Summary Of Evidence

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Analysis of Evidence

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Overview
Non-invasive peripheral venous vascular studies utilize ultrasonic Doppler and physiologic studies to assess the irregularities in blood flow in the venous system. Noninvasive peripheral venous vascular studies include the patient care required to perform the studies, supervision of the studies, and interpretation of study results, with copies for patient records of test results and analysis of all data, including bi-directional vascular flow or imaging when provided.

Diagnostic tests must be ordered by the physician who is treating the beneficiary and use the result in the management of the beneficiary’s specific medical problem. Services are deemed medically necessary when all of the following conditions are met:

1. Signs/symptoms of ischemia or altered blood flow are present;
2. The information is necessary for appropriate medical and/or surgical management;
3. The test is not redundant of other diagnostic procedures that must be performed.

Definitions:
Duplex Scans: Duplex combines Doppler and conventional ultrasound, allowing the structure of blood vessels, how the blood is flowing through the vessels, and whether there is any obstruction in the vessels to be seen. Color Doppler produces a picture of the blood vessel, and a computer converts the Doppler sounds into colors overlaid on the image, representing information about the speed and direction of blood flow. Using spectral Doppler analysis, the duplex scan images provide anatomic and hemodynamic information, identifying the plaque, occlusions and incompetent veins. Duplex scans are in real-time.

Physiologic Studies: Functional measurement procedures which include Doppler ultrasound studies, blood pressure and physiologic waveforms, segmental pressure measurements, blood pressure measurements, transcutaneous oxygen tension measurements, exercise testing, and/or plethysmography. These studies do not involve imaging.

Doppler Ultrasound uses reflected sound waves called physiologic waveforms to evaluate the blood as it flows through a vein. The waveforms bounce off blood cells in a motion that causes a change in the pitch of the sound, called the Doppler effect. These can be measured at a single level, or at segmental (various) limb levels. An audible sound is created and recorded by either an analog recorder or spectral analyzer. Spectral analysis separates the signal into individual components and assigns a relative importance. If there is no blood flow, the pitch does not change. The receiver detects the shift.

Exercise testing can be used to analyze the functional significance of vascular disease by reassessing the blood pressure with the Doppler stethoscope after completion of an appropriate amount of stress testing.

Plethysmography is a measurement of the volume of an organ or limb section, or flow rate, in response to the inflation and deflation of a BP cuff. Volume measurement procedures include air, impedance or strain gauge methods.

I.  Peripheral Venous Vascular Studies
Indications for peripheral venous vascular examinations are separated into three major categories: deep vein thrombosis (DVT), chronic venous insufficiency, and vein mapping. Studies, which are medically necessary to determine subsequent treatment, are covered if the patient is a candidate for anticoagulation, thrombolysis or invasive therapeutic procedures.

A.    Deep Vein Thrombosis (DVT)
Indications: 
The signs and symptoms of DVT are relatively non-specific; and due to the risk associated with pulmonary embolism (PE), objective testing is allowed in patients who are candidates for anticoagulation or invasive therapeutic procedures for the following conditions:

1. Clinical signs and/or symptoms of DVT including edema, tenderness, inflammation, and/or erythema.
2. Clinical signs and/or symptoms of pulmonary embolism (PE) including hemoptysis, chest pain, and/or dyspnea.
3. Unexplained lower extremity edema status, post major surgical procedures, trauma, other or progressive illness/condition; surveillance following high-risk surgical       procedures, such as orthopedic or pelvic. Individual consideration will be given to surveillance of patients on prolonged bed rest (e.g., due to neurologic, condition / procedures, congestive heart failure, and paradoxical emboli). In general, surveillance is not necessary when effective antithrombotic measures (e.g., anticoagulants, alternating pressure devices) are being used.  However, it may be necessary in some patients prior to applying alternating pressure devices or compression dressings under appropriate clinical circumstances.
4. Unexplained lower extremity pain, excluding pain of skeletal origin.
5. Bilateral limb edema is rarely an indicator for medical necessity in the presence of signs and symptoms of heart failure, exogenous obesity, and/or arthritis.

B. Chronic Venous Insufficiency
Indications:
Chronic venous insufficiency may be divided into three categories: primary varicose veins, post-thrombotic (post-phlebitic) syndrome, and recurrent deep vein thrombosis. Peripheral vascular studies may be indicated in patients with:

1. Ulceration suspected to be secondary to venous insufficiency. These tests may be indicated to confirm this diagnosis by documenting venous valvular incompetence prior to invasive therapeutic treatment.
2. Varicose veins by themselves do not indicate medical necessity, but medical necessity may be indicated when they are accompanied by significant pain or stasis dermatitis. It is not medically necessary to study asymptomatic primary varicose veins (See WPS policy L34536, Treatment of Varicose Veins of the Lower Extremities).
3. Superficial thrombophlebitis involving the proximal thigh, to investigate whether there was thrombus at the saphenofemoral junction that would demand either anticoagulation or surgical ligation.
4. Evaluation is medically necessary in patients with symptoms of recurrent DVT or in patients prior to compression therapy to exclude superimposed acute DVT which may be at risk for embolization with such therapy.

C. Venous Mapping
Indications:
Vein mapping is considered medically reasonable and necessary when the patient’s clinical evaluation indicates one of the following:

1. Previous partial harvest of the vein.
2. Previous thrombophlebitis or DVT in the leg.
3. Severe varicose veins.
4. Previous history of vein stripping, ligation, or sclerotherapy.
5. Obesity to the degree it interferes with clinical determination.
6. Other indications must be clearly supported by medical documentation.
7. Vein mapping may be performed prior to creating a dialysis fistula. See section III in this policy on vessel mapping of vessels for hemodialysis.
8. Mapping the saphenous veins prior to scheduled revascularization procedures is covered when it is expected that an autologous vein will be used, but only if there is uncertainty regarding the availability of a suitable vein for bypass

Limitations:

1. Vein mapping as a routine preoperative study is not covered.
2. Duplex scan of extremity veins including responses to compression and other maneuvers; unilateral or limited study is indicated for the preoperative examination of potential harvest vein grafts to be utilized during bypass surgery. This is a covered service only when the results of the study are necessary to locate suitable graft vessels. The need for the bypass surgery must be determined prior to the performance of the test.

II. Hemodialysis Access Studies
Medicare considers a Doppler flow study medically necessary when the patient’s dialysis access site manifests signs or symptoms associated with vascular compromise, and when the results of this test are necessary to determine the clinical course of treatment. For examples supporting the medical necessity for Doppler flow studies see: CMS Pub 100-02 Medicare Benefit Policy Manual, Chapter 11-End Stage Renal Disease (ESRD), Section 40, H.

III. Vessel Mapping of Vessels for Hemodialysis Access
Indications:
Vessel mapping of vessels for hemodialysis access is considered for Medicare payment when it is performed preoperatively prior to creation of hemodialysis access using an autogenous hemodialysis conduit, including arterial inflow and venous outflow in patients with end stage renal disease (ESRD).  This is a covered service only when the results of the study are necessary to determine appropriate vessel utilization.  The need for a hemodialysis access site must be determined prior to the performance of the test. For limitations see: CMS Pub 100-02 Medicare Benefit Policy Manual, Chapter 11-End Stage Renal Disease (ESRD), Section 40, H. 

Credentialing and Accreditation Standards
The accuracy of non-invasive vascular diagnostic studies depends on the knowledge, skill, and experience of the technologist and interpreter. Consequently, the physician performing and/or interpreting the study must be capable of demonstrating documented training and experience. A vascular diagnostic study may be personally performed by a physician, a certified technologist, or in a certified vascular testing lab.

Services will be considered medically reasonable and necessary only if performed by appropriately trained providers.

1. All non-invasive vascular diagnostic studies must be performed meeting at least one of the following:
   1. performed by a licensed qualified physician, or
   2. performed by a technician who is certified in vascular technology, or
   3. performed in facilities with laboratories accredited in vascular technology.
2. A licensed qualified physician for these services is defined as:
   1. Having trained and acquired expertise within the framework of an accredited residency or fellowship program in the applicable specialty/subspecialty in ultrasound (US) or must reflect equivalent education, training, and expertise endorsed by an academic institution in ultrasound or by applicable specialty/subspecialty society in ultrasound, or
   2. Has the Registered Vascular Technologist (RVT), Registered Physician Vascular Interpretation (RPVI), or ASN: Neuroimaging Subspecialty Certification; and
   3. Is able to provide evidence of proficiency in the performance and interpretation of each type of diagnostic procedure performed.
3. Nonphysician personnel performing tests must demonstrate basic qualifications to perform tests and have training and proficiency as evidenced by licensure or certification by an appropriate State health or education department.  In the absence of a State licensing board, non-physician personnel must be certified by an appropriate national credentialing body. Appropriate personnel certification includes the American Registry of Diagnostic Medical Sonographers (ARDMS), Registered Vascular Technologist (RVT) credential; or Cardiovascular Credentialing International’s Registered Vascular Specialist (RVS).
4. Laboratories must be certified by one of the following:
   • Intersocietal Accreditation Commission (IAC),
   • American College of Radiology (ACR),
   • Joint Commission (Vascular lab certification would need to be noted under the main certification either under inpatient or ambulatory care depending on where the test is being performed), or
   • DNV-GL (specific for hospitals only)

   According to which certifying body listed above is selected, that accrediting body’s standards must be followed.