Stepwise Approach to Pre-operative Cardiac Assessment
Adapted from Fleisher et al. Circulation. 2009 Nov 24;120(21):e169-276[1]; HR, Heart rate
§,∧ Noninvasive testing is not useful for patients with no clinical risk factors undergoing intermediate-risk or low-risk noncardiac surgery (AHA guidelines Class III, Level of Evidence: C).
¶Clinical risk factors: Ischemic heart disease, compensated or prior heart failure, diabetes mellitus, renal insufficiency, and cerebrovascular disease
Cardiac Risk Index
Original / Goldman Index
Goldman et.al devised a cardiac index for preoperative evaluation in 1977. [2]
Risk Factors
Points
History
Age > 70 years
5
Recent MI (6 months)
10
Aortic Stenosis
3
Physical Examination
Signs of Chronic Heart Failure
11
Electrocardiogram
Rhythm other than Sinus Rhythm
7
PVC's > 5/ min
7
Poor General Medical Condition
PO2 < 60mmHg; PCO2 > 50mmHg; K < 3mmol/l; HCO3 < 20mmol/l; urea >18mmol/l (BUN > 50mg/dl); Creatinine > 260umol/l (3mg/dl); bedridden from non-cardiac cause
3
Surgery
Emergency
4
Intrathoracic
3
Total Points
53
Goldman
Classification
Total
Points
1
0 - 5
2
6 - 12
3
13 - 25
4
> 25
Revised Cardiac Risk Index
Identification of patients at high rate of complications who are undergoing elective cardiac surgery.
Risk stratification with non invasive techniques.[3]
Revised Cardiac Risk Index
1. History of Ischemic Heart Disease
2. History of Congestive Heart Failure
3. History of Cerebrovascular Disease
4. Insulin Therapy for Diabetes
5. Renal Insufficiency
6. High Risk Type Surgery
Rates of major cardiac complications increased with 2 or more risk factors of revised cardiac risk index.[3]
Surgery Specific Risk - 2007 ACC/AHA guidelines
Vascular surgery has a risk more than 5%
Aortic surgeries
Peripheral vascular surgery
Intermediate risk surgeries are as follows:(1- 5% risk)
Intraperitoneal
Intrathoracic
Carotid endarterectomy
Head and neck surgery
Orthopedic surgery
Prostate surgery
Low risk:(< 1%)
Endoscopic procedures
Superficial procedures
Cataract surgery
Breast surgery
Ambulatory surgery
Cardiac Conditions with Increased Pre-operative Risk
1. Unstable Coronary Syndromes
Unstable or severe angina (Canadian Cardiovascular Society class III or IV): May include “stable” angina in patients who are unusually sedentary.
Recent MI: Greater than 7 days, but less than or equal to 1 month (within 30 days)
Estimated Energy Requirements for Various Activities
The metabolic equivalent of task (MET), or simply metabolic equivalent, is a physiological concept expressing the energy cost of physical activities[4] as multiples of resting metabolic rate (RMR) and is defined as the ratio of metabolic rate (and therefore the rate of energy consumption) during a specific physical activity to a reference rate of metabolic rate at rest, set by convention to 3.5 ml O2·kg-1·min-1 or equivalently 1 kcal·kg-1· h-1 or 4.184 kJ·kg-1· h-1. By convention 1 MET is considered as the resting metabolic rate obtained during quiet sitting[5][6] . MET values of physical activities range from 0.9 (sleeping) to 18 (running at 17.5 km/h or a 5:31 mile pace).
Calculating the Weekly Energy Expended in Recreational-time Physical Activity using METs (Metabolic equivalent task) [7].
Physical Activity
MET
Light Intensity Activities
< 3
Sleeping
0.9
Watching television
1.0
Writing, desk work, typing
1.8
Walking, 1.7 mph (2.7 km/h), level ground, strolling, very slow
2.3
Walking, 2.5 mph (4 km/h)
2.9
Moderate Intensity Activities
3 to 6
Bicycling, stationary, 50 watts, very light effort
3.0
Walking 3.0 mph (4.8 km/h)
3.3
Calisthenics, home exercise, light or moderate effort, general
3.5
Walking 3.4 mph (5.5 km/h)
3.6
Bicycling, <10 mph (16 km/h), leisure, to work or for pleasure
1.Patients who have a need for emergency noncardiac surgery should proceed to the operating room and continue perioperative surveillance and postoperative risk :stratification and risk factor management. (Level of Evidence: C)
2.Patients with active cardiac conditions* should be evaluated and treated per ACC/AHA guidelines and, if appropriate, consider proceeding to the operating room. (Level of Evidence: B)
3.Patients undergoing low risk surgery are recommended to proceed to planned surgery.† (Level of Evidence: B)
4.Patients with poor (less than 4 METs) or unknown functional capacity and no clinical risk factors should proceed with planned surgery.† (Level of Evidence: B)
1.It is probably recommended that patients with functional capacity greater than or equal to 4 METs without symptoms‡ proceed to planned surgery.§ (Level of Evidence: B)
2.It is probably recommended that patients with poor (less than 4 METs) or unknown functional capacity and 3 or more clinical risk factors who are scheduled for vascular surgery consider testing if it will change management.¶ (Level of Evidence: B)
3.It is probably recommended that patients with poor (less than 4 METs) or unknown functional capacity and 3 or more clinical risk factors who are scheduled for intermediate risk surgery proceed with planned surgery with heart rate control.¶ (Level of Evidence: B)
4.It is probably recommended that patients with poor (less than 4 METs) or unknown functional capacity and 1 or 2 clinical risk factors who are scheduled for vascular or intermediate risk surgery proceed with planned surgery with heart rate control.¶ (Level of Evidence: B)
1.Noninvasive testing might be considered if it will change management for patients with poor (less than 4 METs) or unknown functional capacity and 3 or more clinical risk factors who are scheduled for intermediate risk surgery. (Level of Evidence: B)
2.Noninvasive testing might be considered if it will change management for patients with poor (less than 4 METs) or unknown functional capacity and 1 or 2 clinical risk factors who are scheduled for vascular or intermediate risk surgery. (Level of Evidence: B)
§Noninvasive testing may be considered before surgery in specific patients with risk factors if it will change management. Clinical risk factors include ischemic heart disease, compensated or prior heart failure, diabetes mellitus, renal insufficiency, and cerebrovascular disease. ¶Consider perioperative beta blockade for populations in which this has been shown to reduce cardiac morbidity/mortality.
Key points about NST
No Class I recommendation
Class IIa recommendation in patients with
>= 3 risk factors
Functional capacity of < 4 METs
High risk surgery (Vascular surgery)
2007 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Recommendations for Non-invasive Evaluation of Left Ventricular Function [8] (DO NOT EDIT)
1.It is reasonable for patients with dyspnea of unknown origin to undergo preoperative evaluation of left ventricular (LV) function. (Level of Evidence: C)
2.It is reasonable for patients with current or prior heart failure with worsening dyspnea or other change in clinical status to undergo preoperative evaluation of LV function if not performed within 12 months (Level of Evidence: C)
1. Reassessment of LV function in clinically stable patients with previously documented cardiomyopathy is not well established. (Level of Evidence: C)
Pre-operative Stress Testing
For patients who are able to exercise : Treadmill Exercise ECG.
For patients who are unable to exercise : Pharmacological Stress Imaging.
Electrocardiogram - Treadmill Exercise ECG
Risk Assessment
Risk
METs
Heart rate
High Risk - Ischemia induced by low level of exercise
< 4
< 100 or 70% age pred. max
Intermediate Risk - Ischemia induced by moderate exercise
4 - 6
> 100 - 130 or 70 - 85% of age pred. max
Low Risk - No ischemia or ischemia induced at higher level of exercise
> 7
> 130 or > 85% of age pred. max
Inadequate test : In patients undergoing non cardiac surgery ,the inabilty to exercise to a level of 4 - 6 METs without out ischemia should be considered as inadequate test. (Stage II Bruce protocol)
Pre-operative 12 Lead ECG
The time frame for ECG testing is fixed, it can be done within 30 days of planned surgery when indicated.
The resting 12-lead ECG did not identify increased perioperative risk in patients undergoing low-risk surgery.
In patients with coronary disease, the resting 12-lead ECG may have contains important prognostic information relating to long-term morbidity and mortality.
2007 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Recommendations for Preoperative Resting 12 - Lead ECG[8] (DO NOT EDIT)
1. Preoperative resting 12-lead ECG is recommended for patients with at least 1 clinical risk factor who are undergoing vascular surgical procedures. (Level of Evidence: B)
2. Preoperative resting 12-lead ECG is recommended for patients with known CHD, peripheral arterial disease, or cerebrovascular disease who are undergoing intermediate-risk surgical procedures. (Level of Evidence: C)
1. Preoperative and postoperative resting 12-lead ECGs are not indicated in asymptomatic persons undergoing low-risk surgical procedures. (Level of Evidence: B)
1. Preoperative resting 12-lead ECG is reasonable in persons with no clinical risk factors who are undergoing vascular surgical procedures. (Level of Evidence: B)
1. . Preoperative resting 12-lead ECG may be reasonable in patients with at least 1 clinical risk factor who are undergoing intermediate-risk operative procedures. (Level of Evidence: B)
Non invasive Stress Testing (NST)
These are used for preoperative evaluation of patients undergoing non cardiac surgery. These are used in patients who cannot exercise.
Techniques
Increasing oxygen demand of the heart either by pacing or inotropes
Increasing blood supply (hyperemic response) by vasodilators
Dobutamine Stress Echocardiography
Increasing doses of supratherapeutic doses of dobutamine are infused , which increases myocardial contractility and heart rate. This leads to significant coronary stenosis which can be identified by regional wall-motion abnormalities within the distribution of the affected vessels.
It has high negative predictive value (93-100%)
It has low positive predicitive value (5 - 33%)
Extent of regional wall motion abnormality and low threshold of ischemia is an important predictor of post operative events.
Radionuclide Myocardial Perfusion Imaging
Stress nuclear myocardial perfusion imaging has a high sensitivity for detecting patients at risk for perioperative cardiac events.
It has high negative predictive value (95-100%)
It has low positive predictive value (5- 20%)
Perioperative cardiac risk is directly proportional to the myocardium at risk detected by the extent of reversible defects found on imaging.
It is of high clinical value when used for selective population of high clinical risk.
In Left Bundle-Branch Block
Exercise may at times induce reversible septal defects in the absence of LAD disease. Specificity of exercise myocardial perfusion imaging in presence of LBBB is low.
Pharmacologic strss testing with perfusion scintigraphy or DSE is preferred over exercise stress testing.
2007 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Noninvasive Stress Testing Before Noncardiac Surgery[8] (DO NOT EDIT)
1. Patients with active cardiac conditions (see Table 2) in whom noncardiac surgery is planned should be evaluated and treated per ACC/AHA guidelines before noncardiac surgery. (Level of Evidence: B)
1. Noninvasive testing is not useful for patients with no clinical risk factors undergoing intermediate-risk noncardiac surgery. (Level of Evidence: C)
2. Noninvasive testing is not useful for patients undergoing low-risk noncardiac surgery. (Level of Evidence: C)
1. Noninvasive stress testing of patients with 3 or more clinical risk factors and poor functional capacity (less than 4 METs) who require vascular surgery is reasonable if it will change management. (Level of Evidence: B)
1. Noninvasive stress testing may be considered for patients with at least 1 to 2 clinical risk factors and poor functional capacity (less than 4 METs) who require intermediate-risk noncardiac surgery if it will change management. (Level of Evidence: B)
2. Noninvasive stress testing may be considered for patients with at least 1 to 2 clinical risk factors and good functional capacity (greater than or equal to 4 METs) who are undergoing vascular surgery. (Level of Evidence: B)
1.Routine prophylactic coronary revascularization is not recommended.
Extensive ischemia is a risk factor for increased peri-operative events
Pre-op coronary revascularization does not prevent death or MI. [9]
Pre-operative CABG
Patients who have high-risk coronary anatomy and in whom long-term outcome would likely be improved by CABG should generally undergo coronary revascularization before a noncardiac elective vascular surgical procedure or noncardiac operative procedures of intermediate or high risk. [10]
The cumulative mortality and morbidity of both the coronary revascularization procedure and the noncardiac surgery should be weighed carefully. The individual patient’s overall health,functional status, and prognosis have to be taken into consideration. [11]
Pre-operative PCI
Prophylactic preoperative PCI in non cardiac surgical procedures is of no value in preventing perioperative cardiac events. [12]
Unscheduled noncardiac surgery in a patient who has undergone a prior PCI presents special challenges, particularly with regard to management of the dual-antiplatelet agents required in those who have received coronary stents.
Following flowchart depicts the approach based on expert opinion[13] in patients who have undergone successful coronary intervention with or without stent placement before planned or unplanned noncardiac surgery.
Prior PCI
Balloon Angioplasty
Bare Metal Stent
Drug
Time since PCI < 14 days
Time since PCI > 14 days
Time since PCI > 30-45 days
Time since PCI < 30-45 days
Time since PCI < 365 days
Time since PCI > 365 days
Delay for elective surgery
Proceed to operating room with aspirin
Delay for elective surgery
Proceed to operating room with aspirin
2011 ACC/AHA Guidelines for Percutaneous Coronary Intervention: Revascularization Before Non-cardiac Surgery[14](DO NOT EDIT)
" 1. Coronary revascularization before noncardiac surgery is useful in patients with stable angina who have significant left main coronary artery stenosis (Level of Evidence: A) "
" 2. Coronary revascularization before noncardiac surgery is useful in patients with stable angina who have 3-vessel disease. (Survival benefit is greater when left ventricular ejection fraction is less than 0.50.) (Level of Evidence: A) "
" 3. Coronary revascularization before noncardiac surgery is useful in patients with stable angina who have 2-vessel disease with significant proximal left anterior descending stenosis and either ejection fraction less than 0.50 or demonstrable ischemia on noninvasive testing (Level of Evidence: A) "
" 4. Coronary revascularization before noncardiac surgery is recommended for patients with high-risk unstable angina or non–ST-segment elevation myocardial infarction (MI) (Level of Evidence: A) "
" 5. Coronary revascularization before noncardiac surgery is recommended in patients with acute STelevation MI.(Level of Evidence: A) "
" 1. The usefulness of preoperative coronary revascularization is not well established in high-risk ischemic patients (eg, abnormal dobutamine stress echocardiogram with at least 5 segments of wall-motion abnormalities) (Level of Evidence: C) "
" 2. The usefulness of preoperative coronary revascularization is not well established for low-risk ischemic patients with an abnormal dobutamine stress echocardiogram (segments 1 to 4).(Level of Evidence: B) "
Perioperative Medical Therapy
Beta Blockers
Key points about perioperative beta blocker therapy
Start well before surgery. ( minimum of 1 week - don't start on the day of surgery)
Use is in high or intermediate risk population only.
Titrate dose to heart rate and blood pressure starting with a low dose. (Fixed doses shouldn't be used)
Long acting betablockers are better to use.
If intra-operative heat rate goes above 80 start IV administration.(Look for alternative causes of tachycardia)
For more information on perioperative betablocker therapy click here.
2009 ACC/AHA Guidelines - Focused Update on Recommendations for Perioperative Beta Blockade[26] (DO NOT EDIT)
1. Titrate beta blocker to heart rate, blood pressure in patients undergoing vascular(high risk) or intermediate risk surgery who are at high risk(CAD, >= 2 risk factors).
2007 ACC/AHA Guidelines - Recommendations for Perioperative Beta Blockade [8] (DO NOT EDIT)
1. Beta blockers should be given to patients undergoing vascular surgery who are at high cardiac risk owing to the finding of ischemia on preoperative testing.(Level of Evidence: B)
1. Beta blockers are probably recommended for patients undergoing vascular surgery in whom preoperative assessment identifies coronary heart disease.(Level of Evidence: B)
2. Beta blockers are probably recommended for patients in whom preoperative assessment for vascular
surgery identifies high cardiac risk, as defined by the presence of more than 1 clinical risk factor.(Level of Evidence: B)
3. Beta blockers are probably recommended for patients in whom preoperative assessment identifies coronary heart disease or high cardiac risk, as defined by the presence of more than 1 clinical risk factor, who are undergoing intermediate-risk or vascular surgery.(Level of Evidence: B)
1.The usefulness of beta blockers is uncertain for patients who are undergoing either intermediate risk procedures or vascular surgery, in whom preoperative assessment identifies a single clinical risk factor.(Level of Evidence: C)
2.The usefulness of beta blockers is uncertain in patients undergoing vascular surgery with no clinical risk factors who are not currently taking beta blockers (Level of Evidence: B)
Statins
Statins have protective effective on cardiac complications in non cardiac surgery, but the dosage and the target levels are unclear.
Utilizing the perioperative period as an opportunity to impact long-term health, consideration should be given to starting statin therapy in
patients who meet National Cholesterol Education Program criteria.
2007 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Recommendations for Statin Therapy[13] (DO NOT EDIT)
" 1. For patients with at least 1 clinical risk factor who are undergoing intermediate-risk procedures, statins may be considered. (Level of Evidence: C) "
Alpha 2 Agonists
Strong evidence is lacking for the recommendation of clonidine for blood pressure control.
Administration of clonidine had minimal effects on hemodynamics and post operative mortality.
2007 ACC / AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Alpha- 2 agonists[13] (DO NOT EDIT)
"1. Alpha-2 agonists for perioperative control of hypertension may be considered for patients with known CAD or at least 1 clinical risk factor who are undergoing surgery. (Level of Evidence: A) "
2007 ACC / AHA Guidelines - Recommendations for Preoperative Intensive care monitoring [13] (DO NOT EDIT)
"1. Preoperative intensive care monitoring with a pulmonary artery catheter for optimization of hemodynamic status might be considered; however, it is rarely required and should be restricted to a very small number of highly selected patients whose presentation is unstable and who have multiple comorbid conditions (Level of Evidence: B) "
2007 ACC / AHA Guidelines - Recommendations for use of volatile anesthetic agents [13] (DO NOT EDIT)
"1.It can be beneficial to use volatile anesthetic agents during noncardiac surgery for the maintenance of general anesthesia in hemodynamically stable patients at risk for myocardial ischemia. (Level of Evidence: B) "
2007 ACC / AHA Guidelines - Recommendations for Prophylactic Intraoperative Nitroglycerine [13] (DO NOT EDIT)
"1. The usefulness of intraoperative nitroglycerin as a prophylactic agent to prevent myocardial ischemia and cardiac morbidity is unclear for high-risk patients undergoing noncardiac surgery, particularly those who have required nitrate therapy to control angina. The recommendation for prophylactic use of nitroglycerin must take into account the anesthetic plan and patient hemodynamics and must recognize that vasodilation and hypovolemia can readily occur during anesthesia and surgery(Level of Evidence: C) "
2007 ACC / AHA Guidelines - Recommendations for Use of Transesophageal Echocardiography [13] (DO NOT EDIT)
"1.The emergency use of intraoperative or perioperative transesophageal echocardiography is reasonable to determine the cause of an acute, persistent, and life-threatening hemodynamic abnormality (Level of Evidence: C) "
2007 ACC / AHA Guidelines - Recommendations for maintenance of body temperature [13] (DO NOT EDIT)
" 1.. Maintenance of body temperature in a normothermic range is recommended for most procedures
other than during periods in which mild hypothermia is intended to provide organ protection (eg, during high aortic cross-clamping).(Level of Evidence: B) "
2007 ACC / AHA Guidelines - Recommendations for Perioperative control of blood glucose concentration [13] (DO NOT EDIT)
"1.It is reasonable that blood glucose concentration be controlled during the perioperative period in patients with diabetes mellitus or acute hyperglycemia who are at high risk for myocardial ischemia or who are undergoing vascular and major noncardiac surgical procedures with planned intensive care unit admission (Level of Evidence: B) "
"1.The usefulness of strict control of blood glucose concentration>> during the perioperative period is uncertain in patients with diabetes mellitus or acute hyperglycemia who are undergoing noncardiac surgical procedures without planned intensive care unit admission (Level of Evidence: C) "
2007 ACC / AHA Guidelines - Recommendations for Perioperative use of Pulmonary artery catheters [13] (DO NOT EDIT)
" 1. Routine use of a pulmonary artery catheter perioperatively, especially in patients at low risk of developing hemodynamic disturbances, is not recommended (Level of Evidence: A) "
"1.Use of a pulmonary artery catheter may be reasonable in patients at risk for major hemodynamic disturbances that are easily detected by a pulmonary artery catheter; however, the decision must be based on 3 parameters: patient disease, surgical procedure (ie, intraoperative and postoperative fluid shifts), and practice setting (experience in pulmonary artery catheter use and interpretation of results), because incorrect interpretation of the data from a pulmonary artery catheter may cause harm (Level of Evidence: B) "
2007 ACC / AHA Guidelines - Recommendations for Intraoperative and postoperative ST segment monitoring [13] (DO NOT EDIT)
"1.Intraoperative and postoperative ST-segment monitoring can be useful to monitor patients with known CAD or those undergoing vascular surgery, with computerized ST-segment analysis, when available, used to detect myocardial ischemia during the perioperative period (Level of Evidence: B) "
"1.Intraoperative and postoperative ST-segment monitoring may be considered in patients with single or multiple risk factors for CAD who are undergoing noncardiac surgery (Level of Evidence: B) "
2007 ACC / AHA Guidelines - Recommendations for Surveillance for Perioperative MI[13](DO NOT EDIT)
" 1. Postoperative troponin measurement is recommended in patients with ECG changes or chest pain typical of acute coronary syndrome.(Level of Evidence: C) "
"1.The use of postoperative troponin measurement is not well established in patients who are clinically stable and have undergone vascular and intermediate-risk surgery (Level of Evidence: C) "
References
↑Fleisher LA, Beckman JA, Brown KA; et al. (2009). "2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American college of cardiology foundation/American heart association task force on practice guidelines". Circulation. 120 (21): e169–276. doi:10.1161/CIRCULATIONAHA.109.192690. PMID19884473. Unknown parameter |month= ignored (help)CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
↑Physical activity can be defined as “bodily movement produced by the contraction of skeletal muscle that increases energy expenditure above the basal level”
↑Adapted from Compendium of Physical Activities. Ainsworth, BE et al. Medicine and Science in Sports and Exercise. Vol 25, Pg 713 (1993) and Vol 32, S498 (2000).
↑"Guidelines and indications for coronary artery bypass graft surgery. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Subcommittee on Coronary Artery Bypass Graft Surgery)". Journal of the American College of Cardiology. 17 (3): 543–89. 1991. PMID1993774. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
