In our last article, we discussed how to code percutaneous procedures in arteriovenous (AV) fistulas and grafts. If you haven’t had a chance to read part 1 of this article, I encourage you to do so first to gain the most benefit from the information below: AV Fistula and Grafts Part 1.
Today, we are going to take a look at procedures that are performed in AV fistulas and grafts through an open approach. We will also look at hybrid procedures (cases where part of the procedure is performed through an open approach and part through a percutaneous approach). These procedures present unique challenges due to guidelines that bundle some of the percutaneous procedure codes to the open procedure codes – more on that in a moment.
Open Approach Codes
Let’s start by looking at the three key procedure codes for open approach to procedures in an AV fistula/graft:
CPT 36831 is reported for open thrombectomy of an arteriovenous fistula or graft. This procedure involves making an incision over the AV fistula/graft, creating an opening into that fistula or graft (often referred to as a fistulotomy or graftotomy respectively), and removing thrombus from the graft. Thrombus may be removed directly by grasping thrombus with tools such as forceps or even by “finger extracting” (freeing thrombus that is located right at the opening into the fistula/graft with the surgeon’s finger). Alternatively, thrombus may be removed further from the opening into the fistula/graft by passing catheters such as Fogarty catheters to remove the thrombus. When the physician has removed all of the thrombus he/she is able to remove, they close the opening in the graft and then close the incision.
CPT 36832 is reported for open revision of an arteriovenous fistula or graft without thrombectomy. A revision of an AV fistula/graft is a repair that allows blood to flow through the AV fistula/graft more effectively. There are many different complications that can occur in an AV fistula/graft including but not limited to stenosis, a pseudoaneurysm, or a non-maturing fistula/graft. Because a revision of an AV fistula/graft may treat many different complications in different parts of the dialysis circuit, the revision can take many different forms. Below are some examples of different revisions that are commonly performed by vascular surgeons:
- Taking down the existing connection between the artery and vein (known as the anastomosis) and recreating a new connection between the artery and vein.
- Cutting out an area of stenosis in the graft/fistula and replacing that area with a piece of graft harvested from the body or a synthetic graft (graft that is not from the patient’s body). This procedure is sometimes referred to as an “interposition graft.”
- Creating an open incision over accessory veins that are drawing blood flow away from the AV fistula/graft and causing poor blood flow then banding (i.e., narrowing) those veins to allow more blood flow into the AV fistula/graft.
- Making a graftotomy and inserting a catheter with a balloon to open up an area of stenosis.
- Making an incision to open the anastomosis then placing a patch such as vein or synthetic material to cause the vessels forming the anastomosis to remain wide open. This procedure is sometimes called a “patch angioplasty.”
CPT 36833 is reported for open revision of an arteriovenous fistula or graft with thrombectomy. To put it simply, this procedure involves the work of CPT 36831 and 36832 combined.
Coding Examples
Now that we’ve looked at some key definitions and the open approach codes, let’s look at some examples of procedures and the appropriate coding for each example.
Example #1: After sterile prep and drape, an incision was made over the left arm AV graft. A graftotomy was created a few centimeters from the arterial anastomosis. A Fogarty catheter was threaded through the graft towards the venous side and a long string of thrombus was retrieved. After retrieval, the flow in the graft significantly improved. A few more passes of the Fogarty were made throughout the entire venous outflow to the level of the axillary vein. Some additional short strings of thrombus were retrieved from the graft. Graftotomy was then closed followed by layered closure of the left arm incision. Patient tolerated the procedure well.
Answer example #1: In the note above, the phrases highlighted in bold help us to understand the approach to the procedure, the phrases underlined let us know where the surgeon was working, and the phrases in italics let us know what procedures were performed once the surgeon has entered the graft. Beginning with the the approach, we first see that an “incision was made” and “a graftotomy (again an opening into the graft) was made.” This confirms our open approach. From there, I have underlined the phrase “left arm AV graft” to make it clear the surgeon is accessing an arteriovenous graft in the left arm through this open approach. In the next sentence, the surgeon “uses a Fogarty catheter” to enter the graft and threads it “through the graft” towards the venous side (the end of the the graft where it connects to the vein forming the arteriovenous graft). He then “retrieves (aka removes) a long string of thrombus.” You may see surgeons use this word “string” to refer to thrombus. This term means that there are multiple areas of thrombus all clotted and connected together. By telling us whether the string is short or long, the surgeon is giving us a picture of how much thrombus is being pulled out of the graft. The surgeon notes the flow in the graft has improved after pulling out that initial string of thrombus, but decides to keep going with the procedure to ensure he’s cleared the graft of all clot. So he makes “a few more passes with the Fogarty catheter” and threads the catheter this time up through the entire venous outflow to the level of the axillary vein. I talk about venous outflow and the extent of the peripheral segment of an AV fistula or graft in part 1 of this article so feel free to go back to that article for a refresher on these terms if need be. He removes “some additional short strings of thrombus” with the additional passes of the Fogarty catheter. He then concludes the procedure is complete and closes the graftotomy and then the arm incision.
This documentation supports CPT 36831.
Example #2: After sterile prep and drape, an incision was made exposing the right arm AV fistula. A fistulotomy was created at the anastomosis. I extended my incision longitudinally until the entire anastomosis was widely opened. Through a separate incision, I harvested a small piece of saphenous vein for use as a vein angioplasty. I then sutured this patch in place at the arteriovenous anastomosis. Good flow was observed, confirming a successful procedure and a widely patent anastomosis. The incision was closed in layers.
Answer example #2: Again in the note above, the phrases highlighted in bold help us to understand the approach to the procedure, the phrases underlined let us know where the surgeon was working, and the phrases in italics let us know what procedures were performed once the surgeon entered the fistula. Beginning with the approach, we first see that an incision was made and a fistulotomy (again an opening into a fistula) was made. This confirms our open approach. From there, I have underlined the phrase “right arm AV fistula” to make it clear the surgeon is accessing an arteriovenous fistula in the right arm through this open approach. In the next sentence, the surgeon “extends the incision longitudinally (or lengthwise) until the entire anastomosis was widely opened.” He then describes harvesting a piece of the saphenous vein (a superficial vein in the leg often used for patches or bypass grafts during vascular procedures). He then cuts a small patch from the saphenous vein and places that patch at the arteriovenous anastomosis and confirms the anastomosis is “widely patent” (i.e., wide open and allowing good blood flow).
A patch angioplasty is a type of revision of a graft, and no thrombectomy is performed. Therefore, this documentation supports CPT 36832. The harvest of the saphenous vein to create the patch is included in CPT 36832 so no additional code will be assigned for the work of the vein harvest.
Hybrid Procedures
So far, we have discussed cases with percutaneous procedures performed in AV dialysis circuits and open procedures performed in AV dialysis circuits. What happens, though, when part of the procedure is performed through an open incision and another part of the procedure is performed through a percutaneous approach? This type of procedure which I refer to as a “hybrid procedure” happens more often than you would think.
Peripheral Segment Procedures
The CPT guidelines in the section of the manual that precedes CPT codes 36901-36909 state that CPT codes 36901-36906 (which include the code for a diagnostic fistulogram and all interventions in the peripheral segment of the graft) may not be reported with CPT codes 36831-36833.
I’ve seen this guideline about not reporting open and percutaneous interventions together in the peripheral segment of the AV dialysis circuit cause a lot of confusion for coders. For example, I’ve seen many cases where the surgeon performs an open incision over the AV graft followed by a graftotomy and removal of thrombus, but then does a separate percutaneous access into the axillary vein and inserts a balloon to perform angioplasty of an area of stenosis. Everything we have learned about AV dialysis circuit interventions so far tells us that the open thrombectomy should be coded with CPT 36831 and the percutaneous balloon angioplasty should be coded with 36902, but again, the CPT guidelines say you may not report these two codes together. If you check your NCCI edits, you will see a bundling edit as well. So how do we give the surgeon credit for all the work he/she performed without violating any coding rules? In this case, we would actually report CPT 36833 for the combined work of the thrombectomy and the angioplasty to open up the area of stenosis. While the angioplasty itself is performed through a percutaneous approach, it is a type of revision (since it is a procedure performed to improve blood flow in the AV dialysis circuit). We can code it as an open revision since there is an open incision and graftotomy a little further down the arm to perform the thrombectomy and both procedures are occurring in the peripheral segment of the same AV dialysis circuit. Since we can “count” that open incision as part of our revision (i.e., our balloon angioplasty) and since the surgeon also performs an open thrombectomy of the graft, this documentation would support CPT 36833.
Central Segment Procedures
One final rule to keep in mind with hybrid procedures is that, while the CPT guidelines prevent you from coding 36901-36906 with 36831-36833, the guidelines do allow you to report central segment percutaneous procedures (36907-36908) with the open revision and thrombectomy codes (36831-36833). The reason the rules are different here is because the open revision and/or thrombectomy is occurring in the peripheral segment while the percutaneous angioplasty/stent is occurring in the central segment. So we aren’t reporting two procedures performed through different approaches in the same part of the AV dialysis circuit.
To give an example, if a surgeon performed the patch angioplasty of the arteriovenous fistula described in example #2 under “open procedures” earlier in this article and also made a separate percutaneous access into the subclavian vein and placed a stent in an area of stenosis, we could report both CPT 36832 and CPT 36908.
While these procedures can be challenging to code and there are many variations due to the unique challenges and complications that arise with long-term dialysis, I hope the tips and examples in these articles will help you code these procedures with confidence.
