Cardiac troponin levels in pregnant women with severe pre-eclampsia

Cardiac-specific troponins in uncomplicated pregnancy and pre-eclampsia: A systematic review

Background

The risk of myocardial infarction (MI) increases during pregnancy, particularly in women with pre-eclampsia. MI is diagnosed by measuring high blood levels of cardiac-specific troponin (cTn), although this may be elevated in women with pre-eclampsia without MI, which increases diagnostic uncertainty. It is unclear how much cTn is elevated in uncomplicated and complicated pregnancy, which may affect whether the existing reference intervals can be used in pregnant women. Previous reviews have not investigated high-sensitivity troponin in pregnancy, compared to older, less sensitive methods.

Methods

Electronic searches using the terms “troponin I” or “troponin T”, and “pregnancy”, “pregnancy complications” or “obstetrics”. cTn levels were extracted from studies of women with uncomplicated pregnancies or pre-eclampsia.

Results

The search identified ten studies with 1581 women. Eight studies used contemporary methods that may be too insensitive to use reliably in this clinical setting. Two studies used high-sensitivity assays, with one reporting an elevation in troponin I (TnI) in pre-eclampsia compared to uncomplicated pregnancy, and the other only examining women with pre-eclampsia.

Seven studies compared cTn between women with pre-eclampsia or uncomplicated pregnancy using any assay. Seven studies showed elevated TnI in pre-eclampsia compared to uncomplicated pregnancy or non-pregnant women. One study measured troponin T (TnT) in pregnancy but did not examine pre-eclampsia.

Conclusion

TnI appears to be elevated in pre-eclampsia, irrespective of methodology, which may reflect the role of cardiac stress in this condition. TnI may be similar in healthy pregnant and non-pregnant women, but we found no literature reporting pregnancy-specific reference intervals using high-sensitivity tests. This limits broader application of cTn in pregnancy. There is a need to define reference intervals for cTn in pregnant women, which should involve serial sampling throughout pregnancy, with careful consideration for gestational age and body mass index, which cause dynamic changes in normal maternal physiology.

Markers of maternal cardiac dysfunction in pre-eclampsia and superimposed pre-eclampsia

AUTHORS

Frances Conti-Ramsden MBBS Academic Clinical Fellow¹, Carolyn Gill PhD BRC Research Assistant¹, Paul T Seed MSc CStat Senior Lecturer in Medical Statistics¹, Kate Bramham PhD Clinical Senior Lecturer in Nephrology^2, Lucy C Chappell PhD NIHR Research Professor in Obstetrics¹, Fergus P McCarthy PhD Clinical Senior Lecturer in Obstetrics and Gynaecology^1,3.

OBJECTIVES

To determine whether glycogen phosphorylase isoenzyme B (GPBB) and/or brain natriuretic peptide (BNP) concentrations are elevated in pre-eclampsia and superimposed pre-eclampsia (SPE), demonstrating cardiac ischaemia and strain.

STUDY DESIGN

A nested case-control study was performed using samples and clinical data available from a prospective pregnancy cohort. Four groups were selected: healthy pregnant controls (n = 21), pre-eclampsia (n = 19), pre-existing chronic hypertension (CHT) and/or chronic kidney disease (CKD) without (n = 20) or with superimposed pre-eclampsia (SPE) (n = 19). Plasma samples were taken at time of disease or the third trimester in controls.

MAIN OUTCOME MEASURES

Plasma concentrations of GPBB and BNP.

RESULTS

There was no significant difference in GPBB plasma concentrations between controls and pre-eclampsia (geometric mean (GM) [95% CI]: 4.74 [2.54-8.84]ng/mL vs 5.01 [2.58-9.74]ng/mL, p = 0.90)), or between CHT and/or CKD and SPE (GM [95% CI]: 9.49 [4.93-18.25]ng/mL vs 10.24 [5.27-19.92]ng/mL, p = 0.87). BNP plasma concentrations were significantly raised in women with pre-eclampsia compared to controls (GM [95% CI]: 31.83 [20.18-50.22]pg/mL vs 11.33 [7.34-17.51]pg/mL, p = 0.001). Women with CKD, but not CHT, who developed SPE had elevated BNP concentrations. There were no significant differences in BNP concentration between women with comorbidity (CHT and/or CKD) and controls.

CONCLUSIONS

GPBB has a limited role as a biomarker in hypertensive disorders of pregnancy. BNP concentrations were elevated in pre-eclampsia compared to controls. This suggests cardiac strain at the time of pre-eclampsia. Further studies are needed to examine whether BNP can identify women at increased risk of cardiovascular disease.

Changes in biochemical tests in pregnancy and their clinical significance

Interpretation of laboratory investigations relies on reference intervals. Physiological changes in pregnancy may result in significant changes in normal values for many biochemical assays, and as such results may be misinterpreted as abnormal or mask a pathological state. The aims of this review are as follows: 1. To review the major physiological changes in biochemical tests in normal pregnancy. 2. To outline where these physiological changes are important in interpreting laboratory investigations in pregnancy. 3. To document the most common causes of abnormalities in biochemical tests in pregnancy, as well as important pregnancy-specific causes.

Review article: Investigations and the pregnant woman in the emergency department - part 1: Laboratory investigations

Accurate assessment of the pregnant patient in the ED depends on knowledge of physiological changes in pregnancy, and how these changes may impact on pathology tests, appearance on point-of-care ultrasound and electrocardiography. In addition the emergency physician needs to be cognisant of disorders that are unique to or more common in pregnancy. Part 1 of this review addresses potential deviations in laboratory investigation reference intervals resulting from physiological alterations in pregnancy, and the important causes of abnormal laboratory results in pregnancy. Part 2 will address the role of point-of-care ultrasound in pregnancy, physiological changes that may affect interpretation of point-of-care ultrasound, physiological changes in electrocardiography, and the safety of radiological procedures in the pregnant patient.

The Role of Cardiac Biomarkers in Pregnancy

OPINION STATEMENT

Cardiovascular disease (CVD) is the leading cause of pregnancy-associated mortality, with an increasingly complex pregnant population. While our understanding of CVD in pregnancy continues to evolve, there remains a need to develop widely accessible tools to follow pregnant women both with and without preexisting disease with respect to cardiovascular risk, particularly for those presenting with symptoms suggestive of cardiovascular pathology. Thus, research is emerging with respect to the potential role of novel and established cardiac biomarkers in diagnosing and following CVD in pregnancy. Here, we review the normal hemodynamics of pregnancy and the behavior of various biomarkers in both normal and complicated pregnancies.

Shared biomarkers between female diastolic heart failure and pre-eclampsia: a systematic review and meta-analysis

Evidence accumulates for associations between hypertensive pregnancy disorders and increased cardiovascular risk later. The main goal of this study was to explore shared biomarkers representing common pathogenic pathways between heart failure with preserved ejection fraction (HFpEF) and pre‐eclampsia where these biomarkers might be potentially eligible for cardiovascular risk stratification in women after hypertensive pregnancy disorders. We sought for blood markers in women with diastolic dysfunction in a first literature search, and through a second search, we investigated whether these same biochemical markers were present in pre‐eclampsia.This systematic review and meta‐analysis presents two subsequent systematic searches in PubMed and EMBASE. Search I yielded 3014 studies on biomarkers discriminating women with HFpEF from female controls, of which 13 studies on 11 biochemical markers were included. Cases had HFpEF, and controls had no heart failure. The second search was for studies discriminating women with pre‐eclampsia from women with non‐hypertensive pregnancies with at least one of the biomarkers found in Search I. Search II yielded 1869 studies, of which 51 studies on seven biomarkers were included in meta‐analyses and 79 studies on 12 biomarkers in systematic review.Eleven biological markers differentiated women with diastolic dysfunction from controls, of which the following 10 markers differentiated women with pre‐eclampsia from controls as well: C‐reactive protein, HDL, insulin, fatty acid‐binding protein 4, brain natriuretic peptide, N terminal pro brain natriuretic peptide, adrenomedullin, mid‐region pro adrenomedullin, cardiac troponin I, and cancer antigen 125.Our study supports the hypothesis that HFpEF in women shares a common pathogenic background with pre‐eclampsia. The biomarkers representing inflammatory state, disturbances in myocardial function/structure, and unfavourable lipid metabolism may possibly be eligible for future prognostic tools.

High-sensitivity troponin T predicts worsening of albuminuria in hypertension; results of a nested case-control study with confirmation in diabetes

OBJECTIVE

Hypertension is an important cause of end-stage renal disease. Development of microalbuminuria is the first clinical sign of renal dysfunction, progressing to macroalbuminuria and eventually resulting in end-stage renal disease (ESRD). Markers that could predict the development of microalbuminuria or macroalbuminuria beyond traditional risk markers would allow for earlier intervention and better prevention of ESRD. We investigated in a case-control study whether circulating levels of the micronecrosis marker high-sensitivity troponin T (hs-TnT) add to predicting the development of microalbuminuria or macroalbuminuria in hypertensive patients and performed a replication study in type 2 diabetic individuals (T2DM).

METHODS

Cases and controls were extracted from a large (N = 8592) general population cohort with long-term follow-up and repeated measurement of albuminuria (PREVEND-study). Cases were defined by transition in albuminuria stage, that is, from normoalbuminuria to microalbuminuria or from microalbuminuria to macroalbuminuria (average follow-up 2.8 years). Controls with stable albuminuria were pair-matched for age, sex, and albuminuria-status. Hs-TnT was measured at baseline in 75 case/control pairs with hypertension and 33 case/control pairs with T2DM.

RESULTS

Prior to transition in albuminuria, hs-TnT was higher in cases than in controls [6.6 (3.1-11.6) vs. 5.3 (2.9-8.6) pg/ml, P = 0.05]. The odds for transition in albuminuria increased significantly per SD increase in hs-TnT [2.2 (1.2-4.3), P = 0.02]. In addition, hs-TnT improved prediction of albuminuria transition, with significant increases in integrated discrimination improvement of 0.048, P = 0.02. Similar results were found in the T2DM case-control cohort.

CONCLUSION

We identified hs-TnT as an independent marker predicting the transition in albuminuria stage in hypertension beyond conventional risk-markers. These findings were confirmed in patients with T2DM.

Hypertension in pregnancy: a comprehensive update

Hypertensive disorders of pregnancies remain a central public health concern throughout the world, and are a major cause of maternal mortality in the developing world. Although treatment options have not significantly changed in recent years, insight on the pathogenesis of preeclampsia/eclampsia has been remarkable. With improved animal models of preeclampsia and large-scale human trials, we have embarked upon a new era where angiogenic biomarkers based on mechanism of disease can be designed to assist in early diagnosis and treatment. There is also a growing recognition of how elusive the diagnosis of eclampsia can be, especially in the postpartum period. Proper treatment of these patients depends heavily on the correct diagnosis, especially by the emergency physician. Finally, large epidemiologic studies have revealed that preeclampsia, once thought to be a self-limited entity, now appears to portend real damage to the cardiovascular and other organ systems in the long term. This review will present the latest update on our understanding of the various hypertensive disorders of pregnancies and their treatment options.