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Cardiovascular DiseasesNCT00005208

Regulation of Placental Vascular Reactivity in Pregnancy-induced Hypertension

An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

To elucidate the role of an imbalance in vasodilator prostacyclin (PGI2) and vasoconstrictor thromboxane (TxA2) in pregnancy-induced hypertension Read more about this study

Who is it for?
Ages Up to 100 years, men only
How many people
Not given
Where
No sites listed yet
Study dates
Sep 1987to Jul 1992
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages Up to 100 years
  • Men only
  • No healthy volunteers
  • Child, Adult, Older adult

No eligibility criteria

About this study

To elucidate the role of an imbalance in vasodilator prostacyclin (PGI2) and vasoconstrictor thromboxane (TxA2) in pregnancy-induced hypertension

Read the detailed description

BACKGROUND:

Pregnancy-induced hypertension (PIH) is associated with increased fetal and neonatal morbidity and mortality possibly resulting from hypoxia in utero. The primary pathology of PIH involves a reduction in uteroplacental blood flow but modern imaging techniques have now shown that increased impedance of the fetal-placental circulation and hence reduced blood flow can also be found in PIH. This may represent a direct effect of hypoxia or be a fetal adaptation to increase placental oxygen extraction to relieve hypoxia. The fetal-placental circulation is regulated by humoral agents and vascular pressure. An imbalance of vasodilator prostacyclin (PGI2) and vasoconstrictor thromboxane (TxA2) production is reported to underlie the vasoconstriction seen in PIH.

The study resulted from the 1986 release of a Request for Applications for Research on Hypertension in Pregnancy by the National Heart, Lung, and Blood Institute and the National Institute of Child Health and Human Development.

DESIGN NARRATIVE:

The fetal-placental circulations of perfused human placental cotyledons from normotensive and pregnancy-induced hypertensive pregnancies were used to determine if an imbalance in PGI2/TxA2 production existed and its relationship to the responses of the fetal-placental circulation to vasoconstriction. Studies were also conducted on the effects of hypocalcemia and hypomagnesemia, hypoxia, and drugs.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Medical subject headings
Cardiovascular Diseases, Heart Diseases, Hypertension, Pre-Eclampsia

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted26 May 2000 (estimated)
  2. Study startSep 1987
  3. Study completionJul 1992

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
IDs, dates and publications
ClinicalTrials.gov ID
NCT00005208
Sponsor's protocol ID
1087
Other IDs
R01HL040029
Status last verified
May 2000
First submitted
25 May 2000
Last updated
29 Feb 2016
Results posted
No

Publications

  • Myatt L, Brewer AS, Brockman DE. The comparative effects of big endothelin-1, endothelin-1, and endothelin-3 in the human fetal-placental circulation. Am J Obstet Gynecol. 1992 Dec;167(6):1651-6. doi: 10.1016/0002-9378(92)91756-z.

    PubMed 1471681
  • Myatt L. Control of vascular resistance in the human placenta. Placenta. 1992 Jul-Aug;13(4):329-41. doi: 10.1016/0143-4004(92)90057-z. No abstract available.

    PubMed 1438081
  • Eis AW, Mitchell MD, Myatt L. Endothelin transfer and endothelin effects on water transfer in human fetal membranes. Obstet Gynecol. 1992 Mar;79(3):411-5. doi: 10.1097/00006250-199203000-00017.

    PubMed 1738524
  • Myatt L, Brewer AS, Langdon G, Brockman DE. Attenuation of the vasoconstrictor effects of thromboxane and endothelin by nitric oxide in the human fetal-placental circulation. Am J Obstet Gynecol. 1992 Jan;166(1 Pt 1):224-30. doi: 10.1016/0002-9378(92)91863-6.

    PubMed 1733199
  • Myatt L, Langdon G, Brewer AS, Brockman DE. Endothelin-1-induced vasoconstriction is not mediated by thromboxane release and action in the human fetal-placental circulation. Am J Obstet Gynecol. 1991 Dec;165(6 Pt 1):1717-22. doi: 10.1016/0002-9378(91)90021-i.

    PubMed 1750466
  • Jacobson RL, Brewer A, Eis A, Siddiqi TA, Myatt L. Transfer of aspirin across the perfused human placental cotyledon. Am J Obstet Gynecol. 1991 Oct;165(4 Pt 1):939-44. doi: 10.1016/0002-9378(91)90444-v.

    PubMed 1951559
  • Myatt L, Brewer A, Brockman DE. The action of nitric oxide in the perfused human fetal-placental circulation. Am J Obstet Gynecol. 1991 Feb;164(2):687-92. doi: 10.1016/s0002-9378(11)80047-5.

    PubMed 1899534
  • Myatt L, Brockman DE, Langdon G, Pollock JS. Constitutive calcium-dependent isoform of nitric oxide synthase in the human placental villous vascular tree. Placenta. 1993 Jul-Aug;14(4):373-83. doi: 10.1016/s0143-4004(05)80459-x.

    PubMed 7504255

Questions about this trial

What is this clinical trial studying?

An observational study of Cardiovascular Diseases and Heart Diseases, run by National Heart, Lung, and Blood Institute (NHLBI).

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 29 Feb 2016. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00005208, which also lists 8 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Feb 2016.

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