Which criterion indicates hemodynamically significant left main or proximal LAD stenosis?

Which criterion indicates hemodynamically significant left main or proximal LAD stenosis?

• A. FFR ≤ 0.80.
• B. Angiographic stenosis > 50% without physiology.
• C. Exercise-induced chest pain.
• D. Normal LV function.

Answer: (A)

Determining whether a left main or proximal LAD stenosis is hemodynamically significant relies on physiology—the actual impact of the lesion on blood flow—rather than how narrow it looks on angiography. Fractional flow reserve measures the pressure gradient across the narrowing during maximal vasodilation; an FFR of 0.80 or less indicates that the lesion reduces distal perfusion enough to cause ischemia, meaning the patient would likely benefit from revascularization. This physiologic threshold is a stronger predictor of adverse outcomes and guides treatment decisions better than anatomy alone. Angiographic stenosis greater than 50% without physiology can be misleading because many lesions that look moderate may not cause ischemia, while some less-than-severe looking lesions can be functionally significant. Symptoms like exercise-induced chest pain describe experience but do not quantify the lesion’s impact on blood flow. Normal left ventricular function can still accompany a hemodynamically significant lesion, so LV function alone doesn’t rule out ischemia.

Determining whether a left main or proximal LAD stenosis is hemodynamically significant relies on physiology—the actual impact of the lesion on blood flow—rather than how narrow it looks on angiography. Fractional flow reserve measures the pressure gradient across the narrowing during maximal vasodilation; an FFR of 0.80 or less indicates that the lesion reduces distal perfusion enough to cause ischemia, meaning the patient would likely benefit from revascularization. This physiologic threshold is a stronger predictor of adverse outcomes and guides treatment decisions better than anatomy alone.

Angiographic stenosis greater than 50% without physiology can be misleading because many lesions that look moderate may not cause ischemia, while some less-than-severe looking lesions can be functionally significant. Symptoms like exercise-induced chest pain describe experience but do not quantify the lesion’s impact on blood flow. Normal left ventricular function can still accompany a hemodynamically significant lesion, so LV function alone doesn’t rule out ischemia.