thrombosis

DEFINITION of thrombosis

Thrombosis is the pathological process by which a thrombus — a solid mass of coagulated blood — forms within an intact blood vessel (artery, vein, or cardiac chamber) and remains at the site of formation, partially or completely obstructing circulation. It is driven by Virchow’s Triad: (1) endothelial injury (damage to the vessel wall), (2) venous stasis or turbulent flow (sluggish or disrupted blood movement), and (3) hypercoagulability (an elevated tendency of blood to clot). The clinical consequences depend on the type and location: venous thrombosis (most commonly deep vein thrombosis/DVT of the lower extremities) risks pulmonary embolism (PE) if the clot dislodges; arterial thrombosis (coronary, cerebral, or peripheral) causes ischemia or infarction of the downstream tissue. Treatment depends on acuity and location: anticoagulation (heparin, warfarin, DOACs), catheter-directed thrombolysis, mechanical thrombectomy, or surgical embolectomy.

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ETYMOLOGY of thrombosis

greek From Greek thrombōsis, from thrombos (θρόμβος) = “clot, lump, curd” + the suffix -sis (denoting a process or condition). The root thrombos likely derives from a Proto-Indo-European root meaning “to press together” or “to thicken.” The term was first recorded in English in the mid-19th century (c. 1706 per Merriam-Webster, in regular medical use by 1800s). The combining form thrombo- (as in thrombolysis, thrombocyte, thromboembolism) is derived from the same Greek root.

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ALIASES / POSSIBLE FORMS of thrombosis

Term	Meaning
Thrombus	The actual blood clot (noun); plural: thrombi
DVT	Deep vein thrombosis
Thromboembolism	Thrombus that has detached and traveled (embolized)
Phlebothrombosis	Thrombosis within a vein (older/synonym)
Thrombophlebitis	Vein thrombosis with associated inflammation
Arterial thrombosis	Clot within an artery (MI, stroke, peripheral ischemia)
Thrombophilia	Hereditary or acquired hypercoagulable state
Thrombocytopenia	Low platelet count, often related to clotting risk
Thrombolysis	Dissolution of a thrombus (pharmacological or mechanical)
Thrombectomy	Surgical or mechanical removal of a thrombus
VTE	Venous thromboembolism (DVT + PE together)

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✅CODING CORNER

ICD-10-CM

Deep Vein Thrombosis — Lower Extremity (Acute, Category I82.4-)

ICD-10	Description
I82.401	Acute DVT, unspecified deep veins, right lower extremity
I82.402	Acute DVT, unspecified deep veins, left lower extremity
I82.403	Acute DVT, unspecified deep veins, bilateral lower extremity
I82.409	Acute DVT, unspecified deep veins, unspecified lower extremity
I82.411	Acute DVT of right femoral vein
I82.412	Acute DVT of left femoral vein
I82.421	Acute DVT of right iliac vein
I82.422	Acute DVT of left iliac vein
I82.431	Acute DVT of right popliteal vein
I82.432	Acute DVT of left popliteal vein
I82.441	Acute DVT of right tibial vein
I82.442	Acute DVT of left tibial vein

DVT — Lower Extremity (Chronic)

ICD-10	Description
I82.501	Chronic DVT, unspecified deep veins, right lower extremity
I82.502	Chronic DVT, unspecified deep veins, left lower extremity
I82.503	Chronic DVT, unspecified deep veins, bilateral lower extremity

DVT — Upper Extremity

ICD-10	Description
I82.621	Acute DVT of deep veins, right upper extremity
I82.622	Acute DVT of deep veins, left upper extremity
I82.629	Acute DVT of deep veins, unspecified upper extremity

Pulmonary Embolism (PE)

ICD-10	Description
I26.09	Other pulmonary embolism with acute cor pulmonale
I26.99	Other pulmonary embolism without acute cor pulmonale
I26.93	Single subsegmental thrombotic pulmonary embolism
I26.94	Multiple subsegmental thrombotic pulmonary embolism

Coronary / Cerebral / Other Arterial Thrombosis

ICD-10	Description
I21.9	Acute MI, unspecified (often thrombotic in origin)
I63.00	Cerebral infarction due to thrombosis of unspecified precerebral artery
I74.3	Embolism and thrombosis of arteries of lower extremities
I74.4	Embolism and thrombosis of arteries of upper extremities
I82.91	Chronic embolism and thrombosis of unspecified vein

Anticoagulation Status (Code additionally when applicable)

ICD-10	Description
Z79.01	Long-term (current) use of anticoagulants
Z79.02	Long-term (current) use of antithrombotics/antiplatelets

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CPT (Thrombosis Procedures)

Mechanical Thrombectomy

CPT	Description
37184	Primary percutaneous transluminal mechanical thrombectomy, arterial or bypass graft; initial vessel
+37185	Primary arterial mechanical thrombectomy; second and all subsequent vessels, same vascular family (add-on)
+37186	Secondary percutaneous transluminal thrombectomy, arterial or bypass graft (add-on)
37187	Percutaneous transluminal mechanical thrombectomy, vein(s); including intraprocedural thrombolytic injections and fluoroscopic guidance
37188	Same as 37187 — repeat treatment on subsequent day during course of thrombolytic therapy

Catheter-Directed Thrombolysis (CDT)

CPT	Description
37211	CDT thrombolysis, arterial — initial treatment day
37212	CDT thrombolysis, venous — initial treatment day
37213	CDT thrombolysis, arterial or venous — subsequent treatment day (any middle day)
37214	CDT thrombolysis, arterial or venous — last treatment day (includes catheter removal and access closure)

IVC Filter

CPT	Description
37191	Insertion of intravascular vena cava filter, percutaneous
37192	Repositioning of intravascular vena cava filter, percutaneous
37193	Retrieval of intravascular vena cava filter, percutaneous

Key Coding Tips

• Codes 37211-37214 do NOT include catheter placement, diagnostic angiography, or other interventions — report those separately when documented.
• 37187 includes intraprocedural thrombolytic infusions and fluoroscopic guidance; do not additionally report thrombolysis codes for injections given during mechanical thrombectomy.
• If thrombolysis begins and ends on the same calendar day, report only the initial treatment day code (37211 or 37212).
• For intracranial arterial thrombolysis, do not use 37211 — use 61645 instead.
• Always code long-term anticoagulant use (Z79.01) as an additional diagnosis when applicable.
• Common modifiers: -59 (distinct procedural service); -76 (repeat procedure, same physician); -78 (unplanned return to OR, related, during global period); -79 (unrelated procedure during global period); -LT/-RT for laterality on vascular procedures where applicable.

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DERIVATIONS of thrombosis

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Med roots dictionary Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms