Download routine stress testing to risk stratify and rule out occult ischemia

Preoperative Assessment of the Cardiac
Patient for Non-cardiac Surgery
John R. Butterly, M.D.
Dartmouth-Hitchcock
Issues
Overview of ischemic
heart disease
 General
considerations

 Predictors
– Clinical
– Procedural

– Anesthetic
– Operative

Clinical assessment
of risk
Disease specific states
– CAD, hypertension,
CHF, valvular

Preoperative therapy
Dartmouth-Hitchcock
Bottom Line
 Indications
for evaluation/intervention are
the same as in the general population
 Pre-operative evaluation should be seen as
an opportunity to provide recommendations
for care over the long-term as well as the
immediate, peri-operative period
 Intervention is rarely necessary to lower the
risk of non-cardiac surgery
Dartmouth-Hitchcock
Overview of Ischemic Heart Disease
 Anatomy
 Physiology
– coronary
– left ventricular
– patient
Dartmouth-Hitchcock
Etiology of Ischemia
 Supply
–
–
–
–
blood O2 carrying capacity
cardiac output
systemic vascular resistance
coronary resistance
(Poiseuille)
coronary resistance ~ 1/R4
 Demand
– Major determinants of MVO2
» systolic work



heart rate
blood pressure (afterload)
duration of systole
» ventricular wall tension (LaPlace)
T = PR
» contractility
» myocardial mass
Dartmouth-Hitchcock
Ischemia vs Infarction
 Implications
of demand related problem vs supply
related problem
– stability
– biology
» endothelial function
» plaque rupture/thrombosis
Dartmouth-Hitchcock
General Considerations
 A substantial
proportion of all deaths in most series
of non-cardiac operations arise from cardiovascular
complications.
 Stresses to cardiovascular system
– decrease in myocardial contractility & respiration
– fluctuations in temperature, afterload, preload, blood
volume, & autonomic nervous system output
Dartmouth-Hitchcock
General Considerations
 Possible
complications of anesthesia &
surgery may impose additional burdens
–
–
–
–
hemorrhage
infection
pulmonary embolism
myocardial infarction
Dartmouth-Hitchcock
Anesthetic Considerations
 Factors
influencing cardiovascular function
– direct effect of anesthetic agent on heart
– indirect effects mediated through the
autonomic nervous system
– level of ventilation
» hypoxia
» hypercarbia
» acidosis
Dartmouth-Hitchcock
Anesthetic Agents
 General
– inhalation
– intravenous
– muscle relaxants
 Spinal/Epidural
– hemodynamic
consideration
The skill & experience of the anesthesiologist,
including the ability to monitor hemodynamics &
respond quickly, are far more important than the
specific agent used.
Dartmouth-Hitchcock
Case Study





Fragilina Moribundi is a 93 yo, pleasantly demented
woman who presents to your office speaking fluent
diabinase. She is referred for pre-operative cardiac
evaluation prior to her planned cataract surgery.
She has a history of a systolic murmur, and is s/p IMI in
the distant past.
Her history is contributory only in the absence of sx’s
suggestive of active ischemia or LV dysfunction
Her exam is remarkable for findings c/w severe aortic
stenosis
Her EKG shows findings c/w OIMI
Dartmouth-Hitchcock
Case Study

Appropriate actions/evaluation would include
– stress testing with imaging to risk stratify and rule out active
ischemia
Dartmouth-Hitchcock
Case Study

Appropriate actions/evaluation would include
– stress testing with imaging to risk stratify and rule out active
ischemia
– echocardiography to evaluate the severity of the aortic stenosis
and baseline LV function
Dartmouth-Hitchcock
Case Study

Appropriate actions/evaluation would include
– stress testing with imaging to risk stratify and rule out active
ischemia
– echocardiography to evaluate the severity of the aortic stenosis
and baseline LV function
– cardiac catheterization with an eye towards balloon
valvuloplasty, if severe aortic stenosis is confirmed, as a bridge
to get her through the proposed surgery
Dartmouth-Hitchcock
Case Study

Appropriate actions/evaluation would include
– stress testing with imaging to risk stratify and rule out active
ischemia
– echocardiography to evaluate the severity of the aortic stenosis
and baseline LV function
– cardiac catheterization with an eye towards balloon valvuloplasty,
if severe aortic stenosis is confirmed, as a bridge to get her
through the proposed surgery
– a discussion with the PCP re: the indications for the proposed
surgery, and clearance for same with appropriate precautions
Dartmouth-Hitchcock
Case Study


Mrs. Moribundi does well with her cataract extraction, but
2 months later presents to the ER with evidence for total
bowel obstruction and free air under the diaphragm. You
are emergently consulted by the general surgeons who
want to take her to the OR.
Appropriate actions include:
– emergency echocardiogram to evaluate status of valve and
ventricle
Dartmouth-Hitchcock
Case Study


Mrs. Moribundi does well with her cataract extraction, but
2 months later presents to the ER with evidence for total
bowel obstruction and free air under the diaphragm. You
are emergently consulted by the general surgeons who
want to take her to the OR.
Appropriate actions include:
– emergency echocardiogram to evaluate status of valve and
ventricle
– trip to the cath lab for emergency balloon valvuloplasty
Dartmouth-Hitchcock
Case Study


Mrs. Moribundi does well with her cataract extraction, but
2 months later presents to the ER with evidence for total
bowel obstruction and free air under the diaphragm. You
are emergently consulted by the general surgeons who
want to take her to the OR.
Appropriate actions include:
– emergency echocardiogram to evaluate status of valve and
ventricle
– trip to the cath lab for emergency balloon valvuloplasty
– trip to the cath lab for IABP placement prior to surgery
Dartmouth-Hitchcock
Case Study


Mrs. Moribundi does well with her cataract extraction, but
2 months later presents to the ER with evidence for total
bowel obstruction and free air under the diaphragm. You
are emergently consulted by the general surgeons who
want to take her to the OR.
Appropriate actions include:
– emergency echocardiogram to evaluate status of valve and
ventricle
– trip to the cath lab for emergency balloon valvuloplasty
– trip to the cath lab for IABP placement prior to surgery
– discussion with anesthesia re: optimal peri-operative
management/hemodynamic monitoring
Dartmouth-Hitchcock
The Operation
 Type
– in general, surgical mortality is 25-50% higher in
patients with underlying cardiovascular conditions
compared to patients with normal cardiac function.
– ophthalmologic surgery & TURP almost always safe
– highest cardiovascular complication rates seen in
vascular surgery
» AAA

aortic cross-clamping, major fluid & electrolyte shifts
» carotid / peripheral surgery

co-existing CAD, clinical underestimation of severity
Dartmouth-Hitchcock
The Operation
 Duration
– correlation is general and mostly related to type
of operation
– exceptions
» operative time prolonged due to complication
» operation > 5 hours
Dartmouth-Hitchcock
Cardiac Risk for Noncardiac
Surgical Procedures
 High
–
–
–
–
(reported cardiac risk > 5%)
emergent major operations, esp. in elderly
aortic and other major vascular procedures
peripheral vascular procedures
anticipated prolonged procedure with large
fluid shift/blood loss
Dartmouth-Hitchcock
Cardiac Risk for Noncardiac
Surgical Procedures
 Intermediate
–
–
–
–
–
(reported cardiac risk < 5%)
carotid endarterectomy
head and neck
intraperitoneal & intrathoracic
orthopedic
prostate
Dartmouth-Hitchcock
Cardiac Risk for Noncardiac
Surgical Procedures
 Low
–
–
–
–
(reported cardiac risk < 1%)
endoscopic procedures
superficial procedure
cataract
breast
Dartmouth-Hitchcock
Case Study
 Mr. A.
Jean Jacques is a 58 year old
gentleman referred for pre-operative
evaluation because of one isolated PVC
seen on a pre-op EKG. He is scheduled for
nephrectomy for a renal mass the following
morning He has no cardiac history of
which he is aware. His only risk factor is
that of a history of 3 years of smoking in
college.
Dartmouth-Hitchcock
Case Study
 He
considers himself fit, and is proud of being in
good physical condition. He plays full court
basketball on Saturdays, and wins. He climbed
Mount Washington in October and was pleased
that a few of his sons friends could not keep up
with him. He denies dyspnea or chest discomfort,
and his exam is remarkable in that he looks fit and
has a resting pulse of 52 on no medications.
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– routine stress testing to risk stratify and rule out
occult ischemia
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– routine stress testing to risk stratify and rule out occult
ischemia
– 24 hour Holter monitor to evaluate burden of
ventricular ectopy
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– routine stress testing to risk stratify and rule out occult
ischemia
– 24 hour Holter monitor to evaluate burden of
ventricular ectopy
– echocardiogram to rule out unsuspected LV
dysfunction
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– routine stress testing to risk stratify and rule out occult
ischemia
– 24 hour Holter monitor to evaluate burden of
ventricular ectopy
– echocardiogram to rule out unsuspected LV
dysfunction
– clear for surgery with no recommendations for
further cardiac evaluation
Dartmouth-Hitchcock
Clinical Assessment
 History
– Single most important part of evaluation to
determine level of cardiovascular risk
» Identify presence of cardiac condition
» Evaluate severity, stability
» Identify risk factors, co-morbid conditions
» Determination of individual functional capacity
 Taking
a history for angina
Dartmouth-Hitchcock
The asymptomatic patient
 Silent
ischemia
– “active” silent ischemia
» Type I - absence of any sx despite the presence of
CAD & provocable ischemia (defective anginal
warning system)
» Type II - sx’s generally present, but patient also has
silent episodes
– “passive” silent ischemia
» sedentary patient
» patient limited for other reasons
Dartmouth-Hitchcock
Functional Capacity
1
MET
4
–
–
–
–
– Climb a flight of stairs, walk
up hill?
– Walk on level at 4 mph?
– Run a short distance?
– Heavy housework
– Golf, bowling, dancing,
doubles tennis
– Swimming, singles tennis
football, basketball, skiing
Can you take care of self?
Eat, dress, use toilet?
Walk indoors in house?
Walk a block or two on
level at 2-3 mph?
– Do light housework like
dusting or dishes?

METs
4 METs

>10 METs
Dartmouth-Hitchcock
Clinical Assessment
 Physical
–
–
–
–
examination
general appearance
evidence for CHF
evidence for PVD
heart sounds, murmur
Dartmouth-Hitchcock
Clinical Assessment
 Co-morbid
–
–
–
–
conditions
pulmonary
diabetes mellitus *
renal impairment
hematologic disorders
Dartmouth-Hitchcock
Clinical Assessment
 Ancillary
studies
– CBC, PT/PTT, blood chemistry (electrolytes, BUN,
creatinine)
– ECG
– CXR ??
Dartmouth-Hitchcock
Case Study

Alvin Falfa is a 63 yo dairy farmer from the Northeast
Kingdom. He was discharged from North Country
Hospital 3 weeks ago having sustained an uncomplicated,
non-Q MI. He has been slowly increasing his activity and
is asx. He was incidently found to have an iron deficiency
anemia during his hospitalization, and this was felt to be
the cause of his MI. Further w/u revealed a large,
fungating mass in his cecum, biopsy positive for adenoCa.
He is referred for pre-op evaluation prior to his right
hemicolectomy which is scheduled for tomorrow morning.
Dartmouth-Hitchcock
Case Study

Initial appropriate actions include:
– postponement of the scheduled surgery
Dartmouth-Hitchcock
Case Study

Initial appropriate actions include:
– postponement of the scheduled surgery
– stress testing for risk stratification and to determine whether
or not there is inducible ischemia
Dartmouth-Hitchcock
Case Study

Initial appropriate actions include:
– postponement of the scheduled surgery
– stress testing for risk stratification and to determine whether or not
there is inducible ischemia
– echocardiography to evaluate LV function
Dartmouth-Hitchcock
Case Study

Initial appropriate actions include:
– postponement of the scheduled surgery
– stress testing for risk stratification and to determine whether or not
there is inducible ischemia
– echocardiography to evaluate LV function
– cardiac catheterization with an eye towards intervention prior
to abdominal surgery
Dartmouth-Hitchcock
Case Study

Initial appropriate actions include:
– postponement of the scheduled surgery
– stress testing for risk stratification and to determine whether or not
there is inducible ischemia
– echocardiography to evaluate LV function
– cardiac catheterization with an eye towards intervention prior to
abdominal surgery
– clearance for surgery after a discussion with anesthesia about
appropriate peri-operative management/hemodynamic
monitoring
Dartmouth-Hitchcock
Clinical Predictors of Risk
 Major
– Unstable coronary syndromes
» recent MI with evidence for ischemia
» unstable or severe angina (Canadian class III or IV)
– Decompensated CHF
– Significant arrhythmia
» high grade AV block
» symptomatic ventricular arrhythmia (with organic disease)
» supraventricular arrhythmia with uncontrolled rate
– Severe valvular disease
Dartmouth-Hitchcock
Clinical Predictors of Risk
 Intermediate
–
–
–
–
–
Mild angina pectoris (Canadian class I or II)
Prior MI by history or pathological Q waves
Compensated or prior CHF
Diabetes mellitus
Renal insufficiency (creatinine > 2)
Dartmouth-Hitchcock
Clinical Predictors of Risk
 Minor
–
–
–
–
–
–
Advanced age
abnormal ECG (LVH, LBBB, ST-T change)
Rhythm other than sinus
Low functional capacity
History of stroke
Uncontrolled systemic hypertension
Dartmouth-Hitchcock
Determination of need for further
cardiac testing
 Urgency
of surgery
 Intermediate
predictor of
risk
 Recent
 Recent
 Major
– functional capacity
– risk level of surgery
revascularization
coronary evaluation
predictor of risk

Minor or no predictor of
risk
– functional capacity
– risk level of surgery
Dartmouth-Hitchcock
Disease-Specific Approaches
 Coronary Artery
Disease
 Hypertension
 Congestive
Heart Failure/Cardiomyopathy
 Valvular Heart Disease
 Arrhythmias & Conduction Defects
 Pulmonary Vascular Disease
Dartmouth-Hitchcock
Case Study
 Hiram
Wrisck is a 72 yo gentleman referred for
evaluation prior to AAA. He describes himself as
active, but his wife rolls her eyes behind his back
when he says this. He has a positive history of
hypertension and adult onset diabetes that recently
became insulin dependent, but no history to
suggest angina. A stress test done prior to his visit
with you demonstrated 1.5mm ST depression in
leads II, V4-6 at 4 METS (100 bpm)
Dartmouth-Hitchcock
Case Study
 Physical
exam shows him to be an obese 72
year old man looking older than his stated
age. He weighs 285#, pulse is 96 with
frequent extra-systoles, BP 140/90 in right
arm, 190/105 in left arm. The rest of the
exam is remarkable for a II/VI SEM at the
LSB, bilateral carotid and femoral bruits,
and absent pedal pulses.
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– Repeat stress as a DSE to try to get a heart rate
response closer to 85% PMHR
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– Repeat stress as a DSE to try to get a heart rate
response closer to 85% PMHR
– Cardiac catheterization with a low threshold for
percutaneous or surgical revascularization if
anatomically appropriate
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– Repeat stress as a DSE to try to get a heart rate
response closer to 85% PMHR
– Cardiac catheterization with a low threshold for
percutaneous or surgical revascularization if
anatomically appropriate
– Recommend intra-operative SG line and i.v. TNG
Dartmouth-Hitchcock
Case Study
 Appropriate
next steps include
– Repeat stress as a DSE to try to get a heart rate
response closer to 85% PMHR
– Cardiac catheterization with a low threshold for
percutaneous or surgical revascularization if
anatomically appropriate
– Recommend intra-operative SG line and i.v. TNG
– Fully review the medical record in hopes that Andy
Torkelson has previously seen him at some point in
time
Dartmouth-Hitchcock
Coronary Artery Disease
 Clinically
apparent vs occult disease
– past history
– active symptoms
– “active” vs “passive” silent ischemia
 Issues
to be addressed
– ischemic threshold
– amount of myocardium in jeopardy
– left ventricular function
Dartmouth-Hitchcock
Coronary Artery Disease
Risk assessment based on stress testing
 High
risk
– ischemia induced at low level (< 4 METs, heart
rate < 100 or < 70% age predicted) with:
» ST depression > 0.1 mV
» ST elevation > 0.1 mV in noninfarct lead
» five or more abnormal leads
» persistent ischemic response > 3 minutes post exercise
» typical angina
– thallium
Dartmouth-Hitchcock
Coronary Artery Disease
Risk assessment based on stress testing
 Intermediate
risk
– ischemia induced at moderate level (4-6 METs, heart
rate 100-130 or 70-85% age predicted with:
» ST depression > 0.1 mV
» typical angina
» persistent ischemic response >1-3 minutes post exercise
» three to four abnormal leads
Dartmouth-Hitchcock
Coronary Artery Disease
Risk assessment based on stress testing
 Low
risk
– no ischemia or ischemia at high level (> 7 METs,
heart rate > 130 or >85% age predicted with:
» ST depression > 0.1 mV
» typical angina
» one to two abnormal leads
Dartmouth-Hitchcock
Coronary Artery Disease
Indications for Coronary Angiography
 Class
I: patients with suspected or proven CAD
» high risk results from noninvasive testing
» angina pectoris refractory to medical therapy
» unstable angina
» nondiagnostic/equivocal test results in high risk pt.
 Class
II:
» intermediate risk results from noninvasive testing
» nondiagnostic/equivocal test results in intermediate risk pt.
» urgent non-cardiac surgery in convalescent period post-MI
» perioperative MI
Dartmouth-Hitchcock
Coronary Artery Disease
Indications for Coronary Angiography
 Class
III:
» low risk surgery in pt. with known CAD & low risk testing
» screening for CAD
» asx pt. after revascularization with exercise capacity > 7 METs
» mild, stable angina with good LV function, low risk testing
» patient not candidate for revascularization
Dartmouth-Hitchcock
Other disease states
 Hypertension
– not independent risk factor
– implications for intraoperative lability
– rational for preoperative control

Congestive heart failure/Cardiomyopathy
– confers risk independently
– etiology key to risk assessment/treatment
Dartmouth-Hitchcock
Other disease states
 Congestive
Heart Failure/Cardiomyopathy
» systolic vs diastolic dysfunction
» hypertrophic cardiomyopathy
 Valvular
heart disease
» aortic stenosis
» mitral stenosis
» regurgitant (volume overload) lesions
» antibiotic prophylaxis / anticoagulation
Dartmouth-Hitchcock
Other disease states
 Arrhythmias
& conduction defects
» important as markers for underlying disease
» therapy aimed to correct or avoid ischemia or
hemodynamic embarrassment
» high grade AV block - to pace or not to pace
 Pulmonary
vascular disease
» little objective data available
» sensitivity to hypoxia
» implication in presence of pre-existing shunts
Dartmouth-Hitchcock
Supplemental Preoperative Evaluation
 Resting
left ventricular function
» methodology
» when is it good to be over 40?
» indications for testing
 Stress
testing
» exercise
» nonexercise
persantine thallium
 dobutamine stress echocardiography

Dartmouth-Hitchcock
Preoperative Therapy
Surgical revascularization
 CASS
registry
Foster et al Ann Thorac Surg 1986;41:42-50
» 1600 pts. underwent noncardiac operations, 113 (7%) vascular
» mortality rates
0.5% without angiographic evidence advanced CAD
 0.9% with prior CABG
 2.4% with significant CAD (70% stenosis) but no prior revascularization

p=ns
p=.009
 European
Coronary Surgery Study Group Lancet 1982;2:1173-80
» survival rates, 58 pts. with PVD randomized to CABG or medical Rx
p=.02
85% with CABG
 57% with medical Rx

Dartmouth-Hitchcock
Preoperative Therapy
Surgical revascularization
 Cleveland
Clinic series Ann Surg. 1984;199:223-233
» 1001 pts. scheduled for elective vascular surgery
» mortality rates
5.3% + 1.5% for CABG group (6.8%)
 1.4% in group with normal coronaries
 1.8% in group with mild to moderate CAD
 3.6% in group with advanced, compensated CAD
 14% in group with severe, uncorrected CAD

» 5 year survival
72% in pts. who underwent CABG
 43% in pts. in whom CABG indicated but not performed

p=.001
Dartmouth-Hitchcock
Preoperative Therapy
Surgical revascularization
 Indications
–
–
–
–
for preoperative CABG
left main stenosis with acceptable risk
3VD with LV dysfunction
2VD with severe, proximal LAD disease
coronary ischemia refractory to medical
management
ACC/AHA Task Force JACC 1991;17:543-589
Dartmouth-Hitchcock
Preoperative Therapy
Catheter based revascularization
 Mayo
Clinic series
Mayo Clin Proc. 1992;67:15-21
» 50 pt. series, high risk group
10% required urgent CABG
 perioperative MI rate 5.6%
 mortality rate 1.9%

 Timing
» restenosis
» recoil/thrombosis
 New
technologies
Dartmouth-Hitchcock
Preoperative Therapy
Medical therapy
Author
Procedure
n
Control
Drug
Coriat
carotid
45
TNG 0.5
TNG 1.0
mcg/kg/m
mcg/kg/m
placebo
TNG 0.9
Anesth 1984
Dodds
noncardiac
45
Anesth Analg
1993
Godet
Anesth 1988
32%/30%
4%/0%
30
placebo
diltiazem
3mcg/kg/m
73%/4%
0/0
AAA
83
casecontrol
metoprolol
50 mg p.o.
_____
18%/3%
vascular
200
2.4/5
episodes
_____
noncardiac
128
Am J Surg
1989
Stone
0/0
vascular
Circ 1987
Pasternak
64%/17%
mcg/kg/m
Anesth 1987
Pasternak
Ischemia
MI
control/drug control/drug
unblinded metoprolol
50 mg p.o.
placebo
p.o. beta
blocker
28%/2%
0/0
Dartmouth-Hitchcock
Preoperative Therapy
 Valve
surgery
» general considerations
» balloon valvuloplasty
» stenotic vs regurgitant lesions
 Arrhythmia/Conduction
Devices
» ICD’s
» pacemakers
Dartmouth-Hitchcock
Tools Vs Toys
 Pulmonary
artery catheters
 Transesophageal
 Intra-aortic
echocardiography
balloon counterpulsation
Dartmouth-Hitchcock
Summary
Overview of ischemic
heart disease
 General
considerations

 Predictors
– Clinical
– Procedural

– Anesthetic
– Operative

Clinical assessment
of risk
Disease specific states
– CAD, hypertension,
CHF, valvular

Preoperative therapy
Dartmouth-Hitchcock
Conclusions
 Judgement/Experience/Skill
 Medical
care: a point in time vs continuum
 Teamwork
Dartmouth-Hitchcock
Dartmouth-Hitchcock