Which of the following is the first step in the progression of coronary heart disease?

The first step in the progression of coronary heart disease is characterized by an artery that is open with no fatty deposits or plaque. This stage represents a healthy cardiovascular system where the blood vessels are clear of any blockages or buildups, allowing for normal blood flow. It highlights the baseline condition of the arteries before any pathology begins to develop.

The subsequent steps in the progression involve the accumulation of fatty streaks and plaque, which develop over time as risk factors such as high cholesterol, hypertension, and lifestyle choices come into play. As these risk factors increase, the condition of the artery can deteriorate into stages that show early signs of disease, such as fatty streaks, and later stages, which involve more severe plaque development and narrowing of the artery walls. Starting with a healthy, open artery establishes a foundational understanding of cardiovascular health before delving into the complexities of coronary heart disease.