Cardiac surgery is one of the most challenging medical specialties. According to a study published in the Journal of Vascular Surgery, the attrition rate in cardiac surgery residency and fellowship programs is between 0.4% and 5.9%. Those who cope with burnout during training are often unable to simultaneously manage clinical and non-clinical duties later on, leading to a 31% deficit of cardiac surgeons nationwide.
While we cannot save cardiac surgeons’ from performing back-to-back surgeries, we can reduce their administrative burden with our detailed guide on CPT code 33533. Our expert tips can help you collect reimbursement on the first try.
CPT Code 33533 – Description
The Current Procedural Terminology (CPT) code 33533 is from the code range covering ‘Arterial Grafting for Coronary Artery Bypass’ procedures, as maintained by the American Medical Association (AMA). It reports a single-segment arterial grafting to divert the blood flow from a damaged vessel to the newly grafted one. The purpose of this procedure is to restore the heart’s normal functioning, improve blood circulation, and reduce symptoms like angina.
During the surgical procedure (which is performed under general anesthesia), the cardiologist takes a segment of a healthy artery from another part of the body, e.g., the chest or abdomen, and attaches it to the blocked/damaged coronary artery to bypass the blockage and reroute the blood flow. The procedure may take 3-6 hours to complete.
Medicare Part A covers CPT code 33533. The current reimbursement rate for coronary artery bypass grafting (CABG) is between $1,572.18 and $2,264.56, depending on MAC locality and facility.
Scenarios Where CPT Code 33533 is Applicable
Several clinical instances may necessitate the need to perform a single coronary artery bypass graft using a healthy internal mammary artery, and hence, the reporting of CPT code 33533. We have discussed a few such situations in detail below. Take a look!
To Treat Coronary Artery Disease (CAD)
Heart disease is the leading cause of death in the United States. According to the U.S. Centers for Disease Control and Prevention (CDC), every 33 seconds, one person dies because of heart disease. Coronary artery disease (CAD) is the most common heart disease in the country. Every 1 in 20 adults (5%) aged 20 and above have CAD.
It occurs when the arteries supplying oxygen-rich blood to the heart develop a blockage, e.g., plaque buildup. It restricts the blood flow to the heart, causing chest pain, shortness of breath, and even death. In 2021, nearly 375,500 people in the USA died because of CAD complications.
Cardiac surgeons harvest an arterial graft to bypass this blockage and restore blood circulation to the heart. They take a segment of a healthy internal mammary artery and attach one end to the aorta and the other to the damaged coronary artery to create an alternate channel for the blood to flow.
Now, consider that a 55-year-old man with CAD undergoes coronary artery bypass grafting. The surgeon performs a sternotomy (chest incision to cut open the sternum and access the heart), grafts arterial conduit to create a bypass, wires the sternum, and stitches the incision to indicate procedure completion. It restores blood supply to the heart, treating CAD. Hence, the cardiac surgeon will report CPT code 33533 on the claim form for rightful reimbursement against CABG.
To Bypass Blockage in the Left Main Coronary Artery (LMCA)
The left main coronary artery or left coronary artery branches from the aorta and supplies blood to the left myocardium, including the left ventricle and atrium. Its blockage can cause a heart attack and death. Therefore, immediate medical intervention in the likes of CABG is necessary.
Imagine that a 60-year-old patient with a history of heart attack and a blocked LMCA is rushed to the operating room for a coronary artery bypass grafting. The cardiac surgeon performs the procedure on his left coronary artery, successfully bypasses the blockage to restore normal blood flow to the left side of the heart, and reports the surgery with CPT code 33533.
To Treat Restenosis After an Angioplasty
Restenosis (re-narrowing of the artery) can occur within the first few months of an angioplasty. If the blockage develops in the coronary artery, supplying oxygenated blood to the heart, it requires immediate medical attention to prevent fatal heart attacks. Hence, a coronary artery bypass grafting is performed to create an alternate channel for the blood to flow and restore the normal functioning of the heart.
Think of a 45-year-old woman who underwent angioplasty 2 years ago to remove a blockage in her coronary artery. However, due to her genetics and lifestyle, the blockage reappears, causing chest pain and shortness of breath. Her cardiologist advises a more invasive procedure this time, CABG, to bypass the blockage and reduce the symptoms. Therefore, the billing team will report CPT code 33533 for reimbursement.
Applicable Modifiers for CPT Code 33533
Modifiers are two-digit codes that are appended to the CPT and HCPCS codes and provide supplemental information to the insurance payer, such as who performed the procedure and under what circumstances. Some modifiers that are commonly appended to CPT code 33533 for added details are as follows:
Modifier 22
Modifier 22 indicates increased procedural services. For example, if the bypass creation from a grafted coronary artery took more time and effort than the standard, modifier 22 may be applied to CPT code 33533 to explain this and for higher reimbursement.
Modifier 51
Modifier 51 highlights multiple non-E/M procedures performed during the same surgical session on the same patient by the same healthcare provider. So, if another procedure was performed prior to or subsequent to the CABG during the same session, modifier 51 will be appended to CPT code 33533 to indicate this.
Modifier 53
Modifier 53 is appended to CPT code 33533 to explain that anesthesia was administered and the procedure was started but discontinued midway due to extenuating circumstances threatening the patient’s well-being, such as high blood pressure. Using this modifier will help you collect 50% of the allowed reimbursement amount.
Modifier 59
How is modifier 59 different from 51? Modifier 59 explains that CAGB, covered by CPT code 33533, is separate and distinct from other procedures performed on the same day. It is used to distinguish two services that are commonly reported together (bundled under a single payment). However, you must avoid overusing modifier 59 if modifiers X{EPSU} are more appropriate.
Modifier 62
Modifier 62 is appended to indicate that two surgeons were involved in the coronary artery bypass grafting. Both served as the primary surgeons and performed distinct parts of the procedure based on their specialties. For instance, one surgeon was in charge of artery harvesting, while the other handled bypass creation.
Modifier 66
However, if more than two surgeons were involved in the open-heart procedure, modifier 66 will be appended with CPT code 33533 to indicate a team of surgeons. It usually happens when the procedure becomes more complex than usual, and collaborative effort is required to ensure its success.
CPT Code 33533 – Billing & Reimbursement Guidelines
If you want your insurance claims to get approved on the first attempt, accurate coding is not enough. You must also implement billing best practices to ensure clean, compliant, and error-free claim filing. Here are some billing guidelines and reimbursement requirements specific to CPT code 33533.
Ensure All Components of CPT Code 33533 were Performed
Remember, you can only report CPT code 33533 if one segment of a coronary artery was grafted to bypass a blockage because CPT code 33534 covers two segments of coronary artery bypass grafting.
Second, the arterial conduit must be obtained from a healthy internal mammary artery (such as the abdomen or chest). Third, one end of the graft must be attached to the aorta and the other to the damaged blood vessel to create an alternate pathway for the blood to flow.
Pair with the Correct Diagnosis Code
You must support CPT code 33533’s usage by pairing it with the most accurate ICD-10-CM diagnosis code to emphasize the procedure’s medical necessity. For example, you can use:
- I20.1 – for angina pectoris with documented spasm
- I20.2 – for refractory angina pectoris
- I20.9 – for angina pectoris, unspecified
Maintain Complete Documentation
Insurance payers also need complete and accurate documentation to assess the medical necessity of the procedure and finalize the reimbursement rate. Your supporting documentation must include diagnostic test reports, referral letters, clinical notes, surgical notes, the patient’s complete medical history, and a pre-authorization letter (if required).
Follow Medicare’s NCCI Policy Manual for Combined Arterial-Venous Bypass
According to Medicare’s National Correct Coding Initiative (NCCI) Policy Manual, Chapter V, you can report CPT code 33533 with any of the CPT codes within the range 33517-33523 if a combined arterial-venous bypass surgery was performed. Moreover, you must use the code that most comprehensively describes the procedure performed.
Adhere to Payer-Specific Rules
You must also be mindful that Medicare, Medicaid, and each commercial payer have specific rules and guidelines when it comes to billing for a coronary artery bypass grafting surgery. Therefore, ensure that you have thoroughly read the contract, Medicare Administrative Contractors’ (MACs’) local coverage determination, and payers’ billing manuals before creating and submitting claims for CPT code 33533.
Summary
Before we leave you with the ultimate solution for all your coding conundrums, let’s quickly revisit what we learned in this guide. We explained that CPT code 33533 covers an open-heart surgery to bypass a blockage in the coronary artery. A segment of a healthy artery is grafted or attached to the damaged one to restore the supply of oxygenated blood to the heart.
We also discussed some practical scenarios for the appropriate usage of CPT code 33533, such as to treat CAD and restenosis after an angioplasty and to bypass a blockage in LMCA. When needed, you can append modifiers 22, 51, 53, 59, 62, and 66 for fair reimbursement.
Apart from ensuring documentation completeness and policy compliance, you must consider outsourcing medical coding to professionals like MediBillMD. Their comprehensive cardiology billing services include CPT coding at the hands of AAPC-certified medical coders, boosting your clean claims rate up to 98%.
