Imaging Study of the Lungs During an Allergic Asthma Attack

This study has been completed.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Robert Scott Harris, M.D., Massachusetts General Hospital
ClinicalTrials.gov Identifier:
NCT01547286
First received: February 15, 2012
Last updated: October 25, 2013
Last verified: October 2013

February 15, 2012
October 25, 2013
May 2012
October 2013   (final data collection date for primary outcome measure)
  • mean-normalized perfusion within ventilation defective regions versus outside [ Time Frame: 3 hours after allergen administration ] [ Designated as safety issue: No ]
    Blood flow compared to the mean blood flow of the lung (mean normalized perfusion) inside areas that have reduced ventilation (Vdefs) compared to outside the Vdefs.
  • mean-normalized perfusion within ventilation defective regions versus outside [ Time Frame: 7 hours after allergen administration ] [ Designated as safety issue: No ]
    Blood flow compared to the mean blood flow of the lung (mean normalized perfusion) inside areas that have reduced ventilation (Vdefs) compared to outside the Vdefs.
Same as current
Complete list of historical versions of study NCT01547286 on ClinicalTrials.gov Archive Site
  • COV Squared of Perfusion [ Time Frame: 3 hours after allergen administration ] [ Designated as safety issue: No ]
    Coefficient of variation squared of the perfusion in the imaged lung. This measures the overall heterogeneity of perfusion in the imaged lung.
  • COV Squared of Perfusion [ Time Frame: 7 hours after allergen administration ] [ Designated as safety issue: No ]
    Coefficient of variation squared of the perfusion in the imaged lung. This measures the overall heterogeneity of perfusion in the imaged lung.
Same as current
Not Provided
Not Provided
 
Imaging Study of the Lungs During an Allergic Asthma Attack
Redistribution of Pulmonary Perfusion During Bronchoconstriction in Asthma

Asthma is a disease of rapidly increasing incidence that already affects more than 17 million people in the United States alone. It has long been known that areas of severely reduced airflow occur in asthma and contribute significantly to the impairment of gas exchange in this disease. However, the extent to which local blood flow changes during an asthmatic attack is unclear. The purpose of this study is using PET-CT imaging to evaluate how the blood flow changes in the lungs during an asthma attack induced by allergens.

Asthma is a disease of rapidly increasing incidence that already affects more than 17 million people in the United States alone. It is of major importance to understand the mechanisms responsible for underlying mechanical and physiological changes that occur during asthma exacerbations. The effect of asthma on the pulmonary vasculature is virtually unknown. It has long been known that areas of severely reduced airflow occur in asthma and contribute significantly to the impairment of gas exchange in this disease. However, the extent to which local blood flow changes during an asthmatic attack is unclear. This proposal is designed to evaluate the relevance of potential mechanisms responsible for the blood flow defects seen in our PET studies of subjects with asthma and identify factors modifying that perfusion distribution. With this knowledge, it is hoped that a more focused basic research is motivated to understand the fundamental mechanisms behind these processes ultimately targeted to improved asthma therapy. Comparing these measures in healthy subjects and asthmatics patients may lead to methods to improve patient care.

Interventional
Not Provided
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Basic Science
  • Asthma
  • Atopy
  • Biological: Standardized Cat Allergen Extract and Standardized Dust Mite Allergen
    The route of administration will be topical application of the titrated allergen via nebulized droplets to the lungs. The starting dose of allergen will be 3 dose dilutions below the estimated PC20-allergen delivered for 5 minutes at tidal breathing, followed by FEV1 at 10-minute intervals until the lowest FEV1 is established. If the %FEV1 fall is < 20%, the next concentration is given, until the FEV1 falls ≥ 20%. When this happens the FEV1 will be followed at 10, 20, 30, 45, and 60 minutes, then hourly for 7 hours. The early asthmatic response is the maximum %FEV1 fall between 0 and 3 hours and the late asthmatic response between 3 and 7 hours post allergen challenge.
    Other Names:
    • •Reagents from Greer will be used:
    • •Standardized Cat Hair Extract
    • •Standardized mite extract-Dermatophagoides farinae
    • •Standardized mite extract-Dermatophagoides pteronyssinus
  • Radiation: CT imaging, functional PET imaging
    Physiology study using CT and PET imaging with Nitrogen-13 (13NN) saline as radiotracer; images obtained during the early and late phases after allergen challenge
  • Drug: Nebulized methacholine inhalation
    Standard methacholine challenge performed once to determine the subject's PC20 dose (the dose that causes a 20% fall in FEV1 from baseline).
    Other Name: MethaPharm Provocholine
Experimental: Allergic asthmatic
Interventions:
  • Biological: Standardized Cat Allergen Extract and Standardized Dust Mite Allergen
  • Radiation: CT imaging, functional PET imaging
  • Drug: Nebulized methacholine inhalation
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
5
October 2013
October 2013   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Mild asthma is defined in the National Institutes of Health 2002 guidelines for the Diagnosis and Management of Asthma. Briefly, people with mild asthma are defined as those with symptoms greater than 2 times a week but less than once per day with normal FEV1(> 80% predicted)
  • Clinical history of allergic symptoms to cat or dust mite allergen and demonstrated skin reactivity
  • Life-long absence of cigarette smoking (defined as a lifetime total of less than 5 pack-years); none in 5 years
  • Willing and able to give informed consent
  • Expressed the desire to participate in an interview with the principal investigator

Exclusion Criteria:

  • Women of childbearing potential who are documented to be pregnant (based on serum beta-HCG testing) or who are nursing.
  • The presence of spontaneous asthmatic episode or clinical evidence of upper respiratory tract infection within the previous 6 weeks.
  • Participation in research study involving a drug or biologic during the 30 days prior to the study.
  • Intolerance to albuterol, atropine, or lidocaine.
  • Antihistamines within 7 days of the screening visit.
  • Known exposure to agents that are associated with pulmonary disease (i.e. asbestos, silica).
  • Presence of other known pulmonary disease, coronary disease, congestive heart failure, ventricular arrhythmias, history of a cerebrovascular accident, renal failure (or creatinine > 1.5, if known), history of anaphylaxis, cirrhosis or presence of a significant disease, which in the opinion of the principal investigator, would pose a significant risk for the subject or confound the results of the study.
  • Use of systemic steroids, increased use of inhaled steroids, beta blockers and MAO inhibitors or a visit for an asthma exacerbation within

    1 month of the screening visit.

  • A history of asthma-related respiratory failure requiring intubation.
  • A history of hospitalization for asthma.
  • Subjects with a high possibility of poor compliance with the study as judged by the principal investigator.
  • History of contrast dye allergy.
  • Unresponsive to bronchodilator agents.
  • Quantitative skin prick test at or below a dilution level of standardized cat allergen extract of 1:2048 (4.88 BAU/ml)for subjects being challenged with cat allergen.
  • Quantitative skin prick test at or below a dilution level of standardized mite allergen extract of 1:2048 (4.88 BAU/ml)for subjects being challenged with either mite allergen.
  • Subjects who, by participating in one of these studies, will have a cumulative radiation dose exceeding the maximum yearly recommended dose for a research subject (50 mSv).
  • Previous participation in one of the protocols in this proposal.
  • Contraindication to methacholine challenge testing (FEV1 < 50% predicted or < 1L, heart attack or stroke in last 3 months, uncontrolled hypertension, or known aortic aneurysm).
  • Body Mass Index (BMI ) > 32
Both
18 Years to 65 Years
No
Contact information is only displayed when the study is recruiting subjects
United States
 
NCT01547286
2007P002386, 1R01HL086717-01A2
Yes
Robert Scott Harris, M.D., Massachusetts General Hospital
Massachusetts General Hospital
National Heart, Lung, and Blood Institute (NHLBI)
Principal Investigator: R. Scott Harris, MD Massachusetts General Hospital
Massachusetts General Hospital
October 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP