Deep venous thrombosis (DVT) and pulmonary embolism (PE) are intimately related conditions, the latter caused by the former in the vast majority of cases. Properly coding these conditions requires a working knowledge of some crucial diagnostic criteria and documentation requirements.
The term “DVT” is intended for venous thrombosis without accompanying phlebitis. The proper term for venous thrombosis with phlebitis is “thrombophlebitis.” This distinction is important for proper code assignment. PE is nearly always caused by DVT, deep vein thrombophlebitis, or central vein thrombosis.
Deep veins include those of the lower extremities (e.g., iliac, femoral, popliteal). ICD-10-CM provides separate codes for acute versus chronic DVT but makes no such distinction for thrombophlebitis. Unique codes are assigned for thrombosis of central veins (e.g., renal, portal, vena cava).
Acute DVT and PE are usually treated with heparin-type medications for immediate anticoagulation to prevent further clot growth, and then the patient is transitioned to warfarin or a direct oral anticoagulant for intermediate-term therapy to prevent recurrent DVT or PE. These medications do not “treat” the thrombus or embolus, which are usually dissolved spontaneously by endogenous thrombolytic processes within a few days.
The acute episode of DVT or PE ends in 14 days or less when the patient is stabilized, transitioned to a longer-term medication, and discharged. If such a patient is subsequently admitted without a recurrent episode of DVT or PE, the correct status is “history of” DVT/PE, not acute or chronic DVT/PE.
Chronic DVT or chronic PE is a situation in which either condition has acutely recurred one or more times. Chronic lifelong anticoagulation is usually recommended after the first recurrence, or after the initial episode for patients with certain underlying chronic clotting disorders.
When recurrent episodes of DVT become “chronic” is a subjective decision requiring physician determination. Factors to be considered are the number and frequency of episodes and the need for lifelong anticoagulant therapy. Inferior vena cava filters are often utilized for chronic DVT and/or PE.
Acute and chronic DVT are classified using codes from subcategories I82.4 and I82.5, respectively (see Table 1). Deep vein thrombophlebitis, regardless of acuity, is assigned one of the codes from category I80, almost all of which are in hierarchical condition category (HCC) 108. Acute PE is classified by category I26 combination codes with or without acute cor pulmonale, and chronic PE is assigned code I27.82 (see Table 2). “History of” DVT, thrombophlebitis, or PE is assigned to personal history codes Z86.718, Z86.72, and Z86.711, respectively.
As a secondary diagnosis, all codes for acute and chronic DVT are categorized as complications/comorbidities (CCs) and almost all of them are included in HCC 108 (vascular disease without complication). Almost all thrombophlebitis codes are also CCs and included in HCC 108. When PE is not the principal diagnosis, all acute PE codes are major CCs and in HCC 107 (vascular disease with complication); chronic PE is a CC and in HCC 107.
In summary, for correct coding, always make the distinction between DVT (without phlebitis) and thrombophlebitis. Remember and correctly document the distinctions among acute, chronic, and “history of” DVT or PE.