Postpartum renal lesions in women with pre-eclampsia

Histopathological features of kidney and renal prognosis in patients with preeclampsia

OBJECTIVE

Understanding the long-term prognosis of preeclampsia (PE) is important. Proteinuria and poor renal function persist in some PE patients, but the relationship between their histopathological findings of kidney and renal prognosis is unknown. Our objective was to clarify the relationship between clinicopathological features and renal prognosis in PE patients.

STUDY DESIGN

Retrospective observational study.

MAIN OUTCOME MEASURES

Seventy patients who had been referred to the Niigata University Hospital between 1977 and 2014 and were diagnosed with PE were classified into unimproved and improved groups. The unimproved group included patients whose serum creatinine level had doubled and/or whose proteinuria had persisted until the end of observation, which included three patients with end-stage kidney disease (ESKD). The improved group included patients whose serum creatinine level did not double and whose proteinuria had disappeared until the last observation. We examined and compared these patients' characteristics, clinical and laboratory findings, and renal histopathological findings from percutaneous kidney biopsies.

RESULTS

There were no significant differences in the clinical backgrounds and clinical findings between the two groups during pregnancy. However, light microscopy findings of their kidney biopsies were able to identify significantly more severe duplications of the capillary loop, interstitial cell infiltration, and interstitial fibrosis in the unimproved group.

CONCLUSIONS

Histopathological examination of the kidney may be a valid method for predicting the long-term prognosis of renal function and for histological a risk assessment of poor renal recovery in PE patients.

Risk of cardiovascular disease, end-stage renal disease, and stroke in postpartum women and their fetuses after a hypertensive pregnancy

Women with hypertensive pregnancy complications are at greater risk of developing cardiovascular disease (CVD), metabolic diseases, stroke, and end-stage renal disease (ESRD) later in life. Pregnancy complications affect not only the mother's long-term health but also the health of the fetus immediately after delivery and into adulthood. The health of the fetus until adulthood can be influenced by developmental programming, in which the fetus is exposed to insults that will ultimately affect the growth of the offspring and increase the offspring's risk of developing hypertension, coronary heart disease, metabolic disease, and chronic kidney disease in adulthood. Preeclampsia, the onset of hypertension during pregnancy, is one of the major risk factors for the development of renal disease, cerebral disease, and CVD in the mother. Women with preeclampsia are at a 5-12-fold increased risk of developing ESRD, 2-fold increased risk of stroke, and 2-fold increased risk of developing CVD later in life. In this review article, we discuss 1) preeclampsia, 2) the risk of developing CVD, renal disease, or stroke later in life for women with hypertensive pregnancies, and 3) the effects of a hypertensive pregnancy on the offspring.

Preeclampsia and ESRD: The Role of Shared Risk Factors

BACKGROUND

Several registry-based studies, using diagnostic codes, have suggested that preeclampsia is a risk factor for end-stage renal disease (ESRD). However, because the 2 diseases share risk factors, the true nature of their association remains uncertain. Our goals were to conduct a population-based study to determine the magnitude of the association between preeclampsia and ESRD and evaluate the role of shared risk factors.

STUDY DESIGN

Population-based nested case-control study.

SETTING & PARTICIPANTS

The US Renal Data System was used to identify women with ESRD from a cohort of 34,581 women who gave birth in 1976 to 2010 in Olmsted County, MN. 44 cases of ESRD were identified and each one was matched to 2 controls based on year of birth (±1 year), age at first pregnancy (±2 years), and parity (±1 or ≥4).

PREDICTOR

Preeclamptic pregnancy, confirmed by medical record review.

OUTCOME

ESRD.

MEASUREMENTS

Prepregnancy serum creatinine and urine protein measurements were recorded. Comorbid conditions existing prior to pregnancy were abstracted from medical records and included kidney disease, obesity, diabetes, and hypertension.

RESULTS

There was evidence of kidney disease prior to the first pregnancy in 9 of 44 (21%) cases and 1 of 88 (<1%) controls. Per chart review, 8 of 44 (18%) cases versus 4 of 88 (5%) controls had preeclamptic pregnancies (unadjusted OR, 4.0; 95% CI, 1.21-13.28). Results were similar after independent adjustment for race, education, diabetes, and hypertension prior to pregnancy. However, the association was attenuated and no longer significant after adjustment for obesity (OR, 3.25; 95% CI, 0.93-11.37).

LIMITATIONS

The limited number of ESRD cases and missing data for prepregnancy kidney function.

CONCLUSIONS

Our findings confirm that there is a sizable association between preeclampsia and ESRD; however, obesity is a previously unexplored confounder. Pre-existing kidney disease was common, but not consistently coded or diagnosed.

Association of proteinuria threshold in pre-eclampsia with maternal and perinatal outcomes: a nested case control cohort of high risk women

OBJECTIVES

To evaluate occurrence of adverse maternal and perinatal outcomes with different thresholds of proteinuria (300-499 mg and ≥500 mg/24 hours) in pre-eclamptic women, comparing outcomes against women with chronic and gestational hypertension.

DESIGN

Secondary analysis of the Vitamins in Pre-Eclampsia Trial.

SETTING

25 UK hospitals in ten geographical areas.

POPULATION

946 women with pre-existing risk factors for pre-eclampsia.

METHODS

Women with pre-eclampsia and proteinuria 300-499 mg/24 h (PE300, referent group, n=60) or proteinuria ≥500 mg/24 h (PE500, n=161) were compared with two groups of non-proteinuric women with chronic hypertension (CHT, n=615) or gestational hypertension (GH, n=110).

MAIN OUTCOME MEASURES

MATERNAL: progression to severe hypertension. Perinatal: small for gestational age (SGA) <5(th) centile, gestation at delivery.

RESULTS

Severe hypertension occurred more frequently in PE500 (35%) and PE300 (27%) than CHT (5.9%; P≤0.01) and GH (10%; p≤0.001). Gestation at delivery was earlier in PE500 (33.2 w) than PE300 (37.3 w; P≤0.001), and later in CHT (38.3 w; P≤0.05) and GH (39.1 w; P≤0.001). SGA infants were more frequent in PE300 (32%) than in CHT (13.3%; P≤0.001) and GH (16.5%; P≤0.05). Women in PE500 were more likely to have a caesarean section than PE300 (78% vs. 48%; P≤0.001), and to receive magnesium sulphate (17% vs. 1.7%, P≤0.05).

CONCLUSION

Women with PE300 have complication rates above those of women managed as out-patients (GH and CHT), meriting closer surveillance and confirming 300 mg/d as an appropriate threshold for determining in-patient management. Adverse perinatal outcomes are higher still in women with PE500.

Renin angiotensin signaling in normal pregnancy and preeclampsia

Many reports indicate that there is an increase in almost all of the components of the renin-angiotensin system (RAS) during an uncomplicated pregnancy, but renin activity, angiotensin II, and aldosterone decrease in preeclampsia (PE) for reasons that are unclear. PE is a life-threatening disorder of late pregnancy characterized by hypertension, proteinuria, increased soluble fms-like tyrosine kinase-1, as well as renal and placental morphologic abnormalities. Although a leading cause of maternal and perinatal morbidity and mortality, the pathogenic mechanisms of PE remain largely undefined. Immunologic mechanisms and aberrations of the RAS have been long considered contributors to the disorder. Bridging these two concepts, numerous studies report the presence of the angiotensin II type I receptor agonistic autoantibody (AT(1)-AA) found circulating in preeclamptic women. This autoantibody induces many key features of the disorder through AT(1) receptor signaling, and has been implicated in the pathogenesis of PE. Here we review the functions of the RAS during normal pregnancy and PE, and highlight the role of AT(1)-AA in both animal models and in the human disorder.

Molecular and vascular targets in the pathogenesis and management of the hypertension associated with preeclampsia

Normal pregnancy is associated with significant hemodynamic changes and vasodilation of the uterine and systemic circulation in order to meet the metabolic demands of the mother and developing fetus. Preeclampsia (PE) is one of the foremost complications of pregnancy and a major cause of maternal and fetal mortality. The pathophysiological mechanisms of PE have been elusive, but some parts of the puzzle have begun to unravel. Genetic factors such as leptin gene polymorphism, environmental and dietary factors such as Ca(2+) and vitamin D deficiency, and co-morbidities such as obesity and diabetes may increase the susceptibility of pregnant women to develop PE. An altered maternal immune response may also play a role in the development of PE. Although the pathophysiology of PE is unclear, most studies have implicated inadequate invasion of cytotrophoblasts into the uterine artery, leading to reduced uteroplacental perfusion pressure (RUPP) and placental ischemia/hypoxia. Placental ischemia induces the release of biologically active factors such as growth factor inhibitors, anti-angiogenic factors, inflammatory cytokines, reactive oxygen species, hypoxia-inducible factors, and antibodies to vascular angiotensin II (AngII) receptor. These bioactive factors could cause vascular endotheliosis and consequent increase in vascular resistance and blood pressure, as well as glomerular endotheliosis with consequent proteinuria. The PE-associated vascular endotheliosis could be manifested as decreased vasodilator mediators such as nitric oxide, prostacyclin and hyperpolarizing factor and increased vasoconstrictor mediators such as endothelin-1, AngII and thromboxane A₂. PE could also involve enhanced mechanisms of vascular smooth muscle contraction including intracellular Ca(2+), and Ca(2+) sensitization pathways such as protein kinase C and Rho-kinase. PE-associated changes in the extracellular matrix composition and matrix metalloproteinases activity also promote vascular remodeling and further vasoconstriction in the uterine and systemic circulation. Some of these biologically active factors and vascular mediators have been proposed as biomarkers for early prediction or diagnosis of PE, and as potential targets for prevention or treatment of the disease.

Acute Renal Failure During Eclampsia: Incidence Risks Factors and Outcome in Intensive Care Unit

OBJECTIVE

To assess the incidence, risk factors and the outcome of acute renal failure (ARF) associated with eclampsia in intensive care unit (ICU).

DESIGN

Prospective and analytic study.

SETTING

A surgical ICU in a university hospital.

PATIENTS

178 consecutive women with eclampsia admitted to an intensive care unit during seven years. ARF was defined by a serum creatinine concentration >140 micromol/L.

RESULTS

The incidence of ARF was 25.8%. In univariate analysis the severity of patient illness, the complications associated with eclampsia (disseminated intravascular coagulation, Hellp syndrome, neurologic complications, abruptio placenta, aspiration pneumonia, delivery hemorrhage) were significantly associated with ARF. In a logistic regression model, risk factors for ARF included organ system failure (OSF) odds ratio (OR)=1.81 confidence interval (CI) [1.08-3.05], bilirubin >12 micromol/L OR=4.42 CI [1.54-12.68], uric acid >5.9 g/dL OR=16.5 CI [3.09-87.94], abruptio placenta OR=0.2 7 CI [0.08-0.99], and oliguria OR=0.10 CI [0.03-0.44]. In contrast, severity of blood pressure or proteinuria on dipstick were not associated with ARF. However, in this series, 15 women required dialysis in the short term and one required long-term dialysis. ARF associated with eclampsia was significantly associated with mortality (32.6% versus 9.1% p=0.0001).

CONCLUSION

ARF with eclampsia is a frequent situation that required intensive management when risks factors were present. The need for dialysis was a rare condition.

A case of "pure" preeclampsia with nephrotic syndrome before 15 weeks of gestation in a patient whose renal biopsy showed glomerular capillary endotheliosis

A 35-year-old Japanese woman for whom a previous health checkup showed normal blood pressure and urinalysis results without serological abnormalities developed nephrotic syndrome with severe hypertension at 15 gestational weeks. The renal biopsy performed at 17 weeks of gestation showed severe glomerular capillary endotheliosis. By means of electron microscopy, no electron-dense deposits were observed in glomeruli, and foot-process arrangement was normal. Histological findings indicated the patient's glomerular damage was caused by the mechanisms of preeclampsia. The patient underwent an elective abortion at 18 weeks of gestation. Clinical abnormalities vanished completely within 3 months after the elective abortion, which provided additional evidence that proteinuria and hypertension were caused purely by pregnancy. In general, the term preeclampsia refers to new onset of hypertension and proteinuria after 20 weeks of gestation. When proteinuria or hypertension is newly observed before 20 weeks of gestation, they are practically associated with triploidy, trophoblastic disease, or antiphospholipid syndrome. However, our case was not associated with them. Therefore, we called this case "pure" preeclampsia. We confirm the notion for the first time that preeclampsia associated with glomerular capillary endotheliosis can occur before 20 weeks of gestation. In addition, this report describes the earliest onset of preeclampsia compared with previously published reports. We also discuss causes of preeclampsia in early gestation and refer to the issue of the application of renal biopsies during pregnancy.

Acute renal failure in pregnancy

OBJECTIVES

To provide an evidence-based, up-to-date review of the literature regarding the assessment and management of acute renal failure that may affect women during pregnancy and the postpartum period.

DESIGN

A review of the current literature was performed.

RESULTS

Acute renal failure is a rare complication of pregnancy but is associated with significant morbidity and mortality. Management requires knowledge of the renal physiologic changes occurring in pregnancy and the relevant diagnoses, both pregnancy-specific and those that may coincidentally occur with pregnancy. In addition, fetal effects must be taken into consideration.

CONCLUSIONS

Ideal care for women with acute renal failure in pregnancy or postpartum requires a multidisciplinary approach that may include maternal-fetal medicine, critical care medicine, nephrology, and neonatology specialists.

Postpartum Preeclampsia Management With Furosemide: A Randomized Clinical Trial

OBJECTIVE

This investigation was undertaken to estimate whether a brief postpartum course of furosemide for patients with preeclampsia benefits recovery and shortens hospitalization by enhancing diuresis, lessening severe hypertension, and reducing the need for antihypertensive therapy.

METHODS

Two hundred sixty-four patients with preeclampsia were enrolled. After spontaneous onset of postpartum diuresis and discontinuation of intravenous magnesium sulfate, patients were randomly assigned to receive either no therapy or 20 mg oral furosemide daily for 5 days with oral potassium supplementation. Patient outcomes were compared between treatment groups with regard to classification of hypertensive disease.

RESULTS

Only postpartum patients with severe preeclampsia (n = 70) who received furosemide compared with controls had significantly lower systolic blood pressure by postpartum day 2 (142 +/- 13 mm Hg compared with 153 +/- 19 mm Hg, P < .004) and required less antihypertensive therapy during hospitalization (14% compared with 26%, P = .371) and at discharge (6% compared with 26%, P = .045). No benefit was shown for patients with mild preeclampsia (n = 169) or superimposed preeclampsia (n = 25). Neither length of hospitalization nor frequency of delayed postpartum complications was positively affected by the intervention.

CONCLUSION

Brief postpartum furosemide therapy for patients with severe preeclampsia seems to enhance recovery by normalizing blood pressure more rapidly and reducing the need for antihypertensive therapy. Shortening of hospitalization and reduction of delayed postpartum complications were not benefitted.