Practice Perfect 909
The Pod Periop Medical Management Series # 3:
Getting to the Heart of the Matter Part 1 - Testing

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Jarrod Shapiro, DPM, FACFAS, FACPM

Practice Perfect April 23, 2024

Now that we’ve gone through the basic principles of perioperative testing in our first two editorials, namely, to conduct a proper preoperative history and physical and to then order testing based on that H&P (rather than shot-gunning a large number of tests that are unlikely to be helpful), we can now move on to the specifics. We’ll cover future topics such as diabetes, rheumatologic disease, and others, but let’s start with the most important perioperative issue: preventing cardiac complications.

I describe this as “most important” because cardiac disorders are common and more likely to hurt or kill patients in the perioperative period. Today, we’ll focus on the preoperative evaluation, ie testing. Next week we’ll discuss medication management. Let’s get to it.

How Important Is the ECG?
It seems everyone having surgery gets an ECG. I once even had a 12-year-old with an ankle fracture who had an ECG ordered by the medicine service in the hospital! To stay true to our theme in the prior two issues, ECGs come back abnormal in 4.6-31.7% of preoperative patients, leading to a change in management of 0–2.2% of patients.¹ Clearly, ECGs have a weak perioperative predictive value. Experts now recommend not routinely ordering ECGs preoperatively unless there is a systemic disease with a cardiac component (diabetes and rheumatoid arthritis are two examples), emergency surgery is occurring (we often are not able to fully glean the medical history in some cases), and in certain ages.

Men older than 40-years and women older than 55-years and others with cardiac disease should have a preoperative ECG.

Now, keep it firmly in mind that if you order an ECG, and it returns with abnormalities, then you should know how to read that ECG and be ready to act on it, such as with referral to cardiology for further assessment. Reading and interpreting an ECG is outside the scope of this editorial.

Shining the Light on Limb Loss

Daniel Ferreras, DPM, FACFAS, AAWC

Chief Podiatrist ? PAVE Coordinator
Carl Vinson, VA Medical Center

This lecture focuses on how we, at the Carl Vinson VA, have incorporated some of the latest wound healing technologies into our PAVE Program to help heal wounds, improve patient outcomes during wound healing, and help reduce the number of amputations at our facility.

Available Credits: CPME 0.5

Cardiac Clearance: No Such Thing
In the past, it was common to send a patient to cardiology, requesting “clearance”, but this is no longer the case. It is now the standard of care for healthcare professionals to stratify patients by cardiac risk. We should also understand that cardiologists will no longer state “cleared for surgery” in their notes. Rather, they will state a calculated risk. It’s up to the surgeon to determine just how safe the patient is. The information we’ll discuss below comes from the most current ACC/AHA guidelines on perioperative cardiac evaluation in non-cardiac patients.² This is a very comprehensive document, and I strongly suggest reading it carefully. Unfortunately, a newer set of guidelines is not currently available.

Don’t ask for cardiac clearance. Instead, request cardiac risk evaluation.

There are a number of risk calculators today, but there are a few methods that are relatively easy to use and interpret. What are we at risk for exactly? We’re looking for MACE or Major Adverse Cardiovascular Events: myocardial infarction, congestive heart failure, complete heart block, pulmonary edema, ventricular fibrillation, or asystole.

First, it’s important to determine the level of risk for the surgery itself. In general, high-risk procedures have a > 1% risk of adverse events while low risk procedures have a risk < 1%.² For podiatrists, elective procedures taking less than two hours are low risk, while longer cases such as Charcot realignment arthrodesis or emergent cases such as incision and drainage and amputations should be considered high risk.

Functional Capacity: How High Can You Go?
Next, we can start our risk assessment by simply asking the patient about their activities since certain levels of activity ability are correlated with an increased or decreased risk of MACE. The table below refers to the Duke Activity Scale.³ Patients are asked for their ability to do the various activities, and the number of METs or metabolic equivalents. One MET would be one’s oxygen consumption at rest. To get technical 1 MET = 3.5mL O2/Kg/Min.

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Less than 4 METs is considered poor functional capacity and a greater increased risk for MACE while greater than 4 METs is considered moderate functional capacity and at lower risk for perioperative MACE. To make this evaluation simple, I ask my preop patients two questions: Can you climb 2 flights of stairs without running out of breath? How many blocks can you walk? Reilly and colleagues found in a population of 600 patients, the risk of MACE was inversely proportional to the number of flights of stairs one could climb and the number of walkable blocks.⁴

Functional capacity reported as > 4 METs correlates with a low risk of perioperative MACE.

Using the RCRI to Evaluate Perioperative Cardiac Risk: An Easy Tool
The Revised Cardiac Risk Index (RCRI) is another popular tool that may be rapidly employed during the preoperative evaluation to help determine if further cardiac evaluation should be performed. The table below lists the six factors and their associated risk of perioperative MACE.

One simply adds the number of factors, and if a patient has one or less factors, they are at low risk for MACE, while 2 or more have increased risk and should be referred for further testing. When performing my preoperative history and physical evaluation, I document these findings and hold elective surgeries when patients have a score of 2 or greater, referring these patients to cardiology and their primary care physicians.

An RCRI > 1/6 warrants referral to cardiology for further examination.

To wrap this up, remember that ECGs have a low predictive value for major cardiac events during surgery, functional capacity evaluation with > 4 METs is safe for surgery, and using the RCRI with value > 1 strongly urges for further evaluation. Next week, we’ll discuss in a high-yield manner how to handle the medications used in the cardiac patient to prevent medication-induced perioperative complications.

Best wishes.

Jarrod Shapiro, DPM
PRESENT Practice Perfect Editor
[email protected]

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