Assessment of the Changes in Cortical and Medullary Renal Blood Flow During Exercise in Healthy Subjects Using Contrast Enhanced Ultrasound
| Status: | Recruiting |
|---|---|
| Conditions: | Healthy Studies |
| Therapuetic Areas: | Other |
| Healthy: | No |
| Age Range: | 18 - 50 |
| Updated: | 4/21/2016 |
| Start Date: | January 2016 |
| End Date: | March 2017 |
| Contact: | Sharon F Johnson, BA |
| Email: | sfj8n@virginia.edu |
| Phone: | 4349823198 |
Renal parenchymal blood flow can be divided in cortical and medullary blood flow. Changes
and factors affecting renal medullary blood flow have not been studied in detail previously
as investigators/doctors did not have tools to monitor renal medullary blood flow in vivo.
Since Trueta first described renal medullary blood flow, multiple attempts have been made to
study renal medullary blood flow using invasive methods. Recently renal medullary blood flow
measurement using contrast US has emerged as a promising technique that investigators can
use to study renal medullary blood flow in vivo. In this study investigators are aiming to
study changes in renal parenchymal (cortical and medullary) blood flow with exercise in
healthy subject.
and factors affecting renal medullary blood flow have not been studied in detail previously
as investigators/doctors did not have tools to monitor renal medullary blood flow in vivo.
Since Trueta first described renal medullary blood flow, multiple attempts have been made to
study renal medullary blood flow using invasive methods. Recently renal medullary blood flow
measurement using contrast US has emerged as a promising technique that investigators can
use to study renal medullary blood flow in vivo. In this study investigators are aiming to
study changes in renal parenchymal (cortical and medullary) blood flow with exercise in
healthy subject.
This study requires a screening day and two visits on separate days to the Clinical Research
Unit (CRU). Three visits total.
Screening Visit:
1. The subjects will undergo detailed history and physical examination.
2. The inclusion and exclusion criteria will be reviewed.
3. The details of the study procedures, potential risks and benefits will be reviewed with
each subject and all potential questions will be answered.
4. Subjects' understating of all details of the study components will be ascertained and
they will be asked to sign the informed consent form.
5. A copy of the signed informed consent will be placed in study file and another copy
will be provided to each subject.
6. The study visit day will be scheduled within 2 weeks of the screening day.
7. All subjects will be asked to arrive on their first study day after an overnight fast.
They will be instructed to avoid caffeine and exercise for 24 hours.
Study Day #1 The subjects will arrive in the CRU in the morning. Subjects' understanding of
all study related procedures will be assessed and all remaining questions will be answered.
The following sequence of procedures will be followed for all enrolled subjects.
1. Physical exam including vital signs (Blood Pressure, Heart Rate, Weight, Height,
Respiration Rate, Temperature)
2. Urine pregnancy test for women of child bearing age. If positive, subjects will be
excluded.
Determination of peak oxygen consumption
3. Subjects will complete a continuous VO2 peak bicycle ergometer protocol.
1. Each subject will start peddling on a stationary bike
2. The initial power output (PO) will be set at 20 watts
3. The power output will be increased by 15 watts every 2-minutes until volitional
exhaustion.
4. Metabolic data will be collected during the protocol using standard open-circuit
spirometric techniques (Viasys Vmax Encore, Yorba Linda, CA)
5. Heart rate was assessed electrocardiographically.
6. VO2 peak will be chosen as the highest VO2 attained during the exercise protocol
On Day 2 of testing
1. Check Vitals (BP, HR, Wt., RR, Temp.)
2. Insert peripheral IV line Baseline renal blood flow measurement using contrast enhanced
ultrasonography
3. The Definity vial will be placed at room temperature before being used. It will be
activated after shaking the vial using Vialmax® for 45 seconds. It will be used
immediately after activation.
4. 0.4 ml of Definity will be mixed in 10 ml of preservative free saline.
5. Infusion of Definity into a peripheral vein will be started at 2 ml/min and titrated
for optimal image quality using a minipump (not to exceed 10 ml/min at any time).
6. Baseline contrast ultrasound imaging of right kidney will be performed with low
mechanical index (MI) of 0.2.
7. 4 - 5 ultrasound impulses with high MI of 1.0 and duration of 1 second will be used to
destruct the microbubbles in the kidney tissue
8. Ultrasound imaging of the kidney with low MI (0.2) will continue immediately after each
impulse for several seconds.
9. Infusion of Definity will stop at this point.
10. Vital signs will be monitored every 15 minutes and continuous pulse oximetry will be
performed during Definity administration.
11. Vital signs and pulse oximetry will be monitored every 15 minutes until 30 minutes
after discontinuation of Definity.
12. A urine dipstick will be performed by the study team 30 minutes after completion of
Definity infusion if a sample is available.
Constant load Exercise protocol
13. Subjects will complete 30 minutes of continuous cycling at the power output associated
with 85% of VO2peak from the continuous bicycle ergometer protocol. Metabolic data will
be collected as described above.
14. Once metabolic parameter are reached, exercise will be stopped and subject will be
asked to lie down on the bed Renal Blood flow measurement following exercise using
contrast enhanced ultrasonography
15. Immediately after completion of exercise protocol, steps 5 - 12 under day 2 procedures
will be repeated.
16. The study procedures will end at this point.
Unit (CRU). Three visits total.
Screening Visit:
1. The subjects will undergo detailed history and physical examination.
2. The inclusion and exclusion criteria will be reviewed.
3. The details of the study procedures, potential risks and benefits will be reviewed with
each subject and all potential questions will be answered.
4. Subjects' understating of all details of the study components will be ascertained and
they will be asked to sign the informed consent form.
5. A copy of the signed informed consent will be placed in study file and another copy
will be provided to each subject.
6. The study visit day will be scheduled within 2 weeks of the screening day.
7. All subjects will be asked to arrive on their first study day after an overnight fast.
They will be instructed to avoid caffeine and exercise for 24 hours.
Study Day #1 The subjects will arrive in the CRU in the morning. Subjects' understanding of
all study related procedures will be assessed and all remaining questions will be answered.
The following sequence of procedures will be followed for all enrolled subjects.
1. Physical exam including vital signs (Blood Pressure, Heart Rate, Weight, Height,
Respiration Rate, Temperature)
2. Urine pregnancy test for women of child bearing age. If positive, subjects will be
excluded.
Determination of peak oxygen consumption
3. Subjects will complete a continuous VO2 peak bicycle ergometer protocol.
1. Each subject will start peddling on a stationary bike
2. The initial power output (PO) will be set at 20 watts
3. The power output will be increased by 15 watts every 2-minutes until volitional
exhaustion.
4. Metabolic data will be collected during the protocol using standard open-circuit
spirometric techniques (Viasys Vmax Encore, Yorba Linda, CA)
5. Heart rate was assessed electrocardiographically.
6. VO2 peak will be chosen as the highest VO2 attained during the exercise protocol
On Day 2 of testing
1. Check Vitals (BP, HR, Wt., RR, Temp.)
2. Insert peripheral IV line Baseline renal blood flow measurement using contrast enhanced
ultrasonography
3. The Definity vial will be placed at room temperature before being used. It will be
activated after shaking the vial using Vialmax® for 45 seconds. It will be used
immediately after activation.
4. 0.4 ml of Definity will be mixed in 10 ml of preservative free saline.
5. Infusion of Definity into a peripheral vein will be started at 2 ml/min and titrated
for optimal image quality using a minipump (not to exceed 10 ml/min at any time).
6. Baseline contrast ultrasound imaging of right kidney will be performed with low
mechanical index (MI) of 0.2.
7. 4 - 5 ultrasound impulses with high MI of 1.0 and duration of 1 second will be used to
destruct the microbubbles in the kidney tissue
8. Ultrasound imaging of the kidney with low MI (0.2) will continue immediately after each
impulse for several seconds.
9. Infusion of Definity will stop at this point.
10. Vital signs will be monitored every 15 minutes and continuous pulse oximetry will be
performed during Definity administration.
11. Vital signs and pulse oximetry will be monitored every 15 minutes until 30 minutes
after discontinuation of Definity.
12. A urine dipstick will be performed by the study team 30 minutes after completion of
Definity infusion if a sample is available.
Constant load Exercise protocol
13. Subjects will complete 30 minutes of continuous cycling at the power output associated
with 85% of VO2peak from the continuous bicycle ergometer protocol. Metabolic data will
be collected as described above.
14. Once metabolic parameter are reached, exercise will be stopped and subject will be
asked to lie down on the bed Renal Blood flow measurement following exercise using
contrast enhanced ultrasonography
15. Immediately after completion of exercise protocol, steps 5 - 12 under day 2 procedures
will be repeated.
16. The study procedures will end at this point.
Inclusion Criteria:
- Healthy Adult - 18 to 50 years old
- All ethnicity and genders
Exclusion Criteria:
- Pregnancy or lactation
- Active infection
- Hypertension
- Chronic Medication Use except Multi Vitamin Use and Birth Control Medications
- Known history of a right to left intra-cardiac shunt
- Known history of pulmonary hypertension, including porto-pulmonary hypertension
- History of allergies to Definity®
- History of Liver or Kidney Transplant
- Patient on hemodialysis
- Has received iodinated contrast within 72 hours of admission to study
We found this trial at
1
site
Charlottesville, Virginia 22903
(434) 924-0311
Principal Investigator: Kambiz Kalantarinia, MD
Phone: 434-982-3198
University of Virginia The University of Virginia is distinctive among institutions of higher education. Founded...
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