March 16, 2009

Coding for Deep Vein Thrombosis
For The Record
Vol. 21 No.6  P. 27

Deep vein thrombosis (DVT) is a condition in which a blood clot develops in a deep vein, typically located in the legs and thighs. If a blood clot develops in a deep vein, it may be serious because it can break loose and travel to the lungs (pulmonary embolism [PE]). 
Also documented as venous thrombosis and venous thromboembolism, DVT is classified to the following ICD-9-CM codes:

• 453.40, Venous embolism and thrombosis of unspecified deep vessels of lower extremity (This includes DVT and DVT not otherwise specified [NOS].);
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• 453.41, Venous embolism and thrombosis of deep vessels of proximal lower extremity (This includes femoral, iliac, popliteal, thigh, and upper leg NOS.);

• 453.42, Venous embolism and thrombosis of deep vessels of distal lower extremity (This includes calf, lower leg NOS, peroneal, and tibia.);

• 453.8, Other venous embolism and thrombosis of other specified veins (eg, upper extremity vein);

• 453.0, Hepatic vein thrombosis;

• 453.2, Venous thrombosis of vena cava; and

• 453.3, Venous thrombosis of renal vein.

If DVT is documented as a postoperative complication or iatrogenic, first assign code 997.2, Peripheral vascular complication, not elsewhere classified, followed by the code for the specific DVT site. If PE is also present with DVT, one of the following codes may also be assigned with the code for DVT:

• 415.11, Iatrogenic pulmonary embolism and infarction;

• 415.12, Septic pulmonary embolism (first code the underlying infection); and

• 415.19, Other pulmonary embolism and infarction.

DVT and PE sequencing will depend on the circumstances of admission.

In approximately one half of DVT cases, no symptoms are present. When they do occur, patients may experience swelling, pain, redness or discoloration, and warmth around the affected area.

The above symptoms are more routinely associated with thrombophlebitis, or the inflammation of the vein with a blood clot. When thrombophlebitis occurs, the body’s response to the inflammation may promote the formation of more clots. Occasionally, the physician may use the terms “DVT” and “thrombophlebitis” synonymously. According to coding directives, if both thrombophlebitis and DVT are documented, only a code for the thrombophlebitis is assigned (category 451). “If the physician lists only DVT as a diagnosis but the medical record documentation describes those conditions associated with thrombophlebitis, the physician should be queried” (AHA Coding Clinic for ICD-9-CM, 1992, first quarter, pages 15-16).

The first signs of DVT may be those associated with PE, including chest pain or discomfort, pain with deep breathing or coughing, unexplained and sudden shortness of breath, lightheadedness or dizziness, fainting, coughing up blood, a sense of anxiety or nervousness, rapid breathing, or a fast heart rate. To diagnose deep vein thrombosis, the physician may do the following:

• a complete medical history (Patients with a history of DVT are at a greater risk of developing it again.);

• a physical exam to evaluate signs;

• an ultrasound to create a picture of blood flowing through veins and to possibly visualize a clot;

• a CT or MRI test;

• a D-dimer test (D-dimer is a substance in the blood that is released when a blood clot dissolves. An elevated D-dimer may indicate DVT.);

• a venography, during which dye is injected into a vein and an x-ray is taken to create images to look for clots; or

• a ventilation perfusion scan, which is performed if the physician thinks PE is present. This diagnostic study uses a radioactive material to show how well oxygen and blood are flowing to the lungs.

Anticoagulants are one of the main medications used to treat DVT, decreasing the blood’s ability to clot. They do not break up existing clots but do prevent clots from getting bigger, reducing the risk of developing additional ones. The patient may start with heparin injections followed by warfarin orally. The patient may take anticoagulants for three to six months. If he or she is receiving anticoagulants long-term, assign code V58.61 as a secondary diagnosis. It would not be appropriate to assign a code for the DVT because it’s no longer present, as the patient is on the anticoagulants to prevent additional blood clots (AHA Coding Clinic for ICD-9-CM, 2002, first quarter, pages 15-16).

Vena cava filters (38.7) are inserted to prevent clots that break loose from lodging in the lungs. These filters, also called umbrellas, do not stop new blood clots from developing.
Coding and sequencing for DVT are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to more than 4,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.