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.
The purpose of this research study is to find out if smoking cessation combined with sildenafil, an FDA approved drug for pulmonary hypertension, will decrease inflammation in the lung. Even if a smoker stops smoking, the harmful effects caused by previous smoking may recruit inflammatory cells to those affected areas, leading to lung injury. In about 30-40% of smokers, this inflammation combined with irregular blood flow in the lungs may lead to emphysema. The study goal is to measure and compare individual responses to smoking cessation, Sildenafil and placebo used three times per day, and imaging of the lungs using non-contrast and contrast CT scans to see if there is a possible decrease of inflammation and an increase of blood flow in the lungs. The study also intends to see if using Sildenafil three times per day, in addition to smoking cessation will restore blood flow to the possible injured areas of the lungs. Sildenafil is an FDA approved medication for pulmonary hypertension but will be used off-label to study the effects it may or may not have on the blood flow in possible injured areas of the lungs. Non-smokers will be enrolled to compare lung imaging and the effects of Sildenafil on their lungs with that of smokers undergoing a smoking cessation program with placebo or Sildenafil. Non-smokers will complete identical measurements as smokers, with Sildenafil used three times per day or no medication across a similar 90 day period of time. Vascular measurements of pulse wave velocity, carotid artery compliance/stiffness and pressure wave reflection will be done at baseline and 90 day visits.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
162
Sildenafil, 20mg three times daily for 3 month period.
Placebo manufactured to look like Sildenafil 20 MG
Vascular pulse measurement at the radial, brachial, femoral, and carotid arteries are taken using a tonometer probe.
University of Iowa Hospitals and Clinics
Iowa City, Iowa, United States
Measure and compare individual smokers' responses to smoking cessation, Sildenafil and placebo with lung imaging to determine decrease of inflammation and increase of blood flow in lungs.
Our outcome measure is the change in regional blood volume between baseline and interventions with CT imaging, sildenafil/placebo and smoking cessation.
Time frame: 90 Days
Pulse wave velocity of carotid radial, brachial, femoral and carotid arteries
Our outcome measure is the difference of arterial stiffness between baseline and 90 day visits.
Time frame: Baseline and 90 day
Carotid beta-stiffness index
Our outcome measure is the difference of common carotid artery stiffness between baseline and 90 day visits
Time frame: Baseline and 90 Day
Carotid augmentation index
Our outcome measure is the difference of pressure wave reflection between baseline and 90 day visits
Time frame: Baseline and 90 Day
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An echocardiogram is done by using a probe placed on the skin.
Carotid pulse measurement taken using a tonometer probe