Functional CT Assessment of Pulmonary Arterial Dysfunction in Smoking Associated Emphysema

Emphysema Clinical Trial

Official title:

Functional CT Assessment of Pulmonary Arterial Dysfunction in Smoking Associated Emphysema

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT02682147
• Other study ID #: 201508782
• Secondary ID: R01HL130883
• Status: Recruiting
• Phase: Phase 4
• Start date: July 10, 2017
• Est. completion date: December 2024

Study information

• Verified date: March 2024
• Source: University of Iowa
• Contact: Debra J OConnell Moore, MBA
• Phone: 319-356-1693
• Email: debra-oconnell-moore[@]uiowa.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This study will use dual energy x-ray computed tomography (DECT) to evaluate the relationship between heterogeneous perfusion, hypoxia (low oxygen in inspired gas) and induction of pulmonary vascular dilatation to characterize emphysema susceptibility in a normal smoking population. The investigators will correlate DECT measures of perfusion with lung injury measured by single photon emission computed tomography (SPECT). The investigators will study the effect of pulmonary arterial vasodilation to see if it eliminates indices of persistent lung injury in smokers that are susceptible to emphysema

Description:

Imaging-based metrics have recently played a central role in the quest to identify chronic obstructive pulmonary disease (COPD) phenotypes, serving to establish homogeneous sub-populations to aid in genotyping, therapeutic targeting and design and outcomes assessment. Recent findings in both animals and humans have lead us to believe that CT derived perfusion (PBF) and mean transit time (MTT) measures within regionally injured lung parenchyma provide for a functional phenotype of which may be directly tied to the etiology of the pathologic process leading to emphysema in acentrilobular emphysema susceptible subset of the smoking population. The primary hypotheses of the proposal are built around the notion that smokers prone to emphysema have abnormal vasoregulation in that regional hypoxic pulmonary vasoconstriction (HPV) continues despite regional lung injury. This failure to block vasoconstriction alters the repair response and leads to tissue destruction in emphysema susceptible smokers (SS) with abnormal vasoregulation. The normal response to regional hypoxia is to shunt blood towards better-ventilated regions. However, smoking induces small scale, regional infiltrates which in turn lead to local hypoxia, HPV would interfere with defense mechanisms serving to clear the irritant and thus interfere with mechanisms of repair. The investigators have demonstrated that, in SS subjects with normal PFTs but CT evidence of early centriacinar emphysema (CAE), there is an increased heterogeneity of perfusion. This is supportive of the notion that attenuation of vasoconstriction has failed. Further, the investigators have demonstrated a tight correlation between quantitative CT evidence of emphysema with reduced lung volume (LV) filling down to very small amounts of emphysema.

The investigators outline a series of experiments seeking to:

1. link increased pulmonary perfusion heterogeneity in SS subjects to the lung's response to alveolar oxygenation;

2. establish that the perfusion heterogeneity is reversible;

3. demonstrate that the response to inflammation and not just inflammation itself is a key factor in the increased heterogeneity.

With any combination of positive outcomes of this study, the investigators will have provided new insights into disease etiology, serving to provide new targets for disease intervention and providing the tools needed for assessing outcomes.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 80
• Est. completion date: December 2024
• Est. primary completion date: December 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 25 Years to 65 Years

Eligibility

Inclusion Criteria:

1. Must be between the ages of 25 and 65.

2. Must be currently smoking at least 1/2 pack/day (confirmed with cotinine level).

3. Must have pulmonary function test (PFT) results that meet the following (there will be two groups):

Group 1:

• Forced expiratory volume at one second (FEV1)/Forced vital capacity (FVC) > 70%

• Forced Expiratory Flow at 25-75% of predicted(FEF25-75) > 79% of predicted

• FVC greater than 80% of predicted

Group 2:

For subjects with mild lung impairment:

• FEV1>80% of predicted

• FEV1/FVC<0.7

4. Must be able to give informed consent for self.

Exclusion Criteria:

1. Pregnant or breastfeeding females.

2. Body Mass Index (BMI) greater than 32.

3. Weight of greater than 220 pounds (100 kg).

4. Allergies to shell fish, seafood, eggs or iodine.

5. Heart disease, kidney disease or diabetes.

6. Diagnosis of asthma.

7. Usage of any medications that are known to affect the heart or lungs (contraceptives, anti-depressants, analgesics EXCEPT aspirin, antihypertensives, and medications for osteoporosis and gastrointestinal diseases will be allowed).

8. Any metal in or on the body between the nose and the abdomen.

9. Any major organ system disease (by judgment of study medical team).

10. A glomerular filtration rate of 60 cc per minute or less.

For the subjects that will receive Sildenafil as part of the study, additional exclusion criteria are as follows:

1. Nitroglycerin usage or nitrates (in addition to nitroglycerin) and use of phosphodiesterase 5 (PDE5) inhibitors within the previous 7 days of the study date.

2. Prior history of hypersensitivity to Sildenafil.

Related Conditions & MeSH terms

• Emphysema
• Pulmonary Emphysema

Intervention

Drug:
• Hypoxia administration study group
scan completed after 5 minutes of breathing in hypoxic air
• Hyperoxia administration study group
scan completed after up to 15 minutes of breathing in hyperoxic air
• Sildenafil
One dose of 20 mg Sildenafil will be given one hour before CT imaging.

Locations

Country	Name	City	State
United States	University of Iowa	Iowa City	Iowa

Sponsors (3)

Lead Sponsor	Collaborator
Eric A. Hoffman	National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH)

Country where clinical trial is conducted

United States, 

References & Publications (2)

Alford SK, van Beek EJ, McLennan G, Hoffman EA. Heterogeneity of pulmonary perfusion as a mechanistic image-based phenotype in emphysema susceptible smokers. Proc Natl Acad Sci U S A. 2010 Apr 20;107(16):7485-90. doi: 10.1073/pnas.0913880107. Epub 2010 Ap — View Citation

Iyer KS, Newell JD Jr, Jin D, Fuld MK, Saha PK, Hansdottir S, Hoffman EA. Quantitative Dual-Energy Computed Tomography Supports a Vascular Etiology of Smoking-induced Inflammatory Lung Disease. Am J Respir Crit Care Med. 2016 Mar 15;193(6):652-61. doi: 10 — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Perfused blood volume assessed pre and post sildenafil administration	Perfused blood volume will be measured by CT scan at two time points and compared at two points, pre and post the administration of sildenafil.	Pre sildenafil adminstration and one hour after sildenafil adminstration.
Primary	Perfused blood volume assessed pre and post hyperoxic breathing	Perfused blood volume will be measured by CT scan at two time points and compared at two points, pre and post hyperoxic breathing	Pre hyperoxic breathing and 15 minutes post hyperoxic breathing
Primary	Perfused blood volume assessed pre and post hypoxic breathing	Perfused blood volume will be measured by CT scan at two time points and compared at two points, pre and post hypoxic breathing	Pre hypoxic breathing and 15 minutes post hypoxic breathing