This was a first for me as a surgeon. I’ve never had a patient code in the OR, and looking back on the number of high risk patients I’ve taken care of, I’m surprised it’s never occurred before. Something important for all of us podiatrists to know is that we are ultimately responsible for our patients, being the “captain of the ship ” so to speak – even though we are the foot surgeon and not the medical doctor. So, to help all of us prevent what happened to my patient, I’m going to quickly review a lecture provided by a cardiologist colleague of mine, whose content was based on the most recent recommendations of the American College of Cardiology/American Heart Association (ACC/AHA) guidelines on cardiac patients undergoing noncardiac surgery¹. Obviously, I’m not a cardiology expert, so I urge everyone to research this topic further for yourselves.

First, we have to define urgency and risk of cardiac events during noncardiac surgery. The ACC/AHA defines the following surgical categories:

• Emergent – threat to life or limb; minimal preoperative evaluation possible (< 6 hours)
   
• Urgent – threat to life or limb; some time for limited preoperative evaluation (6-24 hours)
   
• Time-sensitive – a delay of 1-6 weeks is possible for evaluation and changes in management.
   
• Elective – a procedure that may be delayed for > 1 year.

The ACC/AHA truncated prior risk categorization of major adverse cardiac events (MACE) to only two categories (rather than around four in the past). Examples of MACE are cardiac death, nonfatal MI, nonfatal cardiac arrest, cardiogenic pulmonary edema, and complete heart block.

The categories are:

• Low risk (MACE < 1% risk) – cataract or plastic surgery procedures or those performed under local anesthesia.
   
• Elevated risk (MACE > 1% risk) – vascular surgery and any surgery that opens a body cavity.

The next step is to risk stratify preoperative patients using the revised cardiac risk index (RCRI). This is a well-studied, validated, and easy to use method to determine risk of perioperative MACE. It was modified from the original Goldman cardiac risk index to simplify the evaluation. Here’s the index:

The risk of cardiac death, nonfatal MI, and nonfatal cardiac arrest is as follows:

• 0 predictors = 0.4%
• 1 predictor = 0.9%
• 2 predictors = 6.6%
• > 3 predictors = >11%

An RCRI of 1 or 2 is associated with a lower risk of major cardiac complications.

The other piece of important information is determining the functional capacity of the patient. This is described in terms of metabolic equivalents (METS). One MET is equivalent to the resting oxygen consumption of a 40-year-old 70 kg male. Performing activities of daily living such as dressing = 1 MET. Examples of activities > 4 METS are climbing a flight of stairs, walking up a hill, or doing heavy housework such as scrubbing floors. Strenuous sports such as swimming, hiking, or skiing are > 10 METS.

Functional capacity can be estimated as follows:

• > 10 METS = Excellent
• 7-10 METS = Good
• 4-6 METS = Moderate
• < 4 METS = Poor

Here’s how to put this information together. Every patient should have a preoperative cardiac risk assessment, including the RCRI and functional status evaluation. A decision regarding further cardiac work-up can then be made based on this information.

If the surgery is emergent, then proceed with surgery regardless of the ability to work up the patient. Obviously, if the patient is going to die without the surgery, then the benefits of surgery outweigh the risks. It would be a good idea to have intensive care services and cardiology available just in case.

For patients in the other categories, evaluate the risk of perioperative MACE based on functional status, history and physical, and RCRI grade. If the surgery is low risk (MACE < 1%), such as doing foot/ankle surgery under local anesthesia, then no further testing is necessary and the surgery may proceed.

If the risk is higher (MACE > 1%), then a functional capacity should be determined. If the patient has a capacity > 4 METS or an RCRI of 1 or 2, then the surgery may proceed without further work-up.

If the risk is higher (RCRI is 3 or greater) and/or the functional capacity is poor (< 4 METS), then further testing such as cardiac stress or coronary angiography is indicated.

Let’s take a quick example to illustrate the use of this. My patient from above was a diabetic on insulin, with a history of coronary artery disease, and an elevated BNP (indicative of congestive heart failure). Having had a foot ulcer for some time, he had not walked recently. Nothing else was notable in his history or physical other than an S3 heart sound (again consistent with CHF). Since we were unable to determine his functional status and his RCRI was 3 (he had numbers 1, 2, and 4 in the risk index), he would have required testing such as an echocardiogram and coronary angiography. Of course, given the gas gangrene in his foot, his surgery was emergent, and surgery would have been best performed under local anesthesia if possible.

As my cardiology colleague said, every preoperative workup should include an RCRI evaluation. This won’t stop a patient from having a major cardiac event, but will help in a validated manner to predict that risk. And, if it does occur during surgery, the surgeon is protected from medicolegal risk by having appropriately evaluated the patient’s health. As I mentioned above, it is worth each of our time to read the ACC/AHA updated guidelines (or even just read the recommendations – it’s a very long document). Good luck on your next preoperative evaluation.

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