropriate uteroplacental blood flow during CPB [9].
In our case, an intracardiac echography probe was inserted via the femoral vein and fixed at the position where the umbilical arterial pulse wave could be monitored by Doppler ultrasound. Although the use of intracardiac echography for fetal heart rate monitoring has not been previously reported, we used it because monitoring fetal heart rate with sterile precautions was necessary during CPB. We carefully inserted it after ensuring the absence of thrombosis and obtained informed consent for this procedure after surgery. It allowed us to monitor the fetal heart rate maintaining the sterile surgical field, which is difficult in conventional abdominal monitoring. The intracardiac echography revealed a decline in the fetal heart rate during maternal cardiopulmonary arrest occurred. Although the obstetrician was on standby in the operating room, emergency delivery was not required as the fetal heart rate recovered following the establishment of CPB and was maintained thereafter. We also successfully maintained the average pump perfusion pressure above 70 mmHg.
Maternal and fetal survival rates after emergency cardiac surgery during pregnancy have improved [5], and the number of patients continuing to parturition after surgery has increased. However, there are few reports on delivery of pregnant women after thoracotomy. In general, exercise and traction on the sternum should be avoided within 3 months of thoracotomy [10]. The vaginal route is therefore generally preferred for delivery of a pregnant woman with cardiac disease. Epidural analgesia inhibits pain during delivery and reduces endogenous catecholamines and peripheral vascular resistance, leading to a decrease in cardiac load [11, 12]. In our case, we successfully placed an epidural catheter to administer analgesia during labor, and vacuum extraction was performed to reduce the load secondary to straining.
