The American Journal of Circulation (October 2007) published the Guidelines for Perioperative Cardiovascular Evaluation and Treatment of Noncardiac Surgery developed by the American College of Cardiology (ACC) and the American Heart Association (AHA). This guideline is based on the new literature in the past 5 years, and the 2002 version of the guideline has been revised to provide some new ideas and increase the length of perioperative treatment compared with the previous guideline, which is a good guidance for cardiovascular surgeons in China. This article provides a brief overview of its main contents.
I. Purpose of the guidelines
The purpose of the preoperative evaluation is not to give medical approval, but to assess the patient’s current medical status. If the patient has sufficient cardiovascular information, is symptomatically stable, and further evaluation does not interfere with perioperative management, a consultation may be unnecessary. The purpose of the consultation is to give the patient the most appropriate treatment. Preoperative interventions do not reduce the risk of noncardiac surgery unless the patient is at the point where intervention is necessary.
II. Epidemiology
The prevalence of cardiovascular disease increases with age, and it is estimated that the number of people over 65 years of age in the United States will increase by 25% to 35% over the next 30 years, and accordingly this age group is the population with the largest number of surgical procedures. Thus, among older individuals, noncardiac surgery will increase from the current 6 million to 12 million per year, with nearly a quarter of these patients (primarily those requiring abdominal, thoracic, vascular, and orthopedic surgery) being significantly associated with perioperative cardiovascular disability and death.
III. General patient assessment
Patients requiring evaluation and treatment prior to noncardiac surgery are limited to those with active cardiac disease, such as severe or unstable angina, recent heart attack, advanced heart failure, severe arrhythmias, and severe heart valve disease.
Patients classified as high risk due to age or known coronary artery disease who are asymptomatic and also able to exercise for 30 minutes per day do not require further evaluation. In contrast, a more comprehensive evaluation, including history and physical examination, should be performed in a sedentary patient with no history of cardiovascular disease but with clinical risk factors suggestive of increased perioperative risk.
In patients with acute heart failure, chest radiographic evidence of pulmonary congestion and pulmonary rales correlate well with elevated pulmonary venous pressure. However, in patients with chronic heart failure, there may not be any of these signs of pulmonary congestion. A positive jugular venous filling or hepatic jugular reflux sign is a more reliable indication of volume overload. In the absence of these signs, peripheral edema is not a reliable indicator of chronic heart failure.
The assessment of the cardiovascular system must take into account the patient’s systemic health status, and a number of associated conditions often exacerbate the risk of anesthesia and complicate the management of cardiac problems. Common medical-related conditions include pulmonary disorders, diabetes mellitus, renal impairment, and anemia.
For acute surgical procedures, preoperative evaluation should be limited to tests necessary for simple and emergency procedures, such as rapid determination of cardiovascular vital signs, volume status, red blood cell pressure, electrolytes, renal function, urinalysis and electrocardiogram, etc. More comprehensive evaluation can be performed after the surgical procedure.
IV. Step-by-step perioperative cardiac assessment method
Step 1 Determine the urgency of non-cardiac surgery. If the procedure is urgent, admit to the operating room immediately for perioperative monitoring and postoperative risk stratification and address risk factors (Class I Recommendation Level C Evidence,IC). Postoperative risk stratification for elective surgery is often performed after the patient has recovered to avoid blood loss, organismal derangement, and other postoperative complications that may confound the results of noninvasive investigations. If it is a non-urgent procedure proceed to the next step.
Step 2 The patient has no active heart disease, if not, proceed to the next step. If there is unstable angina, decompensated heart failure, severe arrhythmias, or valve disease often leads to postponement or cancellation of
surgery until the heart disease is diagnosed and appropriately treated. (IB) Many patients with these conditions require coronary angiography to evaluate further treatment options. Maximum drug therapy for patients scheduled for surgery is
appropriate.
Is the patient having a low-risk procedure? If it is a low-risk procedure, go to the next step. Even in high-risk patients, the rates of disability and death associated with low-risk noncardiac surgery
are less than 1% in total. The types of low-risk procedures include endoscopic treatments, skin treatments, cataract surgery, breast surgery, and procedures that do not require bed rest. (IB) Some studies have reported that most same-day mortality rates for non-emergency cardiac surgery are actually lower than 30-day postoperative mortality rates, suggesting that the increased risk of performing non-emergency cardiac surgery can be ignored or protected.
Step 4 Is the patient in good functional status? Are there any symptoms? Functional status can be determined by metabolic equivalents (METs). For example, a 40-year-old male weighing 70 kg at rest has a basal oxygen consumption of 3.5 ml/kg.min, which is 1 MET. Functional status is classified as excellent (>10 METs), good (7-10 METs), moderate (4-7 METs), and poor (<4 METs). If the patient has MET ≥4 and is asymptomatic, surgery can be performed as planned (IB). Patients who are unable to achieve 4 METs in most normal daily life have an increased perioperative cardiac and long-term risk and proceed to the next step if the status is poorly functional or unclear.
Step 5 If the patient’s functional status is poor, symptomatic or unclear, the decision to require further evaluation may be based on the presence or absence of clinical risk factors. Without clinical risk factors, the procedure can be performed as planned (IB). If the patient has one to two clinical risk factors or more than three clinical risk factors requiring moderate risk surgery (perioperative mortality 1% to 5%), it is reasonable to operate as planned after controlling the heart rate with β-blockers (IIaB), or consider non-invasive examination (IIbB)
V. Evaluation of specific diseases
(i) Coronary artery disease Many patients without cardiac symptoms may have severe double or triple vascular disease because these patients present atypically or have limited activity function due to severe arthritis or peripheral vascular disease, which is not easily diagnosed. In patients with established coronary artery disease and previous occult coronary artery disease, the important purpose of the preoperative history and physical examination for noncardiac surgery is to identify: 1. the amount of myocardium at risk; 2. the threshold size of myocardial ischemia, i.e., the amount of exercise load at which ischemia occurs; 3. how well the patient’s ventricles are functioning; and 4. whether the patient is receiving optimal pharmacologic therapy, given the limited value of current evidence regarding coronary revascularization prior to noncardiac surgery. value is limited, preoperative testing is limited to the benefits of coronary revascularization independent of patients undergoing noncardiac surgery.
(ii) Hypertension Many studies have found that grade 1 or 2 hypertension is not an independent risk factor for perioperative cardiovascular complications and that antihypertensive therapy is beneficial in reducing mortality from coronary artery disease and stroke, but few patients are treated with antihypertensive therapy and even fewer have effective blood pressure control. Therefore, perioperative
The perioperative evaluation is therefore an excellent opportunity to identify and treat patients with hypertension. Hypertension is associated with underlying coronary artery disease, and preoperative blood pressure control can help reduce the tendency for perioperative myocardial ischemia, which is associated with postoperative cardiac mortality. In patients with confirmed hypertension, antihypertensive medications should be continued in the perioperative period. β-blockers are particularly suitable for the treatment of preoperative hypertension. Preoperative β-blockers reduce the incidence of postoperative atrial
incidence of postoperative atrial fibrillation and can reduce the morbidity and mortality of cardiovascular complications of noncardiac surgery. Special care should be taken when withdrawing β-blockers and colistin to avoid rebound of heart rate and blood pressure. For patients who are unable to take oral medications
hypertensive patients, parenteral β-blockers and colistin transdermal patches can be given.
In grade 3 hypertension, the potential benefit of optimizing the effect of antihypertensive medications and delaying surgery should be weighed against the risk of delaying surgery. Rapid intravenous administration can often control blood pressure within a few hours, but
Randomized trials demonstrating the benefits of delaying surgery are lacking. Preoperative hypertensive patients have been reported to be more likely to have intraoperative hypotension than nonhypertensive patients, and intraoperative hypotension has a higher incidence of perioperative cardiac and renal complications than intraoperative hypertension. The greater risk of hypotension, especially in patients on ACEI or ARB, may be related to decreased blood volume, and some authors suggest that ACEI and ARB should be discontinued on the morning of surgery.
(iii) Heart failure Several studies have clearly established that heart failure at the time of noncardiac surgery is associated with poor prognosis. Efforts should be made to detect unsuspected heart failure through careful history taking and physical examination. If possible, it is important to identify the cause of heart failure, as this may provide clues about the risk of perioperative heart failure and death. For example heart failure caused by hypertensive heart disease versus heart failure caused by coronary artery disease, both of which predict different risks.
(iv) Cardiomyopathy Little information is available on the preoperative evaluation of patients with cardiomyopathy for noncardiac surgery. Current preoperative recommendations are based on a thorough understanding of the pathophysiology of the development of cardiomyopathy, and every reasonable effort should be made to define the cause of cardiomyopathy prior to surgery; knowledge of the cause will aid in the management of intraoperative and postoperative intravenous fluids. In patients with a history or signs of heart failure, preoperative application of 2D ultrasound is recommended for assessment of left ventricular systolic and diastolic function.
(v) Valvular heart disease Cardiac murmurs are common in patients preparing for noncardiac surgery, and the consultant must distinguish between functional or organic murmurs. Identify the source of the murmur to determine which patients need prevention of endocarditis and which patients need further quantification of the severity of valvular disease. It is recommended that the internist review all data and use his or her personal clinical experience to determine whether prophylactic measures need to be recommended.
Severe aortic stenosis is extremely dangerous for noncardiac surgery and has a surgical mortality rate of approximately 10%. If symptomatic, elective noncardiac surgery should usually be cancelled or postponed, and for elective noncardiac surgery, patients should undergo aortic valve replacement before elective surgery. If aortic stenosis is severe but asymptomatic, surgery should be cancelled or deferred if valve evaluation has not been performed within the last 1 year. If the patient is not a candidate for valve replacement, percutaneous puncture balloon aortic valve dilatation can be used as a transitional approach in adult patients who are hemodynamically unstable, whose valve replacement procedure is risky, or who are contraindicated because of severe medical disease.
In mild or moderate mitral stenosis, control of the perioperative heart rate should be ensured because the reduction in end-diastolic filling of the left ventricle with tachycardia can lead to pulmonary congestion. However, surgical correction of mitral stenosis before noncardiac surgery is not indicated.
mitral stenosis is not indicated. Unless the valve needs to be improved to prolong survival and prevent complications. When mitral stenosis is severe, patients may benefit from mitral balloon dilatation or open-heart surgical repair prior to high-risk surgery.
Recommendations for aortic regurgitation should address volume control and afterload reduction. In contrast to mitral stenosis, severe aortic regurgitation does not benefit from slowing the heart rate because the prolonged diastolic phase increases regurgitant flow.
(vi) Arrhythmias and conduction disturbances Supraventricular and ventricular arrhythmias have been shown to be independent risk factors for perioperative coronary events. More recent studies with ambulatory ECG monitoring have found that asymptomatic ventricular arrhythmias, including paired ventricular premature and nonsustained ventricular tachycardia, do not increase cardiac complications after noncardiac surgery. Nonetheless, the cause of the arrhythmia, such as underlying cardiopulmonary disease, myocardial ischemia or infarction, or myocardial infarction, should be clarified.
Myocardial ischemia or infarction, drug toxicity, or metabolic disturbances.
Certain arrhythmias, although relatively benign, may mask underlying cardiac problems, such as atrial fibrillation and supraventricular arrhythmias that can cause increased myocardial oxygen demand in patients with coronary artery disease, leading to myocardial ischemia. Associated with
Atrial fibrillation with bypass has a rapid rhythm that may deteriorate into ventricular fibrillation. Ventricular arrhythmias, whether single ventricular premature, complex ectopic ventricular premature, or nonsustained ventricular tachycardia, usually do not require treatment unless they compromise the patient’s hemodynamics. Although frequent ventricular premature and nonsustained ventricular tachycardia are considered risk factors for the development of arrhythmias and ventricular arrhythmias during intraoperative and long-term postoperative follow-up, they do not increase the risk of perioperative nonfatal infarction or cardiac death. Patients who develop persistent and/or nonsustained ventricular tachycardia in the perioperative period should be referred to a cardiologist for further evaluation, including ventricular function, and coronary screening.
Complete AV block, if not found to increase the risk of surgery, must be paced with permanent or temporary transvenous pacing. In contrast, ventricular conduction delay, even in the presence of left or right bundle branch block, rarely progresses to complete heart block in the perioperative period if there is no history or symptoms of severe heart block.
The evaluation of the patient with a pacemaker includes: 1. identification of the type of pacemaker; 2. whether the patient is pacemaker-dependent for bradycardia; and 3. identification of the pacemaker’s programmed adjustment and battery status. If there is pacemaker dependence, the pacemaker should be pre-programmed to asynchronous mode (VOO or DOO) or a magnet should be placed on the pacemaker at the time of surgery. Buried or cardioverter-defibrillators (ICDs) should be turned off in programmed mode for tachyarrhythmia therapy before surgery and restored after surgery to avoid intraoperative misdischarge.
VI. Perioperative treatment
(i) Coronary revascularization (CABG or PCI) before non-cardiac surgery is beneficial (Class I recommendation Level A evidence), as follows
1. Patients with stable angina pectoris with severe left main stenosis.
2. Patients with stable angina with a three-vessel lesion, with a greater benefit in those with LVEF <0.50.
3. Patients with stable angina with two-vessel disease (severe proximal left anterior descending stenosis, LVEF < 0.50, or non-invasive test evidence of myocardial ischemia).
4. High-risk unstable angina or non-ST-segment elevation infarction.
5. Acute ST-elevation infarction.
Except for the above patients, PCI performed prior to non-cardiac surgery is not valuable in preventing peri-procedural cardiac events.
(b) The 2007 AHA/ACC/SCAI/ACS/ADA Scientific Committee jointly concluded that premature discontinuation of dual antiplatelet therapy significantly increases the risk of potentially fatal intra-branch
(c) The 2007 AHA/ACC/SCAI/ACS/ADA Scientific Committee agreed that premature discontinuation of dual antiplatelet therapy significantly increases the risk of in-stent thrombosis that may lead to death. Therefore, the need for dual antiplatelet therapy should be discussed prior to stent implantation. Patients who are unable to tolerate 12 months of thienopyridine (clopidogrel or Raltegravir) therapy, whether for financial or other reasons, should avoid the use of drug lavage.
Drug-eluting stents (DES) should be avoided if the patient cannot tolerate 12 months of thienopyridine (clopidogrel or reserpine) therapy, whether for financial or other reasons. If a patient is likely to undergo surgery within 12 months of PCI, consideration should be given to implanting a bare metal stent (BMS) or to balloon dilation only, rather than routine DES implantation.
Although the risk of restenosis is higher with BMS implantation than with DES, restenotic lesions are usually not fatal. Even if it occurs, it may present as an acute coronary syndrome, and PCI can often be repeated if necessary.
If necessary, PCI can often be repeated. Patients with DES should be given appropriate and adequate pre-discharge instructions and dual antiplatelet therapy should not be discontinued prematurely. If a patient is discontinued from thienopyridine therapy for surgery, aspirin should be continued if possible.
Aspirin should be continued if possible, and dual antiplatelet therapy should be resumed as soon as possible after surgery to prevent late thrombosis.
The absolute risk of increased bleeding with aspirin combined with clopidogrel dual antiplatelet therapy compared with aspirin alone is 0.4% to 1.0%. Some procedures, such as dental surgery, have a low risk of bleeding and do not require discontinuation of dual antiplatelet therapy. Selective non-cardiac procedures, such as aspirin alone or clopidogrel alone, do not require discontinuation.
(iii) Perioperative beta-blocker therapy, Class I recommendations are: 1. Patients who are receiving beta-blockers for angina pectoris, symptomatic arrhythmias, hypertension, or other ACC/AHA guideline Class I recommended indications should continue beta-blockers if they undergo surgery (Class C evidence). 2. High-risk cardiac risk patients with evidence of ischemia on preoperative testing who undergo vascular surgery beta-blockers should be given (level B evidence).
Although several meta-analyses have been performed, some with conflicting findings, there are still only a very small number of randomized trials on the effectiveness of β-blockers. Few studies have compared different beta-blockers, but identifying the appropriate target population, preoperative titration time, and route of administration are insufficient. There is growing evidence that with beta-blockers, the effective target value for heart rate control should be at least <65 bpm.
(iv) Perioperative statin therapy
The guidelines consider that patients currently taking statins and planning non-cardiac surgery should continue to use statins (IB). The use of statins is reasonable in patients with or without clinical risk factors who are planning to undergo vascular surgery (IIaB). Statin use may be considered in patients with at least 1 clinical risk factor who will undergo moderate risk surgery (IIaC).
The evidence obtained to date suggests a protective effect of perioperative statin application for cardiac complications in noncardiac surgery, but most of the data are observational, the timing and duration of patient initiation of statin is unclear, and the dose of statin, target values (reduction of LDL-C levels), and indications for statin therapy are mostly unclear, and sufficiently convincing randomized trials are needed to clarify the treatment of perioperative statins .