What is the appropriate initial test for evaluating left ventricular (LV) function in patients at intermediate risk undergoing preoperative assessment?

Appropriate Testing of Left Ventricular Function for Preoperative Risk Assessment in Intermediate Risk Patients

For patients at intermediate risk undergoing preoperative assessment, transthoracic echocardiography (TTE) is the appropriate initial test for evaluating left ventricular function, but should only be performed in patients with dyspnea of unknown origin, heart failure with worsening symptoms, or suspected new/worsening ventricular dysfunction - routine evaluation in asymptomatic patients is not recommended. 1

Indications for LV Function Assessment

Recommended (Class I)

• Patients with new dyspnea of unknown origin 1
• Patients with physical examination findings of heart failure 1
• Patients with suspected new or worsening ventricular dysfunction 1

Reasonable (Class IIa)

• Patients with known heart failure with worsening dyspnea or other change in clinical status within the past 12 months 1
• Patients undergoing high-risk surgery (particularly vascular procedures) 1

Not Recommended (Class III)

• Routine preoperative evaluation of LV function in asymptomatic and clinically stable patients 1
• Patients undergoing low-risk procedures (e.g., cataract surgery) regardless of cardiac risk factors 2

Evidence Supporting These Recommendations

The 2024 AHA/ACC guidelines (the most recent and authoritative source) clearly state that routine preoperative evaluation of LV function is not recommended in asymptomatic and clinically stable patients due to lack of benefit (Class III recommendation with Level B-NR evidence) 1. This recommendation is consistent across multiple guidelines spanning from 2007 to 2024 1.

The evidence shows that while abnormal LV function is associated with increased perioperative major adverse cardiac events (MACE), preoperative assessment of LV function in stable patients has not been shown to improve outcomes 1. In a meta-analysis, LV ejection fraction <35% had a sensitivity of only 50% and specificity of 91% for predicting perioperative cardiac events 1.

Clinical Decision Algorithm for LV Function Assessment

1. First, assess for specific clinical indications:

   • New or worsening dyspnea
   • Physical examination findings of heart failure
   • Suspected new/worsening ventricular dysfunction
   • Known heart failure with change in clinical status

2. If any of these indications are present:

   • Proceed with transthoracic echocardiography (TTE)

3. If none of these indications are present:

   • Routine LV function assessment is not recommended
   • Focus on other aspects of preoperative risk assessment

Important Considerations and Pitfalls

• Poor predictive value: The finding of LV dysfunction has poor sensitivity (43%) and positive predictive value (13%) for predicting perioperative events 1

• Surgical risk matters: For high-risk procedures (particularly vascular surgery), echocardiographic assessment may provide incremental value in risk stratification 1, 3

• Avoid unnecessary testing: Routine testing in asymptomatic patients can lead to unnecessary downstream testing, increased costs, and potential delays in surgery without improving outcomes 1

• Point-of-care options: In specific situations, point-of-care assessment using focused cardiac ultrasound (FoCUS) may be considered when performed by trained individuals, though comprehensive TTE remains the standard of care 1

• Diastolic dysfunction: Grade 3 diastolic dysfunction has been associated with higher perioperative risk and may warrant consideration in the preoperative assessment 1

By following these evidence-based recommendations, clinicians can appropriately select patients who will benefit from preoperative LV function assessment while avoiding unnecessary testing in those unlikely to benefit.