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NCT Number: NCT05952011

Effect of Stellate Ganglion Block on Internal Mammary Artery Dynamics

This study aims to assess the effect of a stellate ganglion block on the flow and diameter of the internal mammary artery using the pulsatility index and transient time flowmetry(TTFM) in patients undergoing coronary artery bypass grafting.

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Key information

Conditions

Anesthesia

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ain shams university hospitals

Cairo, 11588, Egypt

About this study

The internal mammary artery (IMA) is the preferred graft for myocardial revascularization because of its superiority over venous grafts owing to long term patency, lower mortality rates and improved post-operative outcomes.

However, conduit spasm is a recognized complication of coronary artery bypass surgery mainly affecting the arterial conduits, a major concern that can lead to acute myocardial ischemia and may contribute to reduce graft patency.

Topical application or systemic administration of many pharmacological agents has been shown to reverse or prevent graft spasm, but side effects are reported with the use of these agents.

Various vasodilators that have been tried included various organic nitrates, calcium channel blockers, sodium nitroprusside (SNP) and papaverine.

Over the last few years, there were some studies, which investigated the effect of regional anesthesia techniques such as thoracic epidural anesthesia (TEA) and stellate ganglion block (SGB) for sympatholysis and studied its effects on internal mammary artery diameter .

The stellate ganglion block with local anesthetics have been widely used to provide pain relief to treat vascular spastic disorders of upper limbs, chronic pain conditions and treatment of refractory angina.

The stellate ganglion block has also been used for increasing radial artery (RA) blood flow and preventing RA spasm by sympathetic blockade in coronary artery bypass surgery.

In our study, two groups will be compared regarding IMA blood flow and diameter. The IMA pulsatility index and diameter will be measured before and after the stellate ganglion block during both the preoperative and intraoperative periods in both groups. Transit-time flowmetry (TTFM) will be used intraoperatively to assess IMA flow. Additionally, topical nitroglycerin will be applied intraoperatively in both groups, regardless of whether they received the stellate ganglion block.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age: 18 to 65 years.
  • Patients who will be slated to undergo elective coronary artery bypass graft surgery under Cardiopulmonary bypass in the Department of Cardiothoracic Surgery.

Exclusion criteria

  • Patient not willing to participate in the study.
  • Age more than 65 years.
  • Ejection fraction < 45%.
  • History of strokes / Transient ischaemic attacks and vertebro basilar insufficiency
  • History of Glaucoma.
  • History of allergy to local anaesthetic drugs.
  • Emergency coronary artery bypass graft or reoperations.
  • Pre-existing contralateral phrenic nerve palsy.
  • Patients with existing coagulopathy.
  • Allergy to nitroglycerin.

Treatment and study plan

Left stellate ganglion block

Procedure

patients will be positioned with head in midline position and mild extension of the neck. Cricoid cartilage will be identified by midline palpation of the neck and a 12 mega hertz ultrasound probe will be used. The airway will be identified by the shadow of the cricoid cartilage at the level of C6 vertebrae. The probe will be moved laterally to identify internal jugular vein, carotid artery and thyroid. Depth of ultrasound field will be adjusted to include the transverse process of the C6 vertebra. Following complete aseptic precautions, an echogenic insulated needle 5 cm long will be inserted under ultrasound guidance and directed toward the transverse process of the C6 vertebra. After the needle tip will make contact with the transverse process, it will be withdrawn 2 mm and 8 ml of 0.25% bupivacaine will be injected.

Topical Nitroglycerine

Drug

Application of topical Nitroglycerin solution to the LIMA pedicle graft during dissection of the vessel in both study arms.

Primary outcomes

  1. Effect of left stellate ganglion block on the left internal mammary artery blood flow after 10 minutes

    Time frame: 10 minutes after the left Stellate Ganglion Block

    LIMA blood flow will be measured using the pulsatility index

Secondary outcomes

  1. Change in Left Internal Mammary Artery (LIMA) diameter after left Stellate Ganglion Block

    Time frame: 10 minutes after block

    LIMA diameter measurement using ultrasound

  2. Effect of left stellate ganglion block on the left internal mammary artery blood flow after cardiopulmonary bypass

    Time frame: After cardiopulmonary bypass

    Measurement of LIMA blood flow using transit time flow measurement.

  3. Effect of left stellate ganglion block on mean blood pressure (MBP)

    Time frame: During surgery: baseline, after induction of anesthesia, at time after skin incision, after sternotomy, before and after cardiopulmonary bypass (CPB), after protamine and at the end of operation

    Effect of the block on hemodynamics

  4. Effect of left stellate ganglion block on heart rate (HR))

    Time frame: During surgery: baseline, after induction of anesthesia, at time after skin incision, after sternotomy, before and after cardiopulmonary bypass (CPB), after protamine and at the end of operation

    Effect of the block on hemodynamics

Sponsors and collaborators

Lead sponsor

Ain Shams University

Other

Registry information

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Jul 19, 2023
Registry last updated
Jun 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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