Lymphology Association of North America (LANA) Practice Exam

How does a deep venous thrombosis (DVT) affect microcirculation distal to the affected area?

1. Filtration is increased because of decreased blood capillary pressure

2. A DVT doesn't influence microcirculation

3. Filtration is decreased because of increased blood capillary pressure

4. Filtration is increased because of increased blood capillary pressure

The correct answer is: Filtration is decreased because of increased blood capillary pressure

When considering the effects of a deep venous thrombosis (DVT) on microcirculation distal to the affected area, it's important to understand the role of blood capillary pressure and its impact on filtration processes. In the case of a DVT, blood flow is obstructed in the affected vein. This obstruction can lead to increased blood pressure in the capillaries upstream from the clot. When blood capillary pressure is elevated, it causes a rise in the hydrostatic pressure within those capillaries. This situation generally promotes an increased tendency for fluid to be filtered out of the capillaries into the surrounding interstitial space, which could lead to edema. However, at the distal site of the DVT, the increased hydrostatic pressure can also result in decreased effective perfusion of the capillaries located after the obstruction. The overall consequence of this can present as decreased net filtration due to the fact that if the capillary pressure is influenced substantially by the blockage, it could lead to less effective circulation and poor fluid exchange distal to the DVT. Additionally, as the pressure becomes elevated, the lymphatic system could also struggle to manage the excess interstitial fluid. Therefore, understanding that increased capillary pressure leads to a decrease in effective filtration