Can pregnant women be safely placed on cardiopulmonary bypass?

Abstract

A best evidence topic was written according to a structured protocol. The question addressed was whether cardiopulmonary bypass can be used safely with satisfactory maternal and foetal outcomes in pregnant patients undergoing cardiac surgery. A total of 679 papers were found using the reported searches of which 14 represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were maternal and foetal mortality and complications, mode of delivery, cardiopulmonary bypass and aortic cross-clamp times, perfusate flow rate and temperature and maternal NYHA functional class. The most recent of the best evidence studies, a retrospective observational study of 21 pregnant patients reported early and late maternal mortalities of 4.8 and 14.3%, respectively, and a foetal mortality of 14.3%. Median cardiopulmonary bypass and aortic cross-clamp times were 53 and 35 min, respectively, and the median bypass temperature was 37°C. Three larger retrospective reviews of the literature reported maternal mortality rates of 2.9-5.1% and foetal mortality rates of 19-29%. Mean cardiopulmonary bypass times ranged from 50.5 to 77.8 min. Another retrospective observational study reported maternal mortality of 13.3% and foetal mortality of 38.5%. Mean cardiopulmonary bypass and aortic cross-clamp times were 89.1 and 62.8 min, respectively, with a mean bypass temperature of 31.8°C. A retrospective case series reported no maternal mortality and one case of foetal mortality. Median cardiopulmonary bypass and aortic cross-clamp times were 101 and 88 min, respectively. Eight case reports described 10 patients undergoing cardiopulmonary bypass. There were no reports of maternal mortality and one report of foetal mortality. Mean cardiopulmonary bypass and aortic cross-clamp times were 105 and 50 min, respectively. We conclude that while the use of cardiopulmonary bypass during pregnancy poses a high risk for both the mother and the foetus, the use of high-flow, high-pressure, pulsatile, normothermic bypass and continuous foetal and uterine monitoring can allow cardiac surgery with the use of cardiopulmonary bypass to be performed with the greatest control of risk in the pregnant patient.