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.