Preoperative Cardiac Evaluation in Non-cardiac Surgery : Mnemonic

Besides, for the emergency/urgent surgeries, one needs to evaluate 4 variables in the preoperative cardiac evaluation of the patient for the non-cardiac surgery. We have elaborated the mnemonics used by CasesBlog. These variables can be remembered by the mnemonic PAST.

1. Patient risk
2. Activity level (METs)
3. Surgical risk
4. Test (Stress test) or Treat (Beta blockers)

1. Patient risk for Major Adverse Cardiac Events (MACE):

MACE can be calculated by variety of methods but the most commonly used is the Revised Cardiac Risk Index (RCRI). RCRI comprises of 6 variables each scored 1 which can be remembered using the mnemonic 4CHD.

• CAD (Coronary artery disease)
• CHF (Congestive heart failure)
• CVA (Cerebrovascular disease)
• CKD (Creatinine >2 mg/dl)
• High risk surgery (Discussed in point number 3)
• DM requiring insulin

RCRI score predicts risk of MACE as follows:

• 0 – 0.4%
• 1 – 1%
• 2 – 2.4%
• 3 or more – 5.4%

With MACE <1% (considered low risk), one can proceed to surgery. If MACE is 1% or more, i.e. more than 1 clinical risk factors (elevated risk), one needs to determine functional capacity with Metabolic Equivalent Tasks (METs).

2. Activity level (METs):

The determining level for surgery or testing is the 4 METs. If a patient can walk 4 mph or faster on level ground, climb a flight of stairs, walk up a hill, run a short distance, do heavy work around house, involve in recreational sports activities, the functional capacity of patient is 4 or more METs.

• 4 or more METs: Proceed to surgery
• <4 METs: Test (Stress test)

3. Surgical risk:

a. High risk (>5% risk of cardiac death or nonfatal MI): Aortic or major vascular surgery, Intraperitoneal surgery, Intrathoracic surgery

b. Intermediate risk (1-5% risk of cardiac death or nonfatal MI): Carotid endarterectomy, Head/neck surgery, Orthopedic surgery, Prostate surgery

c. Low risk (<1% risk of cardiac death or nonfatal MI): Ambulatory surgery, Endoscopic procedures, Superficial procedure, Cataract surgery, Breast surgery

4. Test (Stress test) or Treat (Beta blockers):

If RCRI >1% with <4 METs, pharmacological stress testing (using dobutamine, adenosine, etc.) is recommended.

Revascularization before noncardiac surgery is recommended in cases where revascularization would otherwise be indicated according to existing clinical practice guidelines; not recommended exclusively to reduce perioperative cardiac events.

Beta blockers should be continued in patients using them chronically. If there is ischemia on stress test of if ≥3 or more RCRI risk factors are present, it may be reasonable to begin perioperative beta blockers. When starting beta blockers before surgery, do so ≥1 day before (recommended ≥1 wk to 2 wks before; do not start on day of surgery – harmful in POISE study). More cardioselective beta blockers may be better.

Reference: 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery

2016 Canadian Cardiac Society (CCS) guideline emphasizes the use of biomarkers.

Send NT-proBNP or BNP if any 1 of CAR:

1. Cardiovascular disease in 45-64 years aged
2. Age 65 years or more
3. RCRI 1 or more

Risk of death or MI based on NT-prBNP and BNP:

1. NT-proBNP <300 ng/L or BNP <92 mg/L: ~5%
   • No additional routine postoperative monitoring required
2. NT-proBNP 300 ng/L or more or BNP 92 mg/L or more: ~22%
   • Postoperative monitoring: Measure troponin daily X 48-72 hours, Obtain ECG in PACU

Reference: 2016 CCS guideline on perioperative cardiac risk assessment and management of patients undergoing noncardiac surgery