Peripartum Cardiomyopathy: Current Knowledge and Future Directions

Respiratory Diseases of Pregnancy

Pregnant patients can suffer from the same respiratory diseases as the general population in addition to unique syndromes of pregnancy (such as pre-eclampsia and tocolytic induced pulmonary edema, and pregnancy induced cardiomyopathy). Pregnancy by itself may add certain challenges such as difficult intubation. The critically ill pregnant patient requires a multidisciplinary approach and early inclusion of obstetrical expertise is paramount in managing these patients especially in the third trimester.

The effect of parity on longitudinal maternal hemodynamics

BACKGROUND

Parous women have a lower risk for pregnancy complications, such as preeclampsia or delivery of small-for-gestational-age neonates. However, parous women are a heterogeneous group of patients because they contain a low-risk cohort with previously uncomplicated pregnancies and a high-risk cohort with previous pregnancies complicated by preeclampsia and/or small for gestational age. Previous studies examining the effect of parity on maternal hemodynamics, including cardiac output and peripheral vascular resistance, did not distinguish between parous women with and without a history of preeclampsia or small for gestational age and reported contradictory results.

OBJECTIVE

The objective of the study was to compare maternal hemodynamics in nulliparous women and in parous women with and without previous preeclampsia and/or small for gestational age.

STUDY DESIGN

This was a prospective, longitudinal study of maternal hemodynamics, assessed by a bioreactance method, measured at 11⁺⁰ to 13⁺⁶, 19⁺⁰ to 24⁺⁰, 30⁺⁰ to 34⁺⁰, and 35⁺⁰ to 37⁺⁰ weeks' gestation in 3 groups of women. Group 1 was composed of parous women without a history of preeclampsia and/or small for gestational age (n = 632), group 2 was composed of nulliparous women (n = 829), and group 3 was composed of parous women with a history of preeclampsia and/or small for gestational age (n = 113). A multilevel linear mixed-effects model was performed to compare the repeated measures of hemodynamic variables controlling for maternal characteristics, medical history, and development of preeclampsia or small for gestational age in the current pregnancy.

RESULTS

In groups 1 and 2, cardiac output increased with gestational age to a peak at 32 weeks and peripheral vascular resistance showed a reversed pattern with its nadir at 32 weeks; in group 1, compared with group 2, there was better cardiac adaptation, reflected in higher cardiac output and lower peripheral vascular resistance. In group 3 there was a hyperdynamic profile of higher cardiac output and lower peripheral vascular resistance at the first trimester followed by an earlier sharp decline of cardiac output and increase of peripheral vascular resistance from midgestation. The incidence of preeclampsia and small for gestational age was highest in group 3 and lowest in group 1.

CONCLUSION

There are parity-specific differences in maternal cardiac adaptation in pregnancy.

A contemporary review of peripartum cardiomyopathy

Peripartum cardiomyopathy reflects the presence of cardiac failure in the absence of determinable heart disease and occurs in late third trimester of pregnancy or up to 6 months postpartum. A full understanding of pathophysiological mechanisms is lacking, but excess prolactin levels, haemodynamic alterations, inflammation and nutritional deficiencies have all been implicated. Its clinical presentation has distinct overlap with physiological alterations in healthy pregnancy and this presents a diagnostic challenge. However, echocardiography can provide significant benefit in accurate assessment and narrowing of differentials. Pharmacotherapy is broadly aligned with established guidelines for cardiac failure, but specific therapies are indicated for treatment of clinical sequelae. Moreover, an individualistic approach is required based on clinical context to manage delivery. Further research appears imperative to optimise management strategies and reduce disease burden.