Should all patients have a resting 12-lead ECG before elective noncardiac surgery?
A 55-year-old lawyer with hypertension well controlled on lisinopril and amlodipine is scheduled for elective hernia repair under general anesthesia. His surgeon has referred him for a preoperative evaluation. He has never smoked, runs 4 miles on days off from work, and enjoys long hiking trips. On examination, his body mass index is 26 kg/m2 and his blood pressure is 130/78 mm Hg; his cardiac examination and the rest of the clinical examination are unremarkable. He asks if he should have an electrocardiogram (ECG) as a part of his workup.
A preoperative ECG is not routinely recommended in all asymptomatic patients undergoing noncardiac surgery.
Consider obtaining an ECG in patients planning to undergo a high-risk surgical procedure, especially if they have one or more clinical risk factors for coronary artery disease, and in patients undergoing elevated-cardiac-risk surgery who are known to have coronary artery disease, chronic heart failure, peripheral arterial disease, or cerebrovascular disease. However, a preoperative ECG is not routinely recommended for patients perceived to be at low cardiac risk who are planning to undergo low-risk surgery. In those patients it could delay surgery unnecessarily, cause further unnecessary testing, drive up costs, and increase patient anxiety.
Here we discuss the perioperative cardiac risk based on type of surgery and patient characteristics and summarize the current guidelines and recommendations on obtaining a preoperative 12-lead ECG in patients undergoing noncardiac surgery.
RISK DEPENDS ON TYPE OF SURGERY AND PATIENT FACTORS
Physicians, including primary care physicians, hospitalists, cardiologists, and anesthesiologists, are routinely asked to evaluate patients before surgical procedures. The purpose of the preoperative evaluation is to optimize existing medical conditions, to identify undiagnosed conditions that can increase risk of perioperative morbidity and death, and to suggest strategies to mitigate risk.1,2
Cardiac risk is multifactorial, and risk factors for postoperative adverse cardiac events include the type of surgery and patient factors.1,3
Cardiac risk based on type of surgery
Low-risk procedures are those in which the risk of a perioperative major adverse cardiac event is less than 1%.1,4 Examples:
- Ambulatory surgery
- Breast or plastic surgery
- Cataract surgery
- Endoscopic procedures.
Elevated-risk procedures are those in which the risk is 1% or higher. Examples:
- Intraperitoneal surgery
- Intrathoracic surgery
- Carotid endarterectomy
- Head and neck surgery
- Orthopedic surgery
- Prostate surgery
- Aortic surgery
- Major vascular surgery
- Peripheral arterial surgery.
Cardiac risk based on patient factors
The 2014 American College of Cardiology and American Heart Association (ACC/AHA) perioperative guidelines list a number of clinical risk factors for perioperative cardiac morbidity and death.1 These include coronary artery disease, chronic heart failure, clinically suspected moderate or greater degrees of valvular heart disease, arrhythmias, conduction disorders, pulmonary vascular disease, and adult congenital heart disease.
Patients with these conditions and patients with unstable coronary syndromes warrant preoperative ECGs and sometimes even urgent interventions before any nonemergency surgery, provided such interventions would affect decision-making and perioperative care.1
The risk of perioperative cardiac morbidity and death can be calculated using either the Revised Cardiac Risk Index scoring system or the American College of Surgeons National Surgical Quality Improvement Program calculator.157 The former is fairly simple, validated, and accepted, while the latter requires use of online calculators (eg, www.surgicalriskcalculator.com/miorcardiacarrest, www.riskcalculator.facs.org).
The Revised Cardiac Risk Index has six clinical predictors of major perioperative cardiac events:
- History of cerebrovascular disease
- Prior or current compensated congestive heart failure
- History of coronary artery disease
- Insulin-dependent diabetes mellitus
- Renal insufficiency, defined as a serum creatinine level of 2 mg/dL or higher
- Patient undergoing suprainguinal vascular, intraperitoneal, or intrathoracic surgery.
A patient who has 0 or 1 of these predictors would have a low risk of a major adverse cardiac event, whereas a patient with 2 or more would have elevated risk. These risk factors must be taken into consideration to determine the need, if any, for a preoperative ECG.
