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Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery (TEBCABG)

Primary Purpose

Acute Myocardial Infarction

Status
Completed
Phase
Not Applicable
Locations
Brazil
Study Type
Interventional
Intervention
Transcutaneous electrical nerve stimulation
Sponsored by
Hospital de Clinicas de Porto Alegre
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Acute Myocardial Infarction focused on measuring exercise, neuromodulation, blood flow, exercise capacity

Eligibility Criteria

48 Years - 70 Years (Adult, Older Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  • a previous history of more than 1 vessel coronary artery disease,
  • lifelong abstinence from tobacco, and
  • formal indication for CABG, according to established guideline.

Exclusion Criteria:

  • Patients older than 70 years of age, with chronic renal failure, or with unstable angina in the 48 h prior to CABG, moderate or severe valve disease, complex cardiac arrhythmias, stroke, and/or inability to exercise the lower limbs.

Sites / Locations

  • Hospital de Clinicas de Porto Alegre

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Placebo Comparator

Arm Label

TENS CABG

P-TENS CABG

Arm Description

Eligible patients will be randomized to a transcutaneous electrical nerve stimulation program (TENS; n = 20) or to placebo-TENS (P-TENS; n = 18). All patients were followed by their own physicians, received routine nursing assistance, and were visited daily by one of the investigators, but P-TENS group will be not exposed to any specific electrical stimulation or motor physical intervention.

Patients will be treated with placebo-TENS (P-TENS) condition for 5 days (4 times/day; 30 min/session) applied on cervical region (C7-T4). P-TENS device underwent modifications in its internal programming: the control capacitor of the time constant was changed and the active time between pulses was modified from 330 milliseconds to 33 seconds, in order to prevent an analgesic effect (33).

Outcomes

Primary Outcome Measures

Blood flow redistribution - baseline and 5 days later
The ultrasound Doppler system will be equipped with two linear array transducers operating at an imaging frequency of 7- 8 megahertz (MHz). The common femoral artery of the left leg will be insonated distal to the inguinal ligament, 2-3 cm proximal to the bifurcation. Using femoral artery diameter and mean blood velocity (MBF), femoral blood flow (FBF) was calculated as MBF π x (vessel diameter/2)2 x 60. Femoral vascular resistance (FVR) and femoral vascular conductance (FVC) were calculated as (MBP/FBF) and (FBF/MBP * 100 mm Hg), the conductance multiplied by 100 mmHg so that the conductance units will be similar to the units of femoral blood flow (10, 45). The magnitude of reduction FVC (expressed in %) was calculated as vascular conductance during exercise (% change) - conductance at rest (% change) expressed by % of baseline.

Secondary Outcome Measures

Inspiratory and Expiratory Muscle Function
Inspiratory and expiratory muscle strength testing were performed using a pressure transducer (MVD-500 V.1.1 Micro Hard System, Global Med, Porto Alegre, Brazil). Maximal inspiratory (PImax), and maximal static expiratory pressure (PEmax) were measured as previously described.

Full Information

First Posted
January 23, 2013
Last Updated
November 7, 2013
Sponsor
Hospital de Clinicas de Porto Alegre
Collaborators
University of Brasilia, Hospital Sao Joao
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1. Study Identification

Unique Protocol Identification Number
NCT01777659
Brief Title
Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery
Acronym
TEBCABG
Official Title
Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery
Study Type
Interventional

2. Study Status

Record Verification Date
November 2013
Overall Recruitment Status
Completed
Study Start Date
March 2013 (undefined)
Primary Completion Date
October 2013 (Actual)
Study Completion Date
October 2013 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
Hospital de Clinicas de Porto Alegre
Collaborators
University of Brasilia, Hospital Sao Joao

4. Oversight

Data Monitoring Committee
No

5. Study Description

Brief Summary
The investigators will test the hypothesis that transcutaneous electrical nerve stimulation (TENS) may attenuate peripheral vasoconstriction and to improve blood flow redistribution during handgrip exercise in acute myocardial infarction (AMI) patients after Coronary Arterial Bypass Graft Surgery (CABG).
Detailed Description
Thirty-eight patients will be randomized to a (4 times/day; 30 min/session) for 5-day program of TENS (n = 20) or to placebo-TENS (P-TENS, n = 18) applied on cervical region (C7-T4). Acute sympathetic stimulation by cold pressor test (CPT), Maximal voluntary contraction (MVC), Femoral blood flow (FBF) and femoral vascular conductance (FVC) will be measured as primary outcome pre and post-CABG, even as the 6-minute walk test (6-MWT), Inspiratory and expiratory muscle strength (PImax and PEmax) and β-endorphin as a secondary clinical parameters. In addition, amount of opioid analgesic and pain intensity also will be measured throughout at first 24 hours after CABG (immediately, 6, 12 and 24 hours).

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Acute Myocardial Infarction
Keywords
exercise, neuromodulation, blood flow, exercise capacity

7. Study Design

Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
ParticipantCare ProviderInvestigator
Allocation
Randomized
Enrollment
38 (Actual)

8. Arms, Groups, and Interventions

Arm Title
TENS CABG
Arm Type
Experimental
Arm Description
Eligible patients will be randomized to a transcutaneous electrical nerve stimulation program (TENS; n = 20) or to placebo-TENS (P-TENS; n = 18). All patients were followed by their own physicians, received routine nursing assistance, and were visited daily by one of the investigators, but P-TENS group will be not exposed to any specific electrical stimulation or motor physical intervention.
Arm Title
P-TENS CABG
Arm Type
Placebo Comparator
Arm Description
Patients will be treated with placebo-TENS (P-TENS) condition for 5 days (4 times/day; 30 min/session) applied on cervical region (C7-T4). P-TENS device underwent modifications in its internal programming: the control capacitor of the time constant was changed and the active time between pulses was modified from 330 milliseconds to 33 seconds, in order to prevent an analgesic effect (33).
Intervention Type
Device
Intervention Name(s)
Transcutaneous electrical nerve stimulation
Other Intervention Name(s)
TENS, electrical stimulation
Intervention Description
Patients will be treated with conventional TENS (ENDOMED 684 Device, ENRAF-Nonius B.V., Rotterdam, Netherlands) for 5 days (4 times/day; 30 min/session) applied on cervical region (C7-T4). TENS intervention was applied as described elsewhere.
Primary Outcome Measure Information:
Title
Blood flow redistribution - baseline and 5 days later
Description
The ultrasound Doppler system will be equipped with two linear array transducers operating at an imaging frequency of 7- 8 megahertz (MHz). The common femoral artery of the left leg will be insonated distal to the inguinal ligament, 2-3 cm proximal to the bifurcation. Using femoral artery diameter and mean blood velocity (MBF), femoral blood flow (FBF) was calculated as MBF π x (vessel diameter/2)2 x 60. Femoral vascular resistance (FVR) and femoral vascular conductance (FVC) were calculated as (MBP/FBF) and (FBF/MBP * 100 mm Hg), the conductance multiplied by 100 mmHg so that the conductance units will be similar to the units of femoral blood flow (10, 45). The magnitude of reduction FVC (expressed in %) was calculated as vascular conductance during exercise (% change) - conductance at rest (% change) expressed by % of baseline.
Time Frame
1 day
Secondary Outcome Measure Information:
Title
Inspiratory and Expiratory Muscle Function
Description
Inspiratory and expiratory muscle strength testing were performed using a pressure transducer (MVD-500 V.1.1 Micro Hard System, Global Med, Porto Alegre, Brazil). Maximal inspiratory (PImax), and maximal static expiratory pressure (PEmax) were measured as previously described.
Time Frame
5 day
Other Pre-specified Outcome Measures:
Title
Pain Intensity
Description
A visual analog scale (VAS) for assessing current pain intensity will be used to evaluate pain from 0 to 10, where 0 means no pain and 10 indicates severe pain, being applied on the first and on the 5th day after CABG .
Time Frame
5 day
Title
Opioid Analgesic Amount
Description
During the first 24 h (immediately, 6, 12 and 24 h) after CABG, the amount of additional analgesic dose (pethidine hydrochloride (HCl) 20 mg, maximum 1 mg/kg/day) was measured for patients in both groups.
Time Frame
5 day
Title
β-Endorphin Analysis
Description
Ten milliliters of venous blood will be taken by the phlebotomist. 3 ml of which will be stored in ethylenediaminetetraacetic acid (EDTA) for analysis of a differential white cell count. Seven ml of blood will be divided between an EDTA tube and a lithium heparin (LH) gel tube. These blood samples will be centrifuged and frozen until assayed. β-endorphin was measured by sandwich enzyme immunoassay (ELISA) kit (Phoenix Pharmaceuticals, Inc., USA).
Time Frame
5 day

10. Eligibility

Sex
All
Minimum Age & Unit of Time
48 Years
Maximum Age & Unit of Time
70 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: a previous history of more than 1 vessel coronary artery disease, lifelong abstinence from tobacco, and formal indication for CABG, according to established guideline. Exclusion Criteria: Patients older than 70 years of age, with chronic renal failure, or with unstable angina in the 48 h prior to CABG, moderate or severe valve disease, complex cardiac arrhythmias, stroke, and/or inability to exercise the lower limbs.
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Gaspar R Chiappa, Dr, ScD
Organizational Affiliation
Federal University of Rio Grande do Sul
Official's Role
Principal Investigator
Facility Information:
Facility Name
Hospital de Clinicas de Porto Alegre
City
Porto Alegre
State/Province
Rio Grande do Sul
ZIP/Postal Code
90035-007
Country
Brazil

12. IPD Sharing Statement

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Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery

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