What does maximal hyperemia achieve during FFR assessment?

What does maximal hyperemia achieve during FFR assessment?

• A. Lowers heart rate and reduces blood pressure.
• B. Increases systemic vascular resistance.
• C. Reduces coronary perfusion pressure.
• D. Maximizes coronary blood flow to reveal the pressure drop across a stenosis.

Answer: (D)

Maximal hyperemia is used to open up the microvasculature as much as possible, lowering resistance so that blood flow is limited mainly by the stenosis itself. In this state, the coronary flow increases dramatically, and any pressure drop across a narrowing becomes much more pronounced. Measuring the distal coronary pressure (Pd) relative to the aortic pressure (Pa) under these conditions lets the operator quantify how much the lesion actually impedes blood flow. A functionally significant stenosis will show a larger drop in Pd, yielding a lower Pd/Pa ratio (the FFR value), which helps decide whether revascularization is needed. Agents like adenosine are used to achieve this maximal vasodilation. Other options aren’t the primary goal: the point of hyperemia isn’t to lower heart rate or raise systemic vascular resistance, and it doesn’t aim to reduce perfusion pressure overall. Instead, it creates a state where flow is governed by the lesion, so the pressure gradient across it can be accurately assessed.

Maximal hyperemia is used to open up the microvasculature as much as possible, lowering resistance so that blood flow is limited mainly by the stenosis itself. In this state, the coronary flow increases dramatically, and any pressure drop across a narrowing becomes much more pronounced. Measuring the distal coronary pressure (Pd) relative to the aortic pressure (Pa) under these conditions lets the operator quantify how much the lesion actually impedes blood flow. A functionally significant stenosis will show a larger drop in Pd, yielding a lower Pd/Pa ratio (the FFR value), which helps decide whether revascularization is needed. Agents like adenosine are used to achieve this maximal vasodilation.

Other options aren’t the primary goal: the point of hyperemia isn’t to lower heart rate or raise systemic vascular resistance, and it doesn’t aim to reduce perfusion pressure overall. Instead, it creates a state where flow is governed by the lesion, so the pressure gradient across it can be accurately assessed.