Cognitive Dysfunction in Hypertensive Patients Having Spine Surgery
| Status: | Completed |
|---|---|
| Conditions: | Cognitive Studies, High Blood Pressure (Hypertension) |
| Therapuetic Areas: | Cardiology / Vascular Diseases, Psychiatry / Psychology |
| Healthy: | No |
| Age Range: | 60 - 90 |
| Updated: | 2/7/2015 |
| Start Date: | January 2009 |
| End Date: | December 2014 |
| Contact: | Kaitlin A Mallon, BA |
| Email: | km2954@cumc.columbia.edu |
| Phone: | 2123058949 |
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.
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.
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.
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.
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
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