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Dartmouth-HitchcockDartmouth-Hitchcock
Preoperative Assessment of the Cardiac Patient for Non-cardiac Surgery
John R. Butterly, M.D.
Dartmouth-HitchcockDartmouth-Hitchcock
Issues Overview of ischemic
heart disease General
considerations– Anesthetic
– Operative
Clinical assessment
Predictors of risk– Clinical
– Procedural
Disease specific states– CAD, hypertension,
CHF, valvular
Preoperative therapy
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Overview of Ischemic Heart Disease
Anatomy Physiology
– coronary– left ventricular– patient
Dartmouth-HitchcockDartmouth-Hitchcock
Etiology of Ischemia
Supply– blood O2 carrying capacity
– cardiac output
– systemic vascular resistance
– coronary resistance (Poiseuille)
Demand– Major determinants of MVO2
» systolic work heart rate blood pressure (afterload) duration of systole
» ventricular wall tension (LaPlace)
» contractility
» myocardial mass
coronary resistance ~ 1/R4 T = PR
Dartmouth-HitchcockDartmouth-Hitchcock
Ischemia vs Infarction
Implications of demand related problem vs supply related problem– stability– biology
» endothelial function
» plaque rupture/thrombosis
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
General Considerations
Possible complications of anesthesia & surgery may impose additional burdens– hemorrhage– infection– pulmonary embolism– myocardial infarction
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Case Study Appropriate actions/evaluation would include
– stress testing with imaging to risk stratify and rule out active ischemia
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Cardiac Risk for Noncardiac Surgical Procedures
Intermediate (reported cardiac risk < 5%)– carotid endarterectomy– head and neck– intraperitoneal & intrathoracic– orthopedic– prostate
Dartmouth-HitchcockDartmouth-Hitchcock
Cardiac Risk for Noncardiac Surgical Procedures
Low (reported cardiac risk < 1%)– endoscopic procedures– superficial procedure– cataract– breast
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Case Study
Appropriate next steps include– routine stress testing to risk stratify and rule out
occult ischemia
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Functional Capacity
1 MET– 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?
4 METs
4 METs– 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
>10 METs
Dartmouth-HitchcockDartmouth-Hitchcock
Clinical Assessment
Physical examination– general appearance– evidence for CHF– evidence for PVD– heart sounds, murmur
Dartmouth-HitchcockDartmouth-Hitchcock
Clinical Assessment
Co-morbid conditions– pulmonary– diabetes mellitus *– renal impairment– hematologic disorders
Dartmouth-HitchcockDartmouth-Hitchcock
Clinical Assessment
Ancillary studies– CBC, PT/PTT, blood chemistry (electrolytes, BUN,
creatinine)– ECG– CXR ??
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Case Study Initial appropriate actions include:
– postponement of the scheduled surgery
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Determination of need for further cardiac testing
Urgency of surgery
Recent revascularization
Recent coronary evaluation
Major predictor of risk
Intermediate predictor of risk– functional capacity
– risk level of surgery
Minor or no predictor of risk– functional capacity
– risk level of surgery
Dartmouth-HitchcockDartmouth-Hitchcock
Disease-Specific Approaches
Coronary Artery Disease Hypertension Congestive Heart Failure/Cardiomyopathy Valvular Heart Disease Arrhythmias & Conduction Defects Pulmonary Vascular Disease
Dartmouth-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-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-HitchcockDartmouth-Hitchcock
Preoperative TherapySurgical 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
European Coronary Surgery Study Group Lancet 1982;2:1173-80
» survival rates, 58 pts. with PVD randomized to CABG or medical Rx 85% with CABG 57% with medical Rx
p=.009
p=.02
p=ns
Dartmouth-HitchcockDartmouth-Hitchcock
Preoperative TherapySurgical 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-HitchcockDartmouth-Hitchcock
Preoperative TherapySurgical 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-HitchcockDartmouth-Hitchcock
Preoperative TherapyCatheter 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-HitchcockDartmouth-Hitchcock
Preoperative TherapyMedical therapy
Author Procedure n Control Drug Ischemiacontrol/drug
MIcontrol/drug
CoriatAnesth 1984
carotid 45 TNG 0.5mcg/kg/m
TNG 1.0mcg/kg/m
64%/17% 0/0
DoddsAnesth Analg
1993
noncardiac 45 placebo TNG 0.9mcg/kg/m
32%/30% 4%/0%
GodetAnesth 1987
vascular 30 placebo diltiazem3mcg/kg/m
73%/4% 0/0
PasternakCirc 1987
AAA 83 case-control
metoprolol50 mg p.o.
_____ 18%/3%
PasternakAm J Surg
1989
vascular 200 unblinded metoprolol50 mg p.o.
2.4/5episodes
_____
StoneAnesth 1988
noncardiac 128 placebo p.o. betablocker
28%/2% 0/0
Dartmouth-HitchcockDartmouth-Hitchcock
Preoperative Therapy
Valve surgery» general considerations
» balloon valvuloplasty
» stenotic vs regurgitant lesions
Arrhythmia/Conduction Devices» ICD’s
» pacemakers
Dartmouth-HitchcockDartmouth-Hitchcock
Tools Vs Toys
Pulmonary artery catheters
Transesophageal echocardiography
Intra-aortic balloon counterpulsation
Dartmouth-HitchcockDartmouth-Hitchcock
Summary Overview of ischemic
heart disease General
considerations– Anesthetic
– Operative
Clinical assessment
Predictors of risk– Clinical
– Procedural
Disease specific states– CAD, hypertension,
CHF, valvular
Preoperative therapy
Dartmouth-HitchcockDartmouth-Hitchcock
Conclusions
Judgement/Experience/Skill
Medical care: a point in time vs continuum
Teamwork
Dartmouth-HitchcockDartmouth-Hitchcock