When becoming a doctor, med students take an oath to “First Do No Harm.” A doctor’s priority is always to do no additional harm to their patient when treating them. This especially applies when their patient is getting a major surgery. Part of that oath to do no harm is to properly evaluate their patient to make sure they are fit for surgery. This includes getting cardiac clearance. Cardiac clearance, unlike the name suggests, is not giving medical clearance or guaranteeing a positive outcome, but rather, the risks of noncardiac surgery on a patient are considered and evaluated. The doctor giving this clearance makes recommendations and evaluates the management and risk of cardiac problems arising from such surgery. So, what is the process of getting this clearance, and what does it mean for the outlook of your surgery?
When Is It Necessary?
The guidelines for when cardiac clearance is necessary are based on the guidelines published by the American College of Cardiology (ACC) and the American Heart Association (AHA) in 2014 (onlinejacc.org/content/64/22/e77). According to these guidelines, cardiac clearance has multiple purposes:
- “Assessment of Pre-operative Risk”
- “Determination of the Need for Changes in Management”
- “Identification of Cardiovascular Conditions or Risk Factors Requiring Longer-Term Management”
Cardiac clearance is necessary for the following types of patients:
- Patients undergoing plastic surgery
- Patients with complex medical history
- Patients with history of cardiac disease, vascular disease, stroke, heart stents, etc.
- Patients with hypertension, obesity, diabetes, COPD, sleep apnea (these are also known as co-morbidities)
- Patients undergoing high-risk surgical procedures
Low Risk Versus Elevated Risk
Cardiac clearance will provide a result of low risk or elevated risk. “Low risk,” according to the ACC/AHA guidelines, is classified when “the combined surgical and patient characteristics predict a risk of a major adverse cardiac event (MACE) or infection of less than 1%.” Low risk puts very little strain on the patient’s heart, and the risk is minimal. Examples of low risk procedures would be cataract removal, cosmetics surgeries, and surgeries involving the hands or feet. The further away the surgical site is from the heart, the lower the risk.
“Elevated risk” shows that “the combined surgical and patient characteristics predict a risk of a major adverse cardiac event (MACE) or infection of 1% or higher.” These procedures can be altered to make them less of a risk, such as changing the surgical site. Examples of elevated risk procedures would be surgeries involving the spine, skull, chest, abdomen, or replacing a large joint such as a knee.
(Figure 1- From the 2014 ACC/AHA Guidelines on Cardiac Clearance)
The process of cardiac clearance involves several steps. When achieving cardiac clearance, the medical professionals will assess the type of surgery, age and medical history of the patient, cardiac risk factors associated with both the patient and the surgery, and the patient’s exercise tolerance. Initially, the patient is asked a “Patient Pre-operative Questionnaire.” A physical exam is also given, as well as an echocardiogram (ECG). The ECG will identify if the patient has any serious cardiac conditions or disorders, such as arrhythmias, Cardiac Artery Disease, etc. Depending on the disease severity, stability, and any prior treatment the patient received, they may also need additional test such as the following:
- Chest X-Ray
- Non-invasive Cardiac Testing
- Pacemaker/ICD Testing
- Pulmonary Function Testing
- Stress Testing
- Sleep Study
If the patient is shown to have cardiac risk factors or the procedure is considered elevated risk, the ACC/AHA guidelines recognize the above referenced chart as the path to cardiac clearance (Figure 1).
Standardized Risk Scores
There are three main standardized risk score indexes that are used to measure cardiac risk:
- RCRI- Revised Cardiac Risk Index
- This index is validated by plenty of studies and professionals and is very easy to use. Made in 2011, this index is supported by the latest ACC/AHA guidelines, and measures 6 predictors of risk. Only one of those predictors relates to the type of surgery. Patients with 0-1 predictors of risk are considered to have a low risk of MACE. Those with >2 predictors of risk are considered to have an elevated risk of MACE.
- This index is only validated by one, rather large study. However, it is also supported by the latest ACC/AHA guidelines, measures 21 variables of the patients (age, sex, BMI, etc.), and aims to define the upcoming surgery as an “emergency” or not.
- The third index is easy to use but is not supported by the latest ACC/AHA guidelines. This index is not commonly used.
What Are My Risks?
The cardiac risks that can arise from non-cardiac surgery include, but are not limited to the following:
- Coronary Artery Disease (CAD)
- Post-operative Hypertension
- Valvular Heart Disease
- Heart Failure
How to Thwart Risks
So, how can you thwart these risks? Having cardiac clearance prior to any surgery is very important. However, before you should need any surgery, keeping your heart healthy is key to an overall health that cannot be overstated. CT Cardio offers (but are not limited to) the following services that can assess your heart health:
- Stress Testing
If you would like to learn more about the cardiac clearance process, or about your heart health, contact the professionals at CT Cardio. They are ready to serve you and lead you on a path to cardiac wellness!