Cognitive Dysfunction in Hypertensive Patients Having Spine Surgery (HTN)

June 2, 2015 updated by: Eric J. Heyer, MD, PhD, Columbia University
While hypotension during general anesthesia has routinely been considered to be a tolerable abnormality with little clinical consequence, the proposed study takes the innovative approach of defining hypotensive events within the construct of a patient's own hypertensive status, fractional mean arterial blood pressure (fMAP). Because the investigators primary variable is within the control of anesthesia personnel, the study portends a potentially simple and easy to implement treatment. The introduction of neuropsychometric measures as the relevant evaluator of post-operative cognitive dysfunction is innovative, and may be more relevant to the average elderly patient than simple mortality.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

After major non-cardiac and non-cerebral surgery, postoperative cognitive dysfunction (POCD) occurs in a significant percentage of patients. The consequences of POCD are profound. Elderly patients having POCD at 1 week have an increased risk of disability or voluntary early retirement, and patients having POCD at 3 months have increased mortality.

The effect of low arterial blood pressure, called hypotension, during surgery on the incidence of POCD is not obvious. This effect has been obscured in a number of previous studies because, it was assumed that hypotension had to persist for minutes to hours to be deleterious, when, in fact, the duration is uncertain. In addition, patient outcomes were not analyzed as a function of a history of hypertension. In this research application, the investigators focus specifically on patients with a history of hypertension because their physiology is different than patients with normal arterial blood pressure. These hypertensive patients may be unable to compensate for low arterial blood pressure by a process called cerebral autoregulation. As a result, patients with a history of hypertension may be at greater risk for decreased cerebral perfusion and cerebral ischemia secondary to decreased systemic arterial blood pressure even during surgery for procedures not thought to put the brain at risk of ischemia.

In a prior retrospective study, the investigators analyzed hemodynamic data from fifty elderly (average age >60 years) patients having simple lumbar spine surgery, which is not thought to be associated with cerebral ischemia. These patients were all examined with a battery of neuropsychometric tests before and after surgery. Patients with a history of hypertension had cognitive changes that are dependent on the lowest fractional mean arterial blood pressure (fMAP), where fMAP is mean arterial blood pressure (MAP) divided by baseline MAP. Such changes were not found in patients without a history of hypertension. This relationship did not depend on the steady state fMAP or the highest fMAP reached in either group.

To confirm and extend these results the investigators therefore propose and hypothesize that: In patients with a history of hypertension, compared to patients without this history, low fMAPs during induction predict cognitive performance after surgery.

To evaluate these hypotheses the investigators will determine the incidence of post-operative cognitive dysfunction (POCD) as a function of the fMAP in hypertensive and normotensive patients undergoing elective simple lumbar spine surgery.

If the proposed study demonstrates that acute intra-operative episodes of hypotension are deleterious to cognitive performance in patients with hypertension, and that there are demonstrable consequences in terms of QOL measures, the possibility of a direct and low cost intervention will be available that will lead directly to an efficacy trial using non-invasive measures of cerebral blood flow algorithms to prevent POCD.

The investigators plan to conduct a multicenter study in which 200 elderly patients (>60 years) are tested with a validated battery of 6 neuropsychometric tests before simple elective lumbar spine surgery (microdiscectomy or 1-2 level laminectomies without fusions lasting <5 hours and not requiring blood transfusions) and two times after surgery, at 24 hours and at 1 month. Two questionnaires for QOL will be performed before surgery and at 1 month. Patients will be questioned whether they have a history of hypertension, and, if they do, then its duration and treatment.

Our analysis will be based on comparing the fMAP to the neuropsychometric performance before and after surgery. To see if neuropsychometric changes occur as a component of a routine anesthetic, anesthesiologists will not be given a specific protocol for intraoperative management.

The primary outcome measure will be changes in test performance between baseline and the post-operative period at 1 day and 1 month. This primary measure will be a rating of overall change in performance compared to three values of fMAPs: lowest, steady state and highest fMAP attained. Our analysis will also include uni- and multi-variate analyses which will include and QOL.

Study Type

Observational

Enrollment (Actual)

179

Contacts and Locations

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

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10032
        • Columbia University

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

60 years to 90 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients >60 years old will be recruited who are scheduled for elective simple spine surgery (microdiskectomy or 1-2 level laminectomies without fusion) and lasting <5 hours without blood transfusion.

Description

Inclusion Criteria:

  • elective spine surgery
  • > 60 years old
  • < 5 hours of surgery
  • microdiskectomy
  • 1-2 levels of spinal laminectomies

Exclusion Criteria:

  • transfusions
  • > 5 hours of surgery
  • > 2 levels of laminectomies
  • spinal instrumentation

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Hypertension (case)
Elderly patients 60 years old or older undergoing simple lumbar spine surgery under general anesthesia will receive neurologic/neuropsychometric examinations.
Procedure: Lumbar spine surgery
(non-experimental) we do not intend to change the criteria of selection for simple lumbar spine surgery, anesthesia, or the postoperative management of the patients studied.
Other: Neurologic/neuropsychometric examinations
To measure postoperative cognitive dysfunction.
Normotension (control)
Middle-aged patients (40-60 years) undergoing simple lumbar spine surgery under general anesthesia as controls to compare their performance to those patients >60 years - will also receive neurologic/neuropsychometric examinations.
Procedure: Lumbar spine surgery
(non-experimental) we do not intend to change the criteria of selection for simple lumbar spine surgery, anesthesia, or the postoperative management of the patients studied.
Other: Neurologic/neuropsychometric examinations
To measure postoperative cognitive dysfunction.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Neuropsychometric changes at 1 day
Time Frame: Baseline to 1 Day
The investigators will determine whether there are neuropsychometric changes associated with simple spine surgery as a function of arterial blood pressure measurements relative to the patient's baseline values at 1 day.
Baseline to 1 Day

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Neuropsychometric changes at 1 Month
Time Frame: Baseline to 1 Month
The investigators will determine whether there are neuropsychometric changes associated with simple spine surgery as a function of arterial blood pressure measurements relative to the patient's baseline values at 1 month.
Baseline to 1 Month

Collaborators and Investigators

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

Sponsor

Columbia University

Collaborators

Weill Medical College of Cornell University

Investigators

  • Principal Investigator: Eric J Heyer, MD, PhD, Columbia University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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

January 1, 2009

Primary Completion (ACTUAL)

January 1, 2013

Study Completion (ACTUAL)

December 1, 2014

Study Registration Dates

First Submitted

June 2, 2010

First Submitted That Met QC Criteria

June 9, 2010

First Posted (ESTIMATE)

June 10, 2010

Study Record Updates

Last Update Posted (ESTIMATE)

June 4, 2015

Last Update Submitted That Met QC Criteria

June 2, 2015

Last Verified

June 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AAAD3838

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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