Tromboemboli

Tromboemboli are emboli that originate from thrombi and dislodge into the bloodstream, traveling to distant sites where they can obstruct blood vessels. The term typically encompasses venous thromboembolism, which includes deep vein thrombosis and pulmonary embolism, as well as arterial embolism that can cause organ or limb ischemia.

Pathophysiology and sources of risk are often explained by Virchow's triad: venous stasis, endothelial injury, and hypercoagulability. Most thromboemboli arise from the venous system, with deep vein thrombosis in the legs the common source; when a fragment travels to the lungs it causes pulmonary embolism. Arterial thromboemboli usually originate from the left heart or from proximal arteries and can cause cerebral, renal, splenic, or limb infarction.

Clinical features depend on location. Pulmonary embolism may present with sudden shortness of breath, chest pain, tachycardia, and sometimes hemoptysis. Arterial embolism can cause acute limb or organ ischemia, abdominal pain, or stroke symptoms such as sudden weakness or aphasia. Some thromboembolic events are silent or present with nonspecific symptoms.

Diagnosis relies on a combination of clinical assessment and tests. D-dimer testing may be used for risk stratification in low-suspicion cases. Imaging options include computed tomography pulmonary angiography for pulmonary embolism, ultrasound for deep vein thrombosis, echocardiography if heart sources are suspected, and vascular imaging for arterial emboli.

Treatment centers on anticoagulation, which is typically started promptly. Anticoagulants include heparin in the acute phase followed by warfarin or direct oral anticoagulants for a planned duration. In massive pulmonary embolism or life-threatening arterial embolism, thrombolysis or mechanical thrombectomy may be indicated. Prevention focuses on risk factor modification, early mobilization after surgery, and in high-risk patients, prophylactic anticoagulation. Complications can include recurrent events and chronic thromboembolic pulmonary hypertension.