Preoperative non-invasive stress testing
BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.b5401 (Published 18 January 2010) Cite this as: BMJ 2010;340:b5401All rapid responses
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Pre-operative RCRI score to identify patients who will benefit from non-invasive cardiac stress test
Dear Editor
Pre-operative cardiovascular risk
assessment of patient
is a common referral to cardiology outpatient department.
Without any objective
risk assessment, it is very difficult to decide what
diagnostic test to use.
Invariably every patient gets non-invasive stress test for
assessment if
referred to cardiology.
Your review highlights the importance
of Revised Cardiac
Risk Index (1) (Table 1; Table 2).
Table
1.Revised
Cardiac Risk Index score system.
Criteria |
Points |
High-risk |
1 |
History |
1 |
History |
1 |
History |
1 |
Preoperative |
1 |
Preoperative |
1 |
Total |
RCRI |
Table
2.Final
RCRI risk score and associated Risk
Group.
Final |
Risk |
0 |
Low |
1-2 |
Intermediate |
3-6 |
High |
In National Health Service (NHS) if we
were to request
non-invasive stress test for every cardiac patient’s pre-
operative assessment,
it would led to huge financial and resource burden. I
propose a model were in
surgical outpatient pre-assessment clinics can risk stratify
patients according
to the RCRI score and appropriately refer to cardiology for
non-invasive stress
test and cardiology review. By using this model, surgical
colleagues can
objectively communicate to cardiologists and seek their
advice on treatment
optimization and pre-operative cardiac assessment. This
would hopefully reduce
outpatient referrals to cardiology and also help
cardiologists to optimise
treatment in the right group of
patients.
This needs to be further assessed by
auditing referral
practice for pre-operative cardiac assessment in local
secondary care settings.
Other aspects to look into will include retrospective RCRI
score analysis and
auditing how many patients had pre-operative stress
assessment.
References:
(1)
Lee
TH, Marcantonio ER, Mangione
CM, Thomas EJ, Polanczyk CA, Cook
EF, et al.
Derivation and prospective validation of a simple index for
prediction of
cardiac risk of major noncardiac
surgery.
Circulation1999;100:1043-
9.
Competing interests:
None declared
Competing interests: No competing interests
Preoperative evaluation should reduce risk and facilitate resource allocation.
Preoperative testing should reduce morbidity and mortality, and allow
risk
stratification so that precious critical care beds can be utilized
appropriately.
The current paradigm for reduction of cardiac risk in non-cardiac surgery
is
mainly predicated on preoperative testing for myocardial ischaemia (1).
Some
authors have proposed that the major determinant of perioperative
mortality
is the inability of the heart to increase its output in response to
surgical
stress (2). This hypothesis is supported by recent work where heart
failure
rather than coronary artery disease was shown to significantly increase
the
risk of death after major non-cardiac surgery (3, 4).
Cardiopulmonary Exercise Testing (CPET) provides an objective measure
of
fitness for surgery, in that it assesses functional capacity and detects
cardiac
disease. During CPET oxygen consumption and carbon dioxide production are
measured in the course of a ramped exercise test. The point at which
oxygen
delivery becomes inadequate to meet the energy demand of the body
through aerobic metabolism alone is termed the anaerobic threshold. This
point can be identified easily in most individuals and is expressed as the
oxygen consumption at the onset of supplementary anaerobic metabolism in
ml/kg/min. The measurement of anaerobic threshold is a submaximal test
that is relevant to perioperative risk assessment. Older et al. used CPET
to
measure the anaerobic threshold in 187 elderly patients before major
abdominal surgery (5). Patients with an anaerobic threshold < 11
ml/kg/min
had a mortality of 18 % compared with those with an anaerobic threshold
>
11 ml/kg/min whose mortality was 0.8 %. In patients who exhibited signs of
ischaemia during the testing process, mortality was 42 % for patients
whose
anaerobic threshold was < 11 ml/kg/min, whilst only 4 % for those whose
anaerobic threshold was > 11 ml/kg/min. Poor ventricular function, as
measured by the anaerobic threshold, predicted a high risk for major
surgery,
particularly when coupled with evidence of myocardial ischaemia.
CPET allows physicians to plan a patient’s preoperative interventions
and
postoperative critical care utilization. As well as identifying those at
high risk
of perioperative complications, it can also identify those patients who
are at
low risk for complications. It is this latter group that can safely
receive their
postoperative care outside of critical care facilities.
1. Fleisher LA, Beckman JA, Brown KA, Calkins H, Chaikof E,
Fleischmann KE,
et al. ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation
and care for noncardiac surgery: a report of the American College of
Cardiology/American Heart Association Task Force on Practice Guidelines
(Writing Committee to Revise the 2002 Guidelines on Perioperative
Cardiovascular Evaluation for Noncardiac Surgery): developed in
collaboration
with the American Society of Echocardiography, American Society of Nuclear
Cardiology, Heart Rhythm Society, Society of Cardiovascular
Anesthesiologists, Society for Cardiovascular Angiography and
Interventions,
Society for Vascular Medicine and Biology, and Society for Vascular
Surgery.
Circulation. 2007 Oct 23;116(17):e418-99.
2. Older P, Smith R, Hall A, French C. Preoperative cardiopulmonary
risk
assessment by cardiopulmonary exercise testing. Crit Care Resusc. 2000
Sep;2(3):198-208.
3. Hernandez AF, Whellan DJ, Stroud S, Sun JL, O'Connor CM, Jollis
JG.
Outcomes in heart failure patients after major noncardiac surgery. J Am
Coll
Cardiol. 2004 Oct 6;44(7):1446-53.
4. Hammill BG, Curtis LH, Bennett-Guerrero E, O'Connor CM, Jollis JG,
Schulman KA, et al. Impact of heart failure on patients undergoing major
noncardiac surgery. Anesthesiology. 2008 Apr;108(4):559-67.
5. Older P, Smith R, Courtney P, Hone R. Preoperative evaluation of
cardiac
failure and ischemia in elderly patients by cardiopulmonary exercise
testing.
Chest. 1993 Sep;104(3):701-4.
Competing interests:
None declared
Competing interests: No competing interests