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

This study has been completed.
Sponsor:
Collaborators:
University of Brasilia
Hospital Sao Joao
Information provided by (Responsible Party):
GASPAR ROGERIO DA SILVA CHIAPPA, Principal Investigator, Hospital de Clinicas de Porto Alegre
ClinicalTrials.gov Identifier:
NCT01777659
First received: January 23, 2013
Last updated: November 7, 2013
Last verified: November 2013

January 23, 2013
November 7, 2013
March 2013
October 2013   (final data collection date for primary outcome measure)
Blood flow redistribution - baseline and 5 days later [ Time Frame: 1 day ] [ Designated as safety issue: Yes ]
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.
Blood flow redistribution [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
The ultrasound Doppler system will be equipped with two linear array transducers operating at an imaging frequency of 7- 8 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 (Vmean ), femoral blood flow (FBF) was calculated as Vmean 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.
Complete list of historical versions of study NCT01777659 on ClinicalTrials.gov Archive Site
Inspiratory and Expiratory Muscle Function [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
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.
Inspiratory and Expiratory Muscle Function [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
Inspiratory and expiratory muscle strength testing were performed using a pressure transducer (MVD-500 V.1.1 Microhard System, Globalmed, Porto Alegre, Brazil). Maximal inspiratory (PImax), and maximal static expiratory pressure (PEmax) were measured as previously described.
  • Pain Intensity [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    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 .
  • Opioid Analgesic Amount [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    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.
  • β-Endorphin Analysis [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    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).
  • Pain Intensity [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    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 .
  • Opioid Analgesic Amount [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    During the first 24 h (immediately, 6, 12 and 24 h) after CABG, the amount of additional analgesic dose (pethidine HCl 20 mg, maximum 1 mg/kg/day) was measured for patients in both groups.
  • β-Endorphin Analysis [ Time Frame: 5 day ] [ Designated as safety issue: Yes ]
    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).
 
Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery
Transcutaneous Electrical Nerve Stimulation Improves Vascular Conductance After Coronary Artery Bypass Graft Surgery

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).

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).

Interventional
Not Provided
Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Primary Purpose: Treatment
Acute Myocardial Infarction
Device: Transcutaneous electrical nerve stimulation
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.
Other Names:
  • TENS
  • electrical stimulation
  • Experimental: TENS CABG
    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.
    Intervention: Device: Transcutaneous electrical nerve stimulation
  • Placebo Comparator: P-TENS CABG
    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: Device: Transcutaneous electrical nerve stimulation
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
38
October 2013
October 2013   (final data collection date for primary outcome measure)

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.
Both
48 Years to 70 Years
No
Contact information is only displayed when the study is recruiting subjects
Brazil
 
NCT01777659
12-0317
No
GASPAR ROGERIO DA SILVA CHIAPPA, Principal Investigator, Hospital de Clinicas de Porto Alegre
Hospital de Clinicas de Porto Alegre
  • University of Brasilia
  • Hospital Sao Joao
Principal Investigator: Gaspar R Chiappa, Dr, ScD Federal University of Rio Grande do Sul
Hospital de Clinicas de Porto Alegre
November 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP