Cardiac surgery during pregnancy: Continuous fetal monitoring using umbilical artery Doppler flow velocity indices

Fetal Doppler monitoring during maternal open-heart surgery: Case report and key aspects of a multidisciplinary challenge

CASE REPORT

Herein we present the case of a 33-year nulliparous woman at 21 weeks of gestation with mitral valve vegetation resulting from infective endocarditis. Due to the mother's critical condition caused by consecutive thromboembolic events, surgery with cardiopulmonary bypass was indicated. During surgery the fetus was monitored by a specialized obstetrician who repetitively measured the Doppler indices of the umbilical artery, Ductus venosus and uterine artery. Right after CO₂ was insufflated into the operating area, the Doppler monitoring showed an increased Pulsatility Index of the Umbilical artery right before fetal distress with bradycardia occurred. A subsequent maternal arterial blood gas analysis showed an acidosis with hypercapnia. Consequently, the CO₂ insufflation was stopped and the gas flow on the Heart Lung Machine increased. After regaining homeostasis of acidosis, the Doppler Indices and fetal heart rate recovered. The remaining surgery and postoperative course were uneventful. At the 37 weeks of gestation a healthy boy was delivered by Cesarean section and at the age of two years, the neurodevelopment was assessed, which indicated normal development in mental cognition, language and motoric. This report presents a periodic Doppler examination of the maternal and fetal circulation during surgery on CPB while also discussing the possible impact of fetal monitoring in managing open cardiac surgery in pregnancy.

Doppler Ultrasound of the Umbilical Artery: Clinical Application

OBJECTIVE

 To provide a survey of relevant literature on umbilical artery Doppler ultrasound use in clinical practice, technical considerations and limitations, and future perspectives.

METHODS

 Literature searches were conducted in PubMed and Medline, restricted to articles written in English. Additionally, the references of all analyzed studies were searched to obtain necessary information.

RESULTS

 The use of this technique as a routine surveillance method is only recommended for high-risk pregnancies with impaired placentation. Meta-analyses of randomized trials have established that obstetric management guided by umbilical artery Doppler findings can improve perinatal mortality and morbidity. The values of the indices of Umbilical artery Doppler decrease with advancing gestational age; however, a lack of consensus on reference ranges prevails.

CONCLUSION

 Important clinical decisions are based on the information obtained with umbilical artery Doppler ultrasound. Future efforts in research are imperative to overcome the current limitations of the technique.

Pregnancy and cardiac interventions: What are the optimal management options?

Cardiac disease is the leading cause of maternal mortality in the United Kingdom. Major causes of cardiac death in pregnant women include cardiomyopathies, myocardial infarction, ischemic heart disease, and aortic dissection. Uncorrected congenital heart disease and women who have had corrective or palliative surgery may have complicated pregnancies as well. Some women with significant cardiac disease are unable to meet the increased physiological demands of pregnancy. Of these, those who do not respond to medical treatment may require surgical correction such as coronary artery bypass grafting. The risk of cardiac operations for pregnant women is similar to that for nonpregnant women but the fetal mortality rate remains high. Contributing factors to high fetal mortality rates include timing, urgency of operation, and the fetal/fetoplacental response to cardiopulmonary bypass. The aim of this review is to summarize current evidence in utilizing the different management approaches of cardiac issues during pregnancy.

A case report: mechanical tricuspid valve thrombosis necessitating cardiac surgery during pregnancy

Background

Pregnant women with mechanical valves are considered a high-risk pregnancy. They carry an increased risk of both maternal and foetal complications. This includes maternal valve thrombosis, foetal embryopathy, and haemorrhage. Cardiac surgery is generally avoided during pregnancy, and is used when there are no other alternative options. Cardiopulmonary bypass (CPB) during pregnancy is associated with high foetal mortality. Maternal mortality in the setting of CPB however, is not dissimilar to a non-pregnant woman.

Case summary

We present the case of a 29-year-old woman with Ebstein’s anomaly who developed thrombosis of her mechanical tricuspid valve at 4 weeks’ gestation. This was suspected to be likely due to sub-therapeutic anticoagulation at the time of presentation. She underwent a tricuspid valve replacement during the first trimester of pregnancy after failing medical therapy, with overall favourable maternal and foetal outcomes.

Discussion

Valve thrombosis during pregnancy is a devastating complication. There is limited data surrounding the best management strategy of valve thrombosis in pregnancy. Cardiac surgery with CPB is reserved for cases refractory to appropriate medical therapy. Though maternal mortality is largely unaffected, foetal mortality with CPB remains high. The management of pregnant women undergoing CPB is unique and extremely challenging. It requires a meticulous, multidisciplinary approach to improve overall outcomes.