Optic Nerve Sheath Diameter and Cognitive Outcomes in Bentall Surgery (ONCOB)

March 5, 2026 updated by: Anıl Onur, Bursa Yuksek Ihtisas Training and Research Hospital

Evaluation of the Relationship Between Bilateral Optic Nerve Sheath Diameter (ONSD) Measurements and Postoperative Cognitive Functions in Bentall Surgeries: A Prospective Observational Study

Bentall surgery is a major cardiac procedure involving replacement of the ascending aorta, aortic root, and aortic valve, typically requiring cardiopulmonary bypass (CPB) and sometimes deep hypothermic circulatory arrest (DHCA). Due to its complexity, it carries a significant risk of postoperative neurological complications including stroke and postoperative cognitive dysfunction (POCD).

This prospective observational study aims to evaluate the relationship between perioperative bilateral optic nerve sheath diameter (ONSD) measurements obtained by ultrasound and postoperative cognitive functions in patients undergoing elective Bentall surgery. ONSD is a non-invasive surrogate marker of intracranial pressure that can be measured at the bedside using ultrasound.

In addition to routine hemodynamic monitoring and cerebral oximetry (NIRS), bilateral ONSD will be measured at predefined intraoperative and postoperative time points. Cognitive function will be assessed using the Montreal Cognitive Assessment (MoCA) test preoperatively and postoperatively, and delirium will be evaluated using the CAM-ICU scale during ICU stay. The association between perioperative ONSD values and postoperative cognitive outcomes, extubation time, ICU stay, and neurological complications will be analyzed.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Bentall procedure is a complex cardiac surgery involving replacement of the ascending aorta, aortic root, and aortic valve using a mechanical or bioprosthetic valve conduit and vascular graft. It is commonly performed for aortic aneurysm, aortic dissection, or connective tissue disorders such as Marfan syndrome. The procedure carries a mortality rate of 2-10% and a neurological complication rate of 3-8%, including stroke and postoperative cognitive dysfunction (POCD).Postoperative neurological complications in Bentall surgery are influenced by both patient-related and surgery-related factors. Patient-related risk factors include advanced age (>70 years), low educational level, pre-existing cognitive impairment, carotid artery stenosis, and acute type A dissection. Surgery-related risk factors include prolonged CPB and deep hypothermic arrest duration, cerebral perfusion technique, prosthesis type, prolonged mechanical ventilation, postoperative infection, low cardiac output, and anticoagulation compliance.

The optic nerve sheath (ONS) is a continuation of the intracranial dura mater surrounding the subarachnoid space. It expands in response to elevated intracranial pressure (ICP), particularly in the anterior retrobulbar region. Ultrasound measurement of ONSD is a well-validated, non-invasive bedside method for detecting elevated ICP and has been studied in various clinical settings.

Bentall surgeries involving CPB may affect intracranial dynamics through multiple mechanisms including oxygenation fluctuations, electrolyte disturbances, hemodilution, blood transfusion requirements, temperature variations, total circulatory arrest, prolonged surgical duration, and embolic events. Therefore, perioperative monitoring of intracranial status is of particular importance in these patients.

Study Procedures:

All patients will have the following baseline data recorded: age, sex, BMI, ASA classification, comorbidities, smoking and alcohol use, medications, ejection fraction (EF), EuroSCORE, and educational level.Preoperative assessments (T0) will include MoCA test, bilateral NIRS-based cerebral oximetry, and bilateral ONSD measurement by ultrasound while breathing room air.

Following preoxygenation and routine anesthesia induction, a central venous catheter will be placed. Bilateral NIRS and bilateral ONSD measurements will be performed at the following time points:

T0: Preoperative (room air) T1: 5 minutes after anesthesia induction T2: CPB initiation T3: Maximum hypothermic period T4: Aortic cross-clamp removal T5: CPB termination T6: After sternal closure, before ICU transfer

At each time point, mean arterial pressure (MAP), arterial blood gas values including hematocrit, PaO2, PaCO2, lactate, and pH will also be recorded.

Intraoperative data to be recorded include: anesthetic agent doses, total opioid and inhalation agent consumption, analgesic technique (fascial plane block or IV analgesia), surgical duration, CPB duration, cross-clamp duration, methylprednisolone dose if used, mannitol amount if used, cerebral perfusion type, TCA duration and temperature if applicable, surgical technique, prosthesis type, degree of hypothermia, vasopressor type and dose, blood transfusion volume, total urine output, and fluid balance.

Postoperative Follow-up:

Patients will be transferred to the cardiovascular surgery ICU and managed by the ICU team according to their standard protocols. The study team will not interfere with clinical management.

Postoperative assessments will include:

Bilateral ONSD measurement within the first postoperative hour and after extubation if applicable CAM-ICU delirium assessment twice daily during ICU stay and once daily on the ward RASS sedation score during ICU stay MoCA test after extubation and before hospital discharge VAS pain scores at postoperative 0, 6, 12, and 24 hours

Additional outcome data to be collected: extubation time, ICU length of stay, hospital length of stay, postoperative complications, need for mechanical circulatory support, reintubation, reoperation, blood transfusion volume, analgesic consumption, and mortality if applicable.

The observation period begins before anesthesia induction and ends at hospital discharge or mortality.

Study Type

Observational

Enrollment (Estimated)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
    • Yıldırım
      • Bursa, Yıldırım, Turkey (Türkiye), 16300
        • Recruiting
        • Bursa High Specialization Training and Research Hospital
        • Contact:
        • Principal Investigator:
          • Anıl O Onur, MD
        • Sub-Investigator:
          • Burak E Erdolu, Assoc Prof

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients aged 18-80 years scheduled for elective Bentall procedure at Bursa Yuksek Ihtisas Training and Research Hospital. The study population consists of patients with aortic pathologies including aortic aneurysm, aortic dissection, or connective tissue disorders such as Marfan syndrome, requiring ascending aorta and aortic root replacement with cardiopulmonary bypass (CPB) under general anesthesia.

Description

Inclusion Criteria:

  • Age between 18 and 80 years
  • Scheduled for elective Bentall procedure
  • Requiring cardiopulmonary bypass (CPB)
  • Willing to participate and able to provide informed consent
  • Able to complete the MoCA cognitive assessment test

Exclusion Criteria:

  • Age below 18 or above 80 years
  • Emergency Bentall surgery
  • Pre-existing diagnosed cognitive impairment or dementia
  • History of prior stroke or neurological disease
  • Significant carotid artery stenosis
  • Inability to complete the MoCA test (language barrier, illiteracy, visual or hearing impairment)
  • Refusal to participate or inability to provide informed consent
  • Patients with known psychiatric disorders
  • Reoperation (redo surgery)
  • Patients with severe renal or hepatic failure

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Relationship between perioperative bilateral ONSD measurements and postoperative cognitive function
Time Frame: Preoperative baseline to postoperative hospital discharge at 30 days
The Montreal Cognitive Assessment (MoCA) test will be administered preoperatively and after extubation and before hospital discharge to evaluate postoperative cognitive dysfunction (POCD). MoCA assesses multiple cognitive domains including memory, attention, executive function, and abstraction. The relationship between perioperative bilateral optic nerve sheath diameter (ONSD) measurements obtained by ultrasound and the change in MoCA scores will be analyzed to determine whether ONSD can serve as a predictive marker for postoperative cognitive dysfunction in patients undergoing Bentall surgery.This study will evaluate the relationship between changes in optical diameter and postoperative cognitive function. Whether any correlation exists will be assessed based on the study results.
Preoperative baseline to postoperative hospital discharge at 30 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bursa Yuksek Ihtisas Training and Research Hospital

Investigators

  • Principal Investigator: Anıl O Onur, MD, Bursa Yuksek Ihtisas Training and Research Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 30, 2025

Primary Completion (Estimated)

August 30, 2026

Study Completion (Estimated)

August 30, 2026

Study Registration Dates

First Submitted

March 1, 2026

First Submitted That Met QC Criteria

March 1, 2026

First Posted (Actual)

March 5, 2026

Study Record Updates

Last Update Posted (Actual)

March 6, 2026

Last Update Submitted That Met QC Criteria

March 5, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025/07-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data will not be shared due to patient confidentiality and privacy concerns in accordance with local ethical and legal regulations

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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