A preoperative cardiac assessment involves evaluating a patient’s cardiovascular risk before undergoing noncardiac surgery.
Preoperative risk cardiac risk assessment focuses on history and physical exam to identify unstable or undiagnosed cardiac conditions, estimate the risk of major adverse cardiac events and determine who may benefit from additional testing or revascularization prior to surgery.
Major adverse cardiac events are common causes of perioperative mortality and major morbidity.
Preventing these complications requires thorough preoperative risk assessment and postoperative monitoring of at-risk patients.
1. 12-lead ECG: A preoperative resting 12-lead ECG is reasonable for patients with known coronary heart disease or other significant structural heart disease, except for those undergoing low-risk surgery.
It may also be considered for asymptomatic patients, except for low-risk surgery
Routine ECG is not recommended for asymptomatic patients undergoing low-risk procedures.
2. Assessment of Left Ventricular (LV) Function: Evaluating LV function in patients with dyspnea of unknown origin or in those with heart failure (HF) with worsening symptoms or a change in clinical status is recommended..
Routine evaluation of LV function in clinically stable patients is not recommended.
3. Exercise Stress Testing. For patients with elevated risk and excellent functional capacity, it is reasonable to proceed to surgery without further testing.
For those with elevated risk and unknown functional capacity, exercise testing may be considered if it will change management.
Routine screening with noninvasive stress testing is not useful for low-risk noncardiac surgery.
4. Noninvasive Pharmacological Stress Testing: For patients at elevated risk with poor functional capacity, dobutamine stress echocardiography (DSE) or myocardial perfusion imaging (MPI) may be reasonable if it will change management
Major perioperative cardiac guidelines recommend beginning preoperative cardiac risk assessment with a focused history and physical exam to identify unstable or undiagnosed cardiac conditions, estimate the risk of major adverse cardiac events and determine who may benefit from additional testing or revascularization prior to surgery.
Assessments of surgical urgency, clinical assessment for acute coronary syndrome, and estimation of combined medical and surgical cardiac risk using a validated cardiac risk assessment instrument.
Patients with an estimated risk of MACE < 1% (low risk) can proceed to surgery without further testing.
The assessment of functional capacity in metabolic equivalents (METs) is recommended for patients with an estimated cardiac risk of greater than or equal to 1% (elevated risk).
Patients with elevated cardiac risk who have a poor or unknown functional capacity (<4 METs) can be further risk stratified with pharmacologic stress testing.
With preoperative ssessment management changes might include changes in operative plans, changes in pharmacotherapy, or rarely, coronary revascularization.
Patients with a normal stress test can proceed to surgery, whereas those with an abnormal stress test should be managed according to existing clinical practice guidelines.
The initial step is an assessment of surgical urgency, with a recommendation to proceed to surgery if the need is urgent.
Patients undergoing elective surgery should be assessed for active or unstable cardiac conditions.
Surgical risk is assessed according to low (<1%), intermediate (1%-5%), and high (>5%) risk categories.
Patients undergoing low-risk surgical procedures can proceed to surgery without additional testing.
Patients undergoing intermediate or high-risk surgeries should have their functional capacity in METs assessed.
Patients with a functional capacity greater than 4 METs can proceed to surgery.
If the functional capacity is less than 4 METs, or cannot be determined, clinical risk can be assessed using the Gupta MICA calculator.
The surgical urgency should be evaluated first, as there are distinct pathways for emergent, urgent, semiurgent, and elective surgery.
Patients with emergent surgical needs should proceed to surgery without further cardiac assessment.
Postoperative monitoring with troponins and electrocardiography and comanagement by a medical specialist is recommended if the patient is older than 64 years or has known significant cardiovascular disease.
Patients with urgent or semiurgent surgical need should proceed to surgery, with preoperative cardiac assessment only if there is an unstable cardiac condition, suspicion of severe valvular heart disease or evidence of severe pulmonary hypertension.
Patients who are age 65 years or older, are 45 to 64 years old with significant cardiovascular disease, or have an RCRI score of 1 or greater are recommended to have brain natriuretic peptide (BNP) or N-terminal pro-brain natriuretic peptide (NT-proBNP) testing to further stratify risk.
Postoperative monitoring is not recommended for patients with normal preoperative natriuretic peptide levels.
It is recommended to consider stress testing for patients with elevated risk (>1%) and poor functional capacity (<4 METs).
If BNP levels are elevated, postoperative troponin monitoring, rather than preoperative stress testing, is recommended.
The ACC/AHA guideline uses a combined patient- and surgery-specific risk, with 2 risk categories: low (<1%) and elevated (≥1%) risk.
Elevated risk: Patients age 45 years and older, or patients with known cardiovascular disease, have a 1% or greater risk of perioperative MACE.
The universal screening studies have identified that the majority of patients with postoperative ischemia were asymptomatic (65%).
Guidelines for Preoperative Cardiac Testing
Electrocardiogram Used in patients with known CVD, except in low-risk surgery. Used to establish baseline and discover underlying CVD in asymptomatic individuals, except in low-risk surgery.
Used postoperatively in those with signs or symptoms of MI
Used in those who have CVD risk factors or are undergoing high-risk (>5%) surgery
Echocardiogram
Used in those who have unexplained dyspnea, a history of heart failure with a change in clinical status or no assessment in the last year, or are undergoing high-risk surgery (> 1%).
Not recommended testing
Stress testing Considered in those who are undergoing elevated-risk surgery (≥1%) and unknown or low functional capacity of <4 METs). Angiogram Same uses as nonoperative indications
BNP or NT-proBNP Used for diagnosing heart failure or assessing optimization of heart failure patients.
Used as additional independent prognostic information for perioperative and late cardiac events in high-risk patients (RCRI >1 for vascular surgery, RCRI >2 for other surgeries).
BNP or NT-proBNP is strongly recommend before noncardiac surgery that will require at least one overnight stay in the hospital in patients who are >65 years old, are 45-64 years old with significant CVD, or have RCRI score ≥
Troponin analysis is used postoperatively in those with signs or symptoms of MI, and used in high-risk patients both before and 48-72 hours after major surgery.
Troponin analysis is used in patients >65 years old or age 18-64 with significant CVD or a positive BNP or NT-proBNP or in those who would have qualified for BNP or NT-proBNP but were unable to have the test performed.
RCRI risk factors: high-risk type of surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, preoperative treatment with insulin, and preoperative serum creatinine >2.0 mg/dL.
Cardiac Risk Calculators
The calculators recommended by current guidelines use patient and procedural factors to estimate the risk of MACE after surgery.
The most widely validated risk prediction tool is the RCRI.
The variables that determined risk of adverse cardiac surgical outcomes were (1) high-risk surgery, (2) history of ischemic heart disease, (3) history of CHF, (4) creatinine greater than 2 mg/dL, (5) cerebrovascular disease, and (6) diabetes requiring insulin.
Patients with increasing numbers of these variables had a higher risk for postoperative adverse cardiac outcomes.
The adverse outcomes measured were MI, ventricular fibrillation or cardiac arrest, complete heart block or pulmonary edema.
Studies have shown only moderate correlation with adverse cardiac events at intermediate functional capacity (4 to 10 METs).
Poor functional capacity (<4 METs), owing to noncardiac limitations, might have a stronger correlation with noncardiac complications such as prolonged intubation or infection; this might reflect the importance of pulmonary function and general health status on overall perioperative risk.
Poor functional capacity owing to cardiac limitations is associated with an increase in cardiac and noncardiac risk.
Excellent functional capacity (>10 METs) is associated with a low risk of cardiac complications, even in the setting of major risk factors.
There is a role for assessing functional capacity preoperatively, even if its performance for cardiovascular risk stratification is inferior to biomarkers or clinical risk prediction tools.
No cardiac testing is routinely indicated for low-risk, asymptomatic individuals.
Cardiac testing should be considered for those who have cardiac symptoms, have a cardiac history, or have elevated cardiac risk, such as those who are undergoing elevated risk procedure or have multiple c
American guidelines recommend a preoperative resting 12-lead ECG for patients with a known cardiac history,except those undergoing a low-risk procedure.
It can also provide some prognostic information regarding underlying cardiovascular disease:arrhythmia, left ventricular (LV) hypertrophy, and bundle branch blocks and therefore can be considered in patients without a known cardiac history.
Echocardiography can be used to assess LV function or in conjunction with stress testing.
Guidelines find that assessment of LV function is reasonable in those who have unexplained dyspnea, a history of CHF who have had a change in clinical status or have not had assessment in the past year, in those who are undergoing high risk surgery, in those who have valvular heart, and potentially in those who have a history of PH.
Stress testing options, including exercise stress testing (EST), CPET, and pharmacologic stress testing.
Stress testing is not indicated in patients who have excellent exercise capacity (>10 METs).
Guidelines recommend considering preoperative stress testing only in patients who have unknown or poor functional capacity (<4 METs).
CPET provides an objective measure of the integrated function of the cardiac, circulatory, respiratory, and muscular systems under physiologic stress.
CPET measures the anaerobic threshold and peak oxygen uptake, which are thought to aid more definitively in risk assessment.
A study evaluating CPET, found no clear association with cardiac risk, although it did predict overall risk for postoperative complications.
The current guidelines would not support CPET as a cardiac-specific risk assessment tool, but there might be a role in predicting noncardiac complications.
For patients who are unable to exercise, pharmacologic stress testing can be used.
Vasodilators, such as adenosine and dipyridamole, can induce bronchospasm, precipitate hypotension, accentuate sinus node dysfunction and high-degree atrioventricular block, and increase the risk for an ischemic event during testing.
Inotropic drugs, such as dobutamine, can result in severe systemic hypertension, ventricular arrhythmias, and rapid ventricular response in atrial fibrillation.
Inotropic drugs are contraindicated in the setting of a recent MI, unstable angina, aortic dissection, and hemodynamically significant left ventricular outflow tract obstruction.
The dobutamine stress echocardiogram is the only common pharmacologic test that provides an ischemic threshold.
Nuclear stress tests include single photon emission computed tomography (SPECT) and positron emission tomography (PET).
The most common agents used in SPECT imaging are based on technetium-99m.
The most common agents used in PET imaging are rubidium-82 and N13-ammonia.
SPECT and PET stress testing provide information on cardiac size and function, myocardial perfusion, and viability.
They tests are preferred in the setting of left bundle branch block, as echocardiography has a significant false-positive rate from ventricular dyssynchrony and in patients with obesity or severe lung disease.
Indications for preoperative conventional angiography are identical to those in the nonoperative setting; they would include symptoms consistent with acute coronary syndrome and unstable angina.
Although coronary computed tomographic angiography is less invasive than angiography, it was found to overestimate risk in the Vascular Events in Noncardiac Surgery Patients,and it is not recommended for perioperative risk stratification.
American guidelines recommend preoperative NT-proBNP for diagnosing or optimizing heart failure.
European guidelines state that BNP and NT-proBNP measurements can be considered to obtain additional independent prognostic information in high-risk patients undergoing surgery.
Some guidelines strongly recommend measuring BNP or NT-proBNP before noncardiac surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have an RCRI score of 1 or greater.
A systematic review and meta-analysis published showed that a postoperative measurement of BNP or NT-proBNP further enhanced risk stratification above just a preoperative measurement, and it was the strongest predictor of mortality and nonfatal MI postoperatively compared with the preoperative value.
American guidelines suggest obtaining troponin levels postoperatively for signs or symptoms of MI and do not recommend routinely checking troponins.
European guidelines recommend obtaining troponins in high-risk patients both before surgery and for 48 to 72 hours after major surgery..
Canadian guidelines use a decision tree that recommends daily postoperative troponins for 2 to 3 days in patients older than 65 years or 18 to 64 years old with significant cardiovascular disease or a positive preoperative BNP or NT-proBNP.
Patients with severe or symptomatic cardiac disease represent an elevated-risk population that require careful consideration before proceeding with surgery.
Elective surgeries can be delayed for cardiac evaluation or intervention, whereas emergent surgery should not be delayed.
Management of time-sensitive and urgent surgery should be individualized.
Any form of symptomatic obstructive coronary disease requires additional evaluation prior surgery.
Acute coronary syndrome (defined as ST-segment elevation MI, non–ST-segment elevation MI, and unstable angina) significantly increases perioperative risk of MACE.
There is almost threefold increase in relative risk for patients who had an MI in the last 180 days.
If patients have signs or symptoms of acute coronary syndrome, surgery should be delayed unless the surgical need is emergent and the risk of delaying surgery outweighs the benefit of revascularization.
If acute coronary syndrome is identified, it should be managed as per published practice guidelines.
Postoperative MI and mortality continued to decrease as surgery was delayed up to approximately 60 days after the initial event, allowing healing of the myocardial tissue and stabilization of the inflammatory and coagulation responses in the body.
American guidelines recommend that elective surgery should be delayed at least 60 days after MI even in the absence of coronary intervention.
Guidelines recommend dual antiplatelet therapy (DAPT) for a minimum of 1 month after bare metal stent, a minimum of 3-6 months after drug-eluting stent (with 6 months being preferred), and a minimum of 12 months after an acute coronary syndrome.
European guidelines recommend DAPT for a minimum of 1 month regardless of stent type, up to 6 months depending on risk factors (eg, acute coronary syndrome at stent implantation, complex coronary anatomy, chronic kidney disease, diabetes, prior stent thrombosis while receiving antiplatelet therapy).
Perioperative guidelines incorporate elements of contemporary tools for perioperative cardiovascular risk stratification, include current definitions of operative urgency and risk, and provide evidence-based consensus on perioperative cardiovascular care.
Preoperative cardiac stress testing should be reserved for patients who have elevated risk and poor functional capacity, and they should be considered only when the results would change perioperative management.
Postoperative surveillance for MACE is not routinely recommended in the guidelines; however, the European guideline endorses postoperative measurement of troponins and ECGs in patients who are believed to be at high risk (>5%) of MACE.
The American guidelines recommend ECG and troponins in patients who have symptoms of MI postoperatively, but do not make clear recommendations as to when or if high-risk patients should have surveillance for ischemia in the absence of symptoms.
The role of preoperative biomarkers: but they do appear to contribute to preoperative cardiac risk assessment.
The utility of functional capacity in predicting MACE is still unclear. It is also not clear whether improving functional capacity preoperatively decreases MACE postoperatively.