Effect of Blood Pressure on rSO2 in Carotid Endarterectomy (CEA)

Study Overview
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Brief Summary
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Carotid endarterectomy (CEA) is the recommended treatment for symptomatic high degree stenosis of the internal carotid artery (ICA). ICA obstruction is often associated with an impaired cerebral autoregulation, implicating that cerebral perfusion pressure becomes dependent on systemic blood pressure. Therefore, to maintain cerebral perfusion pressure in this type of patients intraoperative hypotension needs to be avoided. Different short-acting agents such as phenylephrine, (a drug with vasoconstrictive properties), or ephedrine (a drug with vasoconstrictive properties combined with an increase in heart rate) can be used to correct intra-operative hypotension. In healthy subjects these agents affect the cerebral perfusion differently despite an identical effect on the systemic blood pressure. Cerebral perfusion decreases after phenylephrine administration while it is preserved after the use of ephedrine. The optimal agent for correcting hypotension in CEA patients, and thus in a situation of an impaired cerebral autoregulation, is unknown. Therefore, the investigators propose to perform a prospective study observing the effect of phenylephrine and ephedrine on cerebral perfusion to make a recommendation regarding the use of either phenylephrine or ephedrine during CEA.

Official Title
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The Effect of Phenylephrine Versus Ephedrine on Cerebral Perfusion During Carotid Endarterectomy

Conditions
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Intra-operative Hypotension, Carotid Stenosis

Intervention / Treatment
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* Drug: Administration of phenylephrine
* Drug: Administration of ephedrine


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: All patients undergoing CEA in the University Medical Centre Utrecht and having an appropriate temporal bone window for reliable perioperative TCD monitoring could be included. All patients must have given written informed consent. Exclusion criteria: Not having a temporal bone window appropriate for TCD measurement Not willing to give informed consent. If the effect on BP of the given agents is insufficient (if relative hypotension persists five minutes after administration).
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Ephedrine<br> | Drug: Administration of ephedrine<br>* Ephedrine: 5- 10 mg<br>|
| Active Comparator: Phenylephrine<br> | Drug: Administration of phenylephrine<br>* Phenylephrine: 50-100µg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cerebral perfusion (rSO2) measured using Near Infrared Spectroscopy | A continuous measurement during surgery will be performed. However for further analysis only a short time frame will be used. | (day 1) Monitoring will take place only on the day of operation. No further follow-up. Timeframe is 1 day. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood velocity (Vmca) measured using transcranial Doppler | A continuous measurement during surgery will be performed. However for further analysis only a short time frame will be used. | Within 18 months in consecutive patients undergoing carotid endarterectomy. Endpoints will only be assessed during actual surgery (approximately 90 minutes in total) no data will be assessed during follow-up. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cerebral autoregulation