Incidence

Increasing as healthcare availability, imaging techniques, and average life expectancy increase.

Prevalence

1–1.5% of the total US population has ischemic heart disease.

• Ischemic cardiomyopathy (ICM) is the most common consequence of CAD.
• The TIMI (Thrombolysis in Myocardial Infarction) risk score looks at 7 factors to determine risk.
  • Age 65 years or older
  • At least 3 risk factors for coronary artery disease
  • Prior coronary stenosis of 50% or more
  • ST-segment deviation on electrocardiogram at presentation greater than 0.5 mm
  • At least 2 anginal events in prior 24 hours
  • Use of aspirin in prior 7 days
  • Elevated serum cardiac markers

As determined by number of risk factors, risk of all-cause mortality, new or recurrent MI, or severe recurrent ischemia requiring urgent revascularization within the first 2 weeks are: 1 = 5%, 2 = 8%, 3 = 13%, 4 = 20%, 5 = 26%, 6/7 = 41%

Ischemic heart disease is the leading cause of death in the US.

History

Family history, previous diagnosis of CAD, risk factors

Signs/Physical Exam

Congestive heart failure

Labs/Studies

• Preoperative labs are based on type of surgery, medications, severity of CAD.
• Diagnosis of CAD requires imaging: coronary angiogram, radionucleotide perfusion scans, magnetic resonance imaging.
• Computed tomography (4).

• Midazolam to prevent anxiety and increased sympathetic tone, as needed
• Narcotics for sympathetic stability and pain control, as needed
• Patients on beta blockers should have their doses continued in the perioperative period.

• Risk for intraoperative MI and SCD
• Risk for transfusion
• Invasive monitoring

• Depends on surgical procedure and patient preference
• If possible, MAC is preferred (less expected hemodynamic perturbations)
• If a neuraxial technique is chosen, aspirin does not contraindicate placement

• Standard ASA monitors
• 5-lead EKG has increased sensitivity for LV ischemia.
• Arterial line allows beat-to-beat BP monitoring or minimally invasive CO monitoring.
• Central venous line may be considered to guide fluid administration and for fluid and/or vasopressor delivery.
• Pulmonary artery catheter may be considered if the patient is at high risk for decompensation to monitor right and LV function, volume status, cardiac output, and mixed venous saturation
• Transesophageal echocardiography may be considered for hypertrophic cardiomyopathy and management of perioperative events.
• Newer noninvasive CO monitors – NICOMs based on bioimpedance or bioreactance.

• Smooth, controlled induction to maintain vital signs and coronary perfusion within normal limits.
• Narcotic-based inductions may have a more gradual and minimal impact on BP and cardiac function, and may be preferable to the potentially harsher sedative-hypnotic only inductions.
• Short-acting medications should be available to treat increases in heart rate (esmolol), HTN (esmolol, nitroglycerin, calcium channel blockers, propofol), and hypotension (phenylephrine, ephedrine).

• Volatile and/or IV anesthetics may be used; neither technique has shown superiority in patients with coronary artery disease.
• Maintaining myocardial oxygen supply and decreasing demand are more important than the specific anesthetic technique.
  • Decrease the heart rate, while maintaining an adequate cardiac output.
  • Monitor and maintain normal sinus rhythm
  • Decrease contractility while maintaining adequate cardiac output; avoid and anticipate sympathetic stimulation (e.g., incision, retraction, pain, adequate depth of anesthesia) with narcotics and/or deepening the anesthetic
  • Optimize the afterload; an adequate diastolic perfusion pressure is necessary to maintain cardiac perfusion (CPP = DBP–LVEDP). However, increases in afterload require an increase in myocardial oxygen consumption
  • Optimize preload; an adequate intravascular fluid volume is necessary to maintain an adequate stroke volume (Starling curve).
  • Maintain the oxygen content of arterial blood with an adequate hematocrit, oxygen saturation, and ventilator settings.
  • Alternatively, support life in severe systolic dysfunction with inotropes and vasopressors as needed.
• Normothermia. Measures to avoid hypothermia should be made; shivering can increase myocardial oxygen consumption significantly
• Intraoperative ischemia should be monitored and treated utilizing the coordinated efforts of the healthcare team, so as to optimize myocardial oxygen supply and demand.

Have narcotics, anxiolytics, antihypertensives, and beta-blockers available to maintain postoperative vital sign stability