Arteriovenous (AV) dialysis access (AV fistula, AV dialysis graft) interventions are intended to restore and/or maintain functional patency of the AV dialysis access. These procedures encompass a number of percutaneous or open surgical procedures. Indications for interventions on an AV dialysis access include compromised flow with threatened occlusion, recent thrombosis of AV dialysis access, and management of structural abnormalities such as pseudoaneurysms. Interventions are performed on AV dialysis fistulas and grafts in order to restore adequate flow, to preserve the access' function, and avoid the need to create a new AV access. Fistulae which are not maturing as expected are also evaluated and treated with percutaneous interventions.
Percutaneous interventions to enhance or re-establish patency of a hemodialysis AV access have proven useful in extending the life of the access, reducing the need for open repair, reconstruction or replacement. The longevity and quality of life of the end stage renal dialysis (ESRD) patient are improved. This policy documents acceptable indications and limitations of coverage and other CGS requirements for dialysis access maintenance services.
Definitions:
(AV) dialysis access: A surgically-created communication between an artery and a vein used for vascular access for hemodialysis. The communication may be a direct fistula (AV fistula) (e.g. Brescia Cimino fistula), brachiocephalic fistula or an interposed conduit (AV graft) (e.g. brachiocephalic loop graft). The conduit may be an autogenous vessel or synthetic material.
Percutaneous transluminal angioplasty (PTA): An invasive procedure which, when successful, enlarges a narrowed vascular lumen. Typically, a balloon-tipped catheter is introduced percutaneously into the narrowed vessel. The balloon is inflated at the site of vascular stenosis, stretching the vessel and opening the lumen to restore adequate flow through the vessel. The balloon is removed after angioplasty.
Thrombolysis: Pharmacologic and/or mechanical dissolution of a thrombus or blood clot.
Infusion: Continuous intravascular administration of a medication containing solution lasting longer than sixty (60) minutes. Bolus injections are not considered infusions, regardless of the time required to inject the solution.
Dialysis Access: An arteriovenous dialysis access.
Embolization/ligation of collateral branch veins: AV fistulae depend on a single outflow vein to carry the flow, so that this vein can enlarge to the point it is easily punctured and has brisk flow. If branch veins are large enough to siphon off a significant amount of flow, no single vein will enlarge enough to be used. Closing off the side branches may allow the outflow vein to mature. The side branches may be closed off surgically by tying off the branches, or may be closed off by placement of occlusive material into the side branch through a catheter (embolization).
Indications:
Evaluation of Dialysis Access Dysfunction - Clinical Findings
Typically, the clinical examination provides adequate information to determine whether there is hemodynamically significant dialysis shunt dysfunction. The following clinical findings are considered diagnostically specific and appropriate indications to initiate therapies to re-establish physiologically appropriate flow in the dialysis fistula.
Venous outflow impediment clinical findings include:
- elevated venous pressure in the AV dialysis access;
- elevated venous/arterial ratio (static venous pressure ratio - above 40%);
- prolonged bleeding following needle removal;
- inefficient dialysis;
- recirculation percentage greater than 10-15%;
- development of pseudoaneurysm(s);
- swelling of the extremity, face or neck;
- development of large superficial collateral venous channels;
- loss of "machine-like" bruit, i.e., short sharp bruit; and/or
- abnormal physical findings, specifically pulsatile graft/fistula or loss of thrill.
Arterial inflow impediment clinical findings include:
- low pressure in graft even when outflow is manually occluded;
- ischemic changes of the extremity (steal syndrome); and/or
- diminished intra-access flow.
Evaluation of Dialysis Access Dysfunction – Diagnostic Tests
If a stenosis is suspected clinically, typically a diagnostic study is required to determine the level(s) of disease and to formulate a plan for treatment. This is most commonly accomplished with a fistulagram (36901-36906).
- Diagnostic fistulagram – with puncture of the AV dialysis access with needle or catheter placement, and diagnostic angiography of the entire AV dialysis access circuit, from the arterial anastomosis through the central veins and cava, which is performed to identify the area or areas of narrowing or occlusion that are creating flow problems for the AV dialysis access (36901-36906). This includes visualization and examination of the vena cava.
- Diagnostic fistulagram - without directly puncturing and/or catheterizing the AV dialysis access. For instance, a fistulagram may be performed through an existing needle or sheath or via an injection of a vessel other than direct puncture of the AV dialysis access (e.g., injection of the subclavian artery through a femoral arterial puncture) (CPT code 36901-36906).
- Diagnostic non-invasive vascular studies (CPT code 93990) performed to evaluate an AV access are reasonable and necessary in the presence of signs and symptoms of impending failure of the access sites and when the result may impact the clinical course of the patient.
Percutaneous AV Dialysis Access Maintenance and Salvage
Percutaneous AV dialysis access declotting, maintenance, or re-establishment of appropriate and adequate flow may encompass any of the procedures listed below. These need not all be performed on every dysfunctional access, but each may, under unique circumstances, be considered reasonable and medically necessary.
Mechanical and/or pharmacologic maneuvers to promote dissolution, fragmentation and/or removal of obstructing thrombotic materials (36904-36906) - includes all work necessary to remove thrombus from the AV dialysis access, including mechanical thrombolysis, mechanical removal of thrombus, as well as all pharmacological means of removing thrombus from the dialysis access (including bolus, infusion, pulse-spray etc.).
Percutaneous transluminal angioplasty (PTA): - PTA of the AV dialysis access and/or afferent and efferent vessels is not necessary for all poorly functioning AV dialysis accesses. Coverage will be considered if there is documentation supporting the presence of residual, hemodynamically significant stenosis, generally >/50 percent of the vessel diameter. There must be clear documentation of the site and extent of any hemodynamically significant stenosis. This documentation may be subjected to medical necessity review.
Venous PTA – PTA is typically necessary to treat stenoses. The stenosis is most commonly found at the level of the venous anastomosis for synthetic graft accesses, but can be found anywhere from the arterial inflow through the vena cava. Multiple stenoses are found in a significant percentage of patients. When the patient presents with a thrombosed AV access, PTA is commonly needed after the acute thrombus has been removed. The AV access often occludes because of decreased flow due to an underlying narrowing, and this narrowing must be opened in order to prevent acute re-occlusion.
For purposes of reporting, the AV dialysis access is considered a single vessel from the arterial anastomosis through the axillary vein. All PTA done within this segment of vessel is coded as CPT codes 36902, 36905, 36907, 37247-37249 used once no matter how many focal lesions are treated within this segment. All PTA within the arteriovenous dialysis access “vessel” would be coded as a single PTA, regardless of the number of stenoses treated within this segment.
For AV dialysis native fistulae, the “vessel” is defined as the inflow artery at the AV anastomosis, the AV anastomosis, and the outflow vein to the level of the axillary vein. For AV dialysis grafts, the “vessel” is defined as the inflow artery at the arterial anastomosis, the arterial anastomosis, the entire length of the graft, the venous anastomosis, and the venous outflow to the level of the axillary vein. All PTA done within these defined segments would be coded as a single angioplasty.
Angioplasty may be coded a second time if a separate stenosis is treated in a central vessel (e.g., axillary, subclavian, brachiocephalic vein or artery, or SVC). The site of, and need for, separate stenosis treatment should be clearly documented. If central venous stenoses are treated, the venous angioplasty codes 36902, 36905, 36907, and 37247-37249 should be used once to describe central venous angioplasty, even if more than one discrete central lesion must be treated.
There is one clinical situation that is an exception to the above. Arterial PTA may be necessary if there is an inflow arterial stenosis that is limiting flow through the dialysis access. If a PTA is performed at the arterial anastomosis of an AV dialysis access, it could be coded as 36902, 36905, 36907, and 37246-37249. In this instance, all PTA done within the AV dialysis access “vessel” would still be coded as a single PTA but would be coded with the arterial codes (36902, 36905, 36906, 37246-37249) instead of the venous codes (36902, 36905, 36907, 37247-37249), and the venous codes would not be used for any other angioplasty performed within the AV dialysis access vessel.” Arterial PTA codes are not submitted for simple removal of the arterial plug when performing a declot procedure.
Open Surgical AV Dialysis Access and Maintenance
- Open surgical therapy for thrombosed or impaired AV dialysis access utilizes direct open access to the conduit and contiguous vessels. Mechanical fragmentation and surgical removal of occlusive thrombotic material is effected under direct visualization. Adjunctive thrombolytic pharmacotherapy may be employed. Residual vascular stenoses or obstructive lesions are removed and corrected using standard vascular surgical techniques (e.g., CPT codes 36831, 36832, 36833). Angiography is adjunctively employed, when appropriate and medically necessary, to assess the functional integrity of afferent and efferent vessels remote from the surgical field.
- Stents - Subject to FDA approval of specific devices, stents are covered if used as a last resort to salvage a graft or fistula. Placement of an intravascular stent (e.g. CPT codes 37205-37206) and the associated supervision and interpretation (CPT code 75960) may be appropriate in selected clinical scenarios. The following clinical scenarios are examples where a stent may be considered for payment:
- PTA induced rupture;
- graft salvage (e.g., PTA is unsuccessful due to elastic recoil, stenosis has recurred or less than 3 months);
- central veins stenosis or occlusion; and
- aneurysm or pseudoaneurysm is present.
Stents used under experimental protocols are not covered unless used within the Category B Investigational Device Exemption (IDE) protocol.
Limitations:
When diagnostic non-invasive vascular studies are performed to evaluate an AV access on a routine basis in the absence of signs and symptoms, the services are considered monitoring, and are not separately covered by Medicare.
In the absence of clinical findings suggesting the need to re-establish appropriate flow in a dialysis fistula, it is seldom reasonable and necessary to perform diagnostic angiography or sonographic confirmatory studies as part of the decision to treat (i.e., CPT codes 75710, 75820, 93990).
Venography codes may be reported in conjunction with AV dialysis access procedures.
Services performed for percutaneous interventions to treat total occlusion of graft due to thrombus of more than one year in duration will be considered not reasonable and not medically necessary.
Angioplasty of vessels not documented to be stenosed significantly by angiography or ultrasound will be considered not medically necessary.
Dilation of the graft anastamotic site will be considered either arterial or venous, but not both.
Use of a device that is not FDA approved will be considered investigational and not medically necessary.
Revision procedures that are not for repair and/or maintenance of an existing fistula, but are performed as part of a planned staged procedure to create a new fistula are not subject to the coverage provisions and limitations of this LCD.
