Effects of Vasopressors on Cerebral Hemodynamics in Patients With Carotid Endarterectomy (MRI Part)

Study Overview
=================
Brief Summary
-----------------
This study was a single-center, exploratory, randomized controlled trial. First, the effects of ephedrine, phenylephrine, or norepinephrine on cerebral blood flow hemodynamics in CEA patients were evaluated using DSC-MRI to investigate the specific mechanisms of the three vasopressors on cerebral blood flow and oxygen metabolism in brain tissues.

Detailed Description
-----------------
Carotid endarterectomy is a procedure used to remove plaque from the common and internal carotid arteries and improve cerebral perfusion. Clinical studies have demonstrated the effectiveness of this procedure in both symptomatic and asymptomatic patients. intraoperative circulatory management challenges in CEA include the following: ① The incidence of preoperative combined coronary artery disease, hypertension and diabetes mellitus is relatively high in patients undergoing carotid endarterectomy, and there is a pathological basis for systemic vascular injury, increasing the risk of perioperative cardiovascular and cerebrovascular complications, such as myocardial ischemia and stroke. ② During the CEA procedure, the common carotid artery, internal carotid artery and external carotid artery and the superior thyroid artery need to be blocked respectively, the source of blood supply to the cerebral hemisphere on the operated side is reduced and depends only on the Willis circle supply. ③ Carotid sinus pressure receptor pull stimulation causes circulatory fluctuations. During CEA, a relatively high arterial pressure is required to provide adequate cerebral perfusion. However, achieving this target blood pressure level intraoperatively can be challenging due to given conditions, the presence of induction drugs and anesthetics. Therefore, it is particularly important to maintain cerebral hemodynamic stability and ensure tissue perfusion with intraoperative use of vasopressers. The purpose of this study was to evaluate the effects of ephedrine, phenylephrine, or norepinephrine on cerebral blood flow hemodynamic in CEA patients using DSC-MRI to investigate the specific mechanisms of the three boosting agents on cerebral blood flow and oxygen metabolism in brain tissues.

Official Title
-----------------
Effects of Vasopressors on Cerebral Hemodynamics in Patients With Carotid Endarterectomy Under General Anesthesia(MRI Part): a Randomized Controlled Study

Conditions
-----------------
Carotid Endarterectomy

Intervention / Treatment
-----------------
* Drug: Ephedrine
* Drug: Phenylephrine
* Drug: Norepinephrine


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: age 40-80 years. elective carotid endarterectomy. Signed informed consent Exclusion Criteria: ASA classification IV - VI. renal failure (estimated glomerular filtration rate less than 60 ml/min.m2). cardiac arrhythmias. Allergy to ephedrine, phenylephrine or norepinephrine, gadobutrol. patients with preoperative TCD suggesting poor temporal window signal. patients with severe carotid artery stenosis with no flow signal detected by TCD Patients with tandem lesions of carotid artery stenosis

Ages Eligible for Study
-----------------
Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ephedrine<br>receive ephedrine (configured concentration 2 mg/mL). The individualized blood pressure control target was a 20% increase in baseline blood pressure, and the target blood pressure value was used as the basis for adjusting the dosing or pumping rate. | Drug: Ephedrine<br>* vasopressor<br>|
| Experimental: Phenylephrine<br>receive intravenous infusion of phenylephrine (configured concentration 0.1 mg/mL) The individualized blood pressure control target was a 20% increase in baseline blood pressure, and the target blood pressure value was used as the basis for adjusting the dosing or pumping rate. | Drug: Phenylephrine<br>* vasopressor<br>|
| Experimental: norepinephrine<br>intravenous infusion of norepinephrine (configured concentration of 6 μg/ml).The individualized blood pressure control target was a 20% increase in baseline blood pressure, and the target blood pressure value was used as the basis for adjusting the dosing or pumping rate. | Drug: Norepinephrine<br>* vasopressor<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regional Cerebral Blood Flow | This outcome is measured by Dynamic susceptibility contrast-enhanced perfusion-weighted imaging. | 10 minutes after entering the operating room; 10 minutes after intubation ;5 minutes after administration of vasopressors | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regional oxygen saturation index | This outcome is measured by Near Infrared Spectroscopy | 10 minutes after entering the operating room; 10 minutes after intubation ;5 minutes after administration of vasopressors | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
carotid endarterectomy, ephedrine, phenylephrine, norepinephrine, cerebrovascular circulation, cerebral blood flow hemodynamics