Preoperative cardiac risk assessment
For a printable checklist for pre-operative cardiac work up click here
To view the full Pre-operative clearance page click here

# Stepwise Approach to Pre-operative Cardiac Assessment
Adapted from Fleisher et al. Circulation. 2009 Nov 24;120(21):e169-276; 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. 

## Revised Cardiac Risk Index
- Identification of patients at high rate of complications who are undergoing elective cardiac surgery.
- Risk stratification with non invasive techniques.
- Rates of major cardiac complications increased with 2 or more risk factors of revised cardiac risk index.

## Surgery Specific Risk - 2007 ACC/AHA Guidelines
- Vascular surgery has a risk more than 5%
Aortic surgeries
Peripheral vascular surgery
- 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
- 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
- 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).
2. Decompensated HF
- NYHA functional class IV
- Worsening or new-onset heart failure
3. Significant Arrhythmias
- Mobitz II atrioventricular block
- Third degree AV block
- Symptomatic ventricular arrhythmias
- Supraventricular arrhythmias (including atrial fibrillation) with uncontrolled ventricular rate (HR greater than 100 bpm at rest)
- Symptomatic bradycardia
- Newly recognized ventricular tachycardia
4. Severe Valvular Disease
- Severe aortic stenosis (mean pressure gradient >40 mm Hg, aortic valve area <1.0 cm2, or symptomatic)
- Symptomatic mitral stenosis (progressive dyspnea on exertion, exertional presyncope, or heart failure)

# 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 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 O2kg-1min-1 or equivalently 1 kcalkg-1 h-1 or 4.184 kJkg-1 h-1. By convention 1 MET is considered as the resting metabolic rate obtained during quiet sitting . 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)

# Cardiac Risk Stratification for Non-cardiac Surgical Procedures

### High (Reported cardiac risk often greater than 5%)
- Aortic and other major vascular surgery.
- Peripheral vascular surgery.
- Anticipated prolonged surgical procedures associated with large fluid shifts and/or blood loss.

### Intermediate (Reported cardiac risk generally 1% to 5%)
- Carotid endarterectomy.
- Head and neck surgery.
- Intraperitoneal and intrathoracic surgery.
- Orthopedic surgery.
- Prostate surgery.

### Low (Reported cardiac risk generally less than 1%)
- Endoscopic procedures.
- Superficial procedure.
- Cataract surgery.
- Breast surgery.
- Ambulatory surgery.
- No Class I recommendation
- Class IIa recommendation in patients with
= 3 risk factors
Functional capacity of < 4 METs
High risk surgery (Vascular surgery)
- >= 3 risk factors
- Functional capacity of < 4 METs
- High risk surgery (Vascular surgery)

# 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
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.

# 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.
- 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 artery 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.

# Perioperative Revascularization Therapy
- Extensive ischemia is a risk factor for increased peri-operative events
- Pre-op coronary revascularization does not prevent death or MI. 

### 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. 
- The cumulative mortality and morbidity of both the coronary revascularization procedure and the noncardiac surgery should be weighed carefully. The individual patients overall health,functional status, and prognosis have to be taken into consideration. 

### Pre-operative PCI
- Prophylactic preoperative PCI in non cardiac surgical procedures is of no value in preventing perioperative cardiac events. 
- 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 in patients who have undergone successful coronary intervention with or without stent placement before planned or unplanned noncardiac surgery.

# 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.

## 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.

## 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.

## 2009 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Preoperative Cardiac Assessment (DO NOT EDIT)
Adapted from lecture of Robert B.McCully,M.D.;

# 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery

## Clinical Risk Factors

### Valvular Heart Disease

### Other clinical risk factors

## Approach to perioperative cardiac testing

### Multivariate risk indices

## Supplemental preoperative evaluation

### The 12-Lead Electrocardiogram

### Assessment of Left Ventricular Function

### Exercise Testing

### Noninvasive Pharmacological Stress Testing Before Noncardiac Surgery

### Preoperative Coronary Angiography

## Perioperative therapy

### Coronary Revascularization Before Noncardiac Surgery

### Timing of Elective Noncardiac Surgery in Patients With Previous PCI

### Perioperative Beta-Blocker Therapy

### Perioperative Statin Therapy

### Alpha-2 Agonists

### Angiotensin-Converting Enzyme Inhibitors

### Antiplatelet Agents

### Perioperative Management of Patients With CIEDs

## Anesthetic consideration and intraoperative management

### Choice of Anesthetic Technique and Agent

### Intraoperative Management

## Surveillance and management for perioperative MI

# 2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (DO NOT EDIT)

## Revascularization Before Noncardiac Surgery (DO NOT EDIT)

# Sources
- 2007 ACC/AHA Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery (DO NOT EDIT)
- 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 (DO NOT EDIT)
- 2011 ACCF/AHA/SCAI Guidelines for Percutaneous Coronary Intervention (DO NOT EDIT)