Venous thromboembolic events

Nature and mechanisms of embolism

The term embolism comes from the Greek word emballein, which literally means "to throw in". From the perspective of pathophysiology, it is the circulation within the blood or lymphatic vessels of particles that are not normally found there. These foreign particles are called emboli. Upon reaching vessels of smaller caliber, they cause mechanical blockage (occlusion) of them.

The pathological process in embolism is virtually always acute in nature. This is due to the fact that sudden vascular occlusion instantly deprives tissues of the ability to engage collateral blood flow compensation. As a result of such a sharp perfusion impairment, rapid and severe ischemia of the affected area develops.

Concept of VTE and the role of PE

The most threatening and frequent variant of embolism is pulmonary embolism (PE). This is an extremely life-threatening condition, the severity of which is directly determined by the scale of hemodynamic disorders arising from the obstruction of the pulmonary artery bed.

PE is closely related to another pathology — deep vein thrombosis (DVT). Together (and sometimes superficial venous thrombosis of the lower extremities is also included in this group), they form the umbrella term — venous thromboembolic events (VTE). The combination of these nosologies into a single category is no coincidence: they share identical risk factors and require a unified approach to pathogenetic therapy.

Risk assessment in nephrotic syndrome

Patients with nephrotic syndrome and focal segmental glomerulosclerosis (FSGS) must undergo mandatory VTE risk assessment. This is necessary to determine the precise scope of medical care and timely correction of therapy aimed at the prevention of venous thrombosis and embolism.

Statistical data demonstrate the high significance of the problem:

• The prevalence of thromboembolic complications in classic nephrotic syndrome averages 8% (95% confidence interval ranges from 4% to 15%).
• If a patient is diagnosed with FSGS, the average incidence of complications increases to 10%.
• The risk of thrombosis increases significantly in the event of a nephrotic syndrome relapse.

Laboratory diagnostics (Coagulogram)

To monitor the hemostatic system and assess VTE risks, a specific range of laboratory tests is used — an extended coagulogram. It necessarily includes the following parameters:

1. D-dimer concentration is recognized as the most reliable and clinically significant predictor of complications.
2. Prothrombin time.
3. INR (international normalized ratio).
4. aPTT (activated partial thromboplastin time).
5. Fibrinogen level.

A comprehensive analysis of these indicators allows the physician to detect hypercoagulation in a timely manner and prevent life-threatening consequences.

Class and exam questions

What else to study on this topic

• Pathogenetic therapy of VTE: unified approaches
• Mechanisms of hemodynamic disorders in pulmonary bed obstruction (PE)
• Effect of nephrotic syndrome relapses on the hemostatic system
• Superficial vein thrombosis of the lower extremities in the structure of VTE
• The role of fibrinogen and aPTT in the process of thrombus formation

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.