Virchow’s Triad
Virchow’s triad is a series of 3 changes that occur inside the veins, and that determine the formation of venous thrombi. The situation is also known as venous thromoboembolism .
This triad was described by a German pathologist named Rudolf Virchow, more than 150 years ago. He described, for the first time, the conditions necessary for venous thrombi to form and spread.
We will begin by describing the Virchow triad, and then several definitions that will allow us to understand venous thrombosis and its health risks.
What does Virchow’s triad comprise?
Virchow’s triad includes three changes:
- Blood flow abnormalities.
- Hypercoagulability: state that favors the formation of venous clots or thrombi.
- Endothelial damage: they are injuries to the interior of the blood vessels.
There are situations known as prothrombotic states that favor the appearance of the triad. Once the factors are attached, platelets accumulate as traps that retain neutrophils. Platelets, together with neutrophils, will form venous thrombi and lead to the disease thromboembolism.
Prothrombotic states: what are they?
Prothrombotic states are situations, hereditary or acquired, in which Virchow’s triad has a good chance of appearing. They are made up of modifiable and non-modifiable risk factors.
Genetic mutations, for example, when they involve clotting factors, can lead to a prothrombotic state. This inheritance is difficult or impossible to modify, since the risk factor is acquired at the moment of conception.
On the other hand, there are systemic diseases that stimulate blood clotting, such as cancer, high blood pressure, kidney disease, and chronic venous disease. People with varicose veins and venous insufficiency are particularly susceptible.
Habits and lifestyle are not minor in the thrombus equation. Obese people and those who smoke are at high risk. Those who must travel for long periods by plane, immobile, can stimulate clotting in their legs.
For women, special attention deserves the use of estrogens in hormonal contraceptives. A doctor should always assess the risk of thrombosis, before indicating contraception of this type. And during pregnancy, the pressure of the uterus on the veins that go to the lower limbs, slows down circulation, also favoring Virchow’s triad.
Other associated situations are:
- Chronic obstructive lung disease.
- Air pollution.
- Trauma to the lower limbs.
- Prolonged immobilization for hospitalizations longer than 48 hours.