Anything that restricts the flow of blood into the left side of the heart will cause an increase in the pulmonary blood pressure. Mitral valve narrowing (stenosis) was a very common factor in the years when rheumatic heart disease was more prevalent. One of the more important factors today is lung disease that results in the loss of pulmonary vasculature. Emphysema is just such a condition. With the loss of pulmonary alveolar tissue, we also see the loss of the associated vasculature. This results in fewer channels for the blood to flow through, and as the resistance rises, so does the pulmonary blood pressure. As you can guess, the whole cycle is one of a down hill spiral. These are two categories of disease that will lead to the condition seen in this slide, there are others. Now that you know what is happening, see if you can dream up a few more.
 

Mark Braun, MD braunm@indiana.edu
Copyright 1998, the Trustees of Indiana University