The Role of Endothelin in the Supine Hypertension of Autonomic Failure
調査の概要
詳細な説明
The pathophysiologic mechanisms causing supine hypertension in patients with autonomic failure are not completely understood.In MSA patients, supine hypertension may be explained by residual sympathetic tone, possibly acting on hypersensitive adrenoreceptors and unstrained by the lack of baroreflex modulation. In contrast, the pathogenesis of hypertension in PAF remains unknown. Hypertension in these patients is not related to intravascular volume, residual sympathetic tone, or renin mechanisms. Increased vascular resistance is the underlying hemodynamic mechanism. The driving force of this increased vascular tone, however, is not known.
We hypothesize that endothelin (ET)-l contributes to the increased vascular resistance in pure autonomic failure patients with supine hypertension. To gauge its contribution to blood pressure regulation, we will induce endothelin blockade with acute systemic administration of BQ123 in an ascending dose regimen (25, 50, 100 and 300 nmol/min) and we will compare the hemodynamic effects between PAF and MSA patients.
Subjects will be studied on 3 different days, one with saline (placebo) and two with BQ123: a 'low dose' day (25 and 50 nmol/min infusions separated by 75 min) and a 'high dose' day (100 and 300 nmol/min infusions separated by 75 min). The order of the placebo day will be randomized in a single-blinded manner so that each subject receives it on a different visit. The order of the BQ123 study days will be always the same, starting with the low dose. If SBP drops by >40 mm Hg or SBP < 130 mm Hg during the monitoring period after the first or second infusion, the following dose(s) of BQ123 will not be given and patients will receive normal saline until the study ends.
Ganglionic Blockade with Trimethaphan (optional study day):
The purpose of this study day is to determine the level of residual sympathetic tone that contributes to supine hypertension in each autonomic failure patient by inducing transient withdrawal of the autonomic nervous system. This approach would allow us to identify patients in whom supine hypertension is not driven by sympathetic tone and thus, better characterize the role of endothelin in the hypertension of these patients.
研究の種類
段階
- フェーズ 1
連絡先と場所
研究場所
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Tennessee
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Nashville、Tennessee、アメリカ、37232
- Vanderbilt University
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参加基準
適格基準
就学可能な年齢
健康ボランティアの受け入れ
受講資格のある性別
説明
Inclusion Criteria:
- Patients with autonomic failure and supine hypertension from all races, who are in the hospital participating in the study "The Evaluation and Treatment of Autonomic Failure" (IRB# 000814).
- Supine hypertension, defined as a systolic blood pressure >150 mm Hg or diastolic blood pressure > 90 mm Hg.
- Males and females, between 18-85yr.
- Provide written informed consent to participate in the study and understand that they may withdraw their consent at any time without prejudice to their future medical care.
Exclusion Criteria:
- Pregnant women.
- High-risk patients (e.g. heart failure, symptomatic coronary artery disease, liver impairment, history of stroke or myocardial infarction).
- History of serious allergies or asthma.
- In the investigator's opinion, have clinically significant abnormalities on clinical, mental examination or laboratory testing.
- All medical students.
研究計画
研究はどのように設計されていますか?
デザインの詳細
- 主な目的:他の
- 割り当て:ランダム化
- 介入モデル:クロスオーバー割り当て
- マスキング:独身
武器と介入
参加者グループ / アーム |
介入・治療 |
---|---|
実験的:BQ123
endothelin blocker
|
Low dose day: 25 nmol/min, single IV infusion for 15 min.
他の名前:
Low dose day: 50 nmol/min, single IV infusion for 15 min
他の名前:
High dose day: 300 nmol/min, single IV infusion for 15 min.
他の名前:
|
プラセボコンパレーター:Saline
IV saline
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2-3 IV saline infusions for 15 min each.
他の名前:
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この研究は何を測定していますか?
主要な結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
---|---|---|
Change in Systolic BP
時間枠:0 -4 hr post infusion
|
Change from baseline in systolic blood pressure
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0 -4 hr post infusion
|
二次結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
---|---|---|
Change in cardiac output, stroke volume and systemic vascular resistance
時間枠:0-4 hr post infusion
|
Percent change from baseline in hemodynamic parameters
|
0-4 hr post infusion
|
協力者と研究者
スポンサー
研究記録日
主要日程の研究
研究開始 (実際)
一次修了 (実際)
研究の完了 (実際)
試験登録日
最初に提出
QC基準を満たした最初の提出物
最初の投稿 (見積もり)
学習記録の更新
投稿された最後の更新 (実際)
QC基準を満たした最後の更新が送信されました
最終確認日
詳しくは
本研究に関する用語
キーワード
追加の関連 MeSH 用語
その他の研究ID番号
- 091344
個々の参加者データ (IPD) の計画
個々の参加者データ (IPD) を共有する予定はありますか?
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BQ123の臨床試験
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University of Southern DenmarkThe University of Texas at Arlington積極的、募集していない
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Cambridge University Hospitals NHS Foundation TrustGlaxoSmithKline完了