Undersizing in balloon angioplasty leads to which consequence?

• A. Part of the vessel remains smaller than the rest, increasing restenosis risk.
• B. Uniform dilation with low restenosis risk.
• C. Vessel overexpansion with dissection.
• D. Immediate occlusion of the vessel.

Answer: (A)

Undersizing a balloon during angioplasty means choosing a balloon diameter smaller than the vessel’s reference size, so the plaque isn’t adequately compressed and the lumen remains narrowed in part. That residual stenosis leaves a segment of the vessel with reduced diameter, which can provoke turbulent flow and stimulate neointimal hyperplasia, increasing the likelihood of restenosis over time. In contrast, appropriate sizing aims for uniform dilation with minimal residual narrowing; overexpansion or dissection is more likely with an oversized balloon or too aggressive inflation, and immediate occlusion suggests thrombosis or rupture rather than undersizing.