Trial Outcomes & Findings for Variability in Adrenergic Response (NCT NCT00838695)

Results Overview

ED50 is a measurement of vein constriction and indicates 50% of maximal constriction after being given medication phenylephrine, representing sensitivity to the drug. Phenylephrine was infused at increasing dose rates, ranging from 12-9600 ng/min. The infusion at each dose rate lasted 7 minutes, with the vein diameter measured during the last 2 minutes of the infusion. The number represents the ng/ml of phenylephrine needed to reach 50% of maximal vein constriction. ED50 values were not normally distributed and were log-transformed for analysis and expressed as geometric means.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

106 participants

Primary outcome timeframe

70 minutes

Results posted on

2018-10-26

Participant Flow

Subjects were recruited by advertisement within the Vanderbilt University campus and through the Vanderbilt University Clinical Research Center study volunteer database,

Participant milestones

Participant milestones
Measure	African Americans Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)	Caucasians Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)
Overall Study STARTED	42	64
Overall Study COMPLETED	42	64
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Variability in Adrenergic Response

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	African Americans n=42 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)	Caucasians n=64 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)	Total n=106 Participants Total of all reporting groups
Age, Continuous	28.1 years STANDARD_DEVIATION 8 • n=5 Participants	26.9 years STANDARD_DEVIATION 6.8 • n=7 Participants	27 years STANDARD_DEVIATION 7 • n=5 Participants
Sex: Female, Male Female	18 Participants n=5 Participants	31 Participants n=7 Participants	49 Participants n=5 Participants
Sex: Female, Male Male	24 Participants n=5 Participants	33 Participants n=7 Participants	57 Participants n=5 Participants
Region of Enrollment United States	42 Participants n=5 Participants	64 Participants n=7 Participants	106 Participants n=5 Participants
plasma norepinephrine	179.5 pg/ml STANDARD_DEVIATION 70.8 • n=5 Participants	162.3 pg/ml STANDARD_DEVIATION 58 • n=7 Participants	168.9 pg/ml STANDARD_DEVIATION 63.2 • n=5 Participants
plasma epinephrine	21.0 pg/ml STANDARD_DEVIATION 15.6 • n=5 Participants	18.5 pg/ml STANDARD_DEVIATION 12.5 • n=7 Participants	19.4 pg/ml STANDARD_DEVIATION 13.7 • n=5 Participants

PRIMARY outcome

Timeframe: 70 minutes

ED50 is a measurement of vein constriction and indicates 50% of maximal constriction after being given medication phenylephrine, representing sensitivity to the drug. Phenylephrine was infused at increasing dose rates, ranging from 12-9600 ng/min. The infusion at each dose rate lasted 7 minutes, with the vein diameter measured during the last 2 minutes of the infusion. The number represents the ng/ml of phenylephrine needed to reach 50% of maximal vein constriction. ED50 values were not normally distributed and were log-transformed for analysis and expressed as geometric means.

Outcome measures

Outcome measures
Measure	African Americans n=42 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)	Caucasians n=64 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)
ED50 After Phenylephrine	172 ng/min Interval 115.0 to 256.0	310 ng/min Interval 222.0 to 434.0

SECONDARY outcome

Timeframe: baseline to 2 minutes

Population: A subset of participants (57 of the 106) in the primary outcome measure also participated in the cold pressor test.

change in systolic and diastolic blood pressure, comparing before and after cold pressor test. A subset of 57 participants (of the 106) who were in the primary outcome measure also participated in the cold pressor test.

Outcome measures

Outcome measures
Measure	African Americans n=21 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)	Caucasians n=36 Participants Subjects' hand veins will be measured for maximum constriction while being infused with phenylephrine, and then mental stress and cold pressor testing Phenylephrine: Intravenous phenylephrine at low doses (approximately 10 doses ranging from 0-5000 ng/min) Intravenous nitroglycerin at low doses (approximately 10 doses ranging from 0.05-100 ng/min)
Change in Blood Pressure Change in Systolic Blood Pressure	23.0 mmHg Standard Deviation 12.3	18.9 mmHg Standard Deviation 11.7
Change in Blood Pressure Change in Diastolic Blood pressure	16.9 mmHg Standard Deviation 9.3	16.4 mmHg Standard Deviation 8.8

Adverse Events

African Americans

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Caucasians

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. C. Michael Stein

VAnderbilt University Medical Center

Phone: 615-936-3420

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place