Deep Vein Thrombosis

Incidence in USA: 170,000–200,000 new cases; 90,000–100,000 recurrent cases.

VTE is the third most frequent acute cardiovascular syndrome after MI and CVA.

Half of all episodes are associated with recent surgery or hospitalization.

VTE is recognized as the leading cause of preventable death in hospitalized pts.

Modified Caprini risk model can be used to predict risk in general surgical pts.

Without prophylaxis, DVT develops in close to 30% of general surgical pts.

With chemical prophylaxis, risk can be reduced to 8% for general surgical pts.

Incidence of fatal PE: 0.1 (general surgery)–5% (total knee replacement).

Pulm embolism

• Cardiac arrest, electromechanical dissociation

• Increased A-a gradient, increased dead space, potentially leading to respiratory acidosis

Increased bleeding risk, safety of regional anesthesia in anticoagulated pts

Risks and benefits of discontinuing anticoagulation for surgery

Classic symptoms of DVT: swelling, pain, and erythema of the involved extremity.

GA associated with increase in tissue factor, vWF, tissue plasminogen activator, resulting in hypercoagulable/hypofibrinolytic state.

Dx.

• Contrast venography (gold standard); requires IV contrast exposure; 2–3% incidence of inducing thrombosis.

• Compression/duplex ultrasonography of femoral/popliteal veins has sens/spec of 97% in symptomatic pts (less sens for more distal [calf] veins).

• IP, also more sensitive in proximal (90%) than distal.

• D dimer has high negative predictive value useul to rule out VTE).

See also Pulmonary Embolism .