Nifedipine treatment in preeclampsia reverts the increased erythrocyte aggregation to normal

Investigating the blood rheology in the first trimester pregnancies with high risk for preeclampsia

BACKGROUND

Pregnancy is a dynamic process associated with changes in vascular and rheological resistance. Maternal maladaptation to these changes is the leading cause of pregnancy complications such as preeclampsia.

OBJECTIVE

This study aimed to assess the hemorheological alterations in pregnancies with a high risk for preeclampsia in the first trimester.

METHODS

Ninety-two pregnant women were allocated into the high preeclampsia risk group (37 cases) and control groups (55 cases). Plasma and whole blood viscosity and red blood cell morphodynamic properties, including deformability and aggregation were assessed by Brookfield viscometer and laser-assisted optical rotational cell analyzer (LORRCA) at 11-14 gestational weeks.

RESULTS

Whole blood viscosity was significantly higher in the high-risk group at all shear rates. Plasma viscosity and hematologic factors showed no differences between the groups. Hematocrit levels positively correlated with high blood viscosity only in the high-risk group. There were no significant changes in the other deformability and aggregation parameters.

CONCLUSIONS

Changes in the whole blood viscosity of pregnant women with high preeclampsia risk refer to impaired microcirculation beginning from the early weeks of gestation. We suggest that the whole blood viscosity is consistent with the preeclampsia risk assessment in the first trimester, and its measurement might be promising for identifying high-preeclampsia-risk pregnancies.

Peripartum Investigation of Red Blood Cell Properties in Women Diagnosed with Early-Onset Preeclampsia

We investigated peripartum maternal red blood cell (RBC) properties in early-onset preeclampsia (PE). Repeated blood samples were taken prospectively for hemorheological measurements at PE diagnosis (n = 13) or during 26-34 weeks of gestation in healthy pregnancies (n = 24), then at delivery, and 72 h postpartum. RBC aggregation was characterized by M index (infrared light transmission between the aggregated RBCs in stasis) and aggregation index (AI-laser backscattering from the RBC aggregates). We observed significantly elevated RBC aggregation (M index = 9.8 vs. 8.5; AI = 72.9% vs. 67.5%; p < 0.001) and reduced RBC deformability in PE (p < 0.05). A positive linear relationship was observed between AI and gestational age at birth in PE by regression analysis (R² = 0.554; p = 0.006). ROC analysis of AI showed an AUC of 0.84 (0.68-0.99) (p = 0.001) for PE and indicated a cutoff of 69.4% (sensitivity = 83.3%; specificity = 62.5%), while M values showed an AUC of 0.75 (0.58-0.92) (p = 0.019) and indicated a cutoff of 8.39 (sensitivity = 90.9% and specificity = 50%). The predicted probabilities from the combination of AI and M variables showed increased AUC = 0.90 (0.79-1.00) (p < 0.001). Our results established impaired microcirculation in early-onset PE manifesting as deteriorated maternal RBC properties. The longer the pathologic pregnancy persists, the more pronounced the maternal erythrocyte aggregation. AI and M index could help in the prognostication of early-onset PE, but further investigations are warranted to confirm the prognostic role before the onset of symptoms.

Calcium channel blockers in the management of preterm labor and hypertension in pregnancy

Calcium channel blockers (CCBs) have the ability to inhibit contractility in smooth muscle cells. CCBs have an already established role in the treatment of non-pregnant hypertension and angina pectoris. Some epidemiological studies found an association between the use of CCBs and an increase in cardiovascular mortality, malignancy, and gastrointestinal bleeding. More recent studies with many more patients and a longer follow-up did not find these associations. In obstetrics CCBs have become increasingly popular for the management of preterm labor and pregnancy-induced hypertensive disorders. Meta-analysis shows that use of nifedipine in comparison with betamimetics is associated with a more frequent successful prolongation of pregnancy in case of preterm labor, resulting in significantly fewer admissions of newborns to the neonatal intensive care unit (NICU), and is associated with a lower incidence of respiratory distress syndrome. No adverse fetal side effects in humans have been reported with the use of nifedipine for obstetric indications. Nifedipine is an effective and safe drug to use when tocolytic therapy is indicated for preterm labor. In preeclampsia nifedipine effectively lowers blood pressure and can be a good alternative for (di) hydralazine.

Nifedipine or prazosin as a second agent to control early severe hypertension in pregnancy: a randomised controlled trial

OBJECTIVE

To determine whether nifedipine or prazosin is the more appropriate second-line antihypertensive agent in pregnancy.

DESIGN

Randomised controlled trial.

SETTING

Tygerberg Hospital, a tertiary referral centre.

POPULATION

Women with early, severe pre-eclampsia or hypertension in pregnancy, whose blood pressure could not be adequately controlled by methyldopa 2 g/day, but were otherwise stable.

METHODS

Nifedipine or prazosin were given and increased as necessary in a stepwise fashion. Once the maximum dose was reached, the other drug was added in a crossover pattern. Failure to control blood pressure, or the onset of maternal/fetal complications were indications for delivery. Patients reaching a minimum gestation of 34 weeks without complications were delivered electively.

MAIN OUTCOME MEASURES

Antenatal days gained; major maternal complications and perinatal survival.

RESULTS

Days gained on the second antihypertensive agent did not differ significantly (P = 0.9), while more days were gained using nifedipine as the crossover 'third agent' (P = 0.01). In the nifedipine group better renal function was recorded, but more cases with isolated low platelet counts occurred. More cases of pulmonary oedema as well as more nonviable mid-trimester and third trimester intrauterine deaths occurred in the prazosin group.

CONCLUSION

Nifedipine and prazosin as second agents allowed comparable amounts of time to be gained, although this changed when used as crossover third-line agents. The efficacy and safety of nifedipine in this study are consistent with the results of other studies. A greater number of intrauterine deaths occurred in the prazosin group.

Digital ischemia and gangrene due to red blood cell aggregation induced by acquired dysfibrinogenemia

Digital gangrene was observed in a patient who had angiographic findings of digital arterial occlusion. The patient's blood showed a marked red blood cell aggregation with rouleaux formation in long chains, which could not be dispersed at shear rates up to 200 sec-1. Studies of the patient's blood revealed the presence of an abnormal fibrinogen capable of aggregating normal red blood cells. This fibrinogen was found by Raman spectroscopy to have an increased alpha-helical content, whereas the beta-sheet content was decreased. Defibrinogenation therapy with ancrod resulted in a dramatic symptomatic relief. The disappearance of the abnormal fibrinogen 6 months later and an absence of a family history indicate that this dysfibrinogenemia was acquired.

Drug management of hypertensive disorders of pregnancy

Drugs used in the acute and long-term management of hypertension in pregnancy and the preeclampsia-eclampsia syndrome have been reviewed and their therapeutic effects and maternal and fetal adverse effects have been considered. The review also focuses on recent developments in the areas of prevention and management of pre-eclampsia-eclampsia syndrome. Although a number of new drugs have emerged, as potentially useful in the management of hypertension in pregnancy and pre-eclampsia-eclampsia syndrome, some remain at the cornerstone of therapy; for example, methyldopa for long-term treatment of chronic hypertension, hydralazine or nifedipine for rapid reduction of severely elevated blood pressure, and magnesium sulphate for eclampsia. Some of these agents, especially the calcium antagonists, show promise in that their use is associated with fewer side effects. Safety for the fetus, however, has not been adequately evaluated yet. Neither aspirin nor calcium supplements appear to improve the outcome in pregnancy. Currently, the dilemma whether to treat hypertension in pregnancy and pre-eclampsia-eclampsia syndrome with old, established, cost-effective drugs or the promising newer drugs provides an interesting academic challenge.

Labetalol vs. methyldopa in the treatment of pregnancy-induced hypertension

OBJECTIVE

To assess the efficacy and safety of labetalol compared with methyldopa in the management of mild and moderate cases of pregnancy-induced hypertension (PIH).

METHODS

One hundred four primigravidas with PIH were randomly allocated to receive either labetalol (group A) or methyldopa (group B). The dose of the drugs was doubled every 48 h to maintain a mean arterial blood pressure < or = 103.6 mmHg. Clinico-biochemical effects and frequency of side effects were studied. The statistical level of significance was taken at P < 0.05.

RESULTS

Ten patients in group B (18.5%) developed significant proteinuria (> 30 mg/dl) whereas none developed proteinuria in group A. Labetalol was quicker and more efficient at controlling blood pressure, having a beneficial effect on renal functions and causing fewer side effects compared with methyldopa. The rate of induction of labor and rate of cesarean section for uncontrolled PIH was less in group A (48% and 1%, respectively) compared with group B (63.0% and 5.6%, respectively). Moreover a higher Bishop score at induction of labor was noticed in group A.

CONCLUSIONS

Labetalol is better tolerated than methyldopa, gives more efficient control of blood pressure and may have a ripening effect on the uterine cervix.