Clinical Trial: Treatment of Orthostatic Hypotension in Autonomic Failure

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Evaluation and Treatment of Autonomic Failure.

Brief Summary: The autonomic nervous system serves multiple regulatory functions in the body, including the regulation of blood pressure and heart rate, gut motility, sweating and sexual function. There are several diseases characterized by abnormal function of the autonomic nervous system. Medications can also alter autonomic function. Impairment of the autonomic nervous system by diseases or drugs may lead to several symptoms, including blood pressure problems (e.g., high blood pressure lying down and low blood pressure on standing), sweating abnormalities, constipation or diarrhea and sexual dysfunction. Because treatment options for these patients are limited. We propose to study patients autonomic failure and low blood pressure upon standing and determine the cause of their disease by history and examination and their response to autonomic testing which have already been standardized in our laboratory. Based on their possible cause, we will tests different medications that may alleviate their symptoms.

Detailed Summary:

Subjects will be admitted to the Clinical Research Center at Vanderbilt University for the studies. The average inpatient stay is 7 days. Initially a complete history and physical will be performed and the patient will be placed on a low monamine, no methylxanthine, 150 mEq sodium, 60-80 mEq potassium diet.

The following tests will be performed:

  1. Meal challenge:

    We observed profound effects of diet on blood pressure in many patients with orthostatic hypotension. Some patients dropped their blood pressure by 40-60 mmHg during the postprandial period. Blood pressure will be monitored with an automated device (Dinamap) after feeding the patients with a standardized diet.

  2. Physiologic autonomic tests:

    Patients are studied supine, and blood pressure is monitored with a sphygmomanometer or an automated device (Dinamap, Finapres or tonometer).

    1. Orthostatic test: Blood pressure and heart rate are measured in the supine and standing positions. Orthostatic hypotension without an adequate heart rate increase is indicative of autonomic failure. On the other hand, orthostatic tachycardia in the absence of volume depletion is seen in "hyperadrenergic orthostatic hypotension".
    2. Standing time: The time the patient can stand motionless gives a very good indication of functional capacity.
    3. Deep breathing: Heart rate is monitored with an ECG and the patient is asked to breathe deeply 6 times each minute for two minutes. Heart
      Sponsor: Vanderbilt University

      Current Primary Outcome: Increase in seated systolic blood pressure 1-hr post drug compared to baseline. [ Time Frame: 1.5-4 hours ]

      Original Primary Outcome: Increase in seated systolic blood pressure 1-hr post drug compared to baseline.

      Current Secondary Outcome: Increase in standing time 1-hr post drug compared to baseline [ Time Frame: 1.5-4 hours ]

      Original Secondary Outcome: Increase in standing time 1-hr post drug compared to baseline

      Information By: Vanderbilt University Medical Center

      Dates:
      Date Received: September 14, 2005
      Date Started: March 2002
      Date Completion:
      Last Updated: January 16, 2017
      Last Verified: January 2017