Impact of Stepwise Pressure-Increasing NC Balloon Post-Dilation on Stent Expansion (SPND)

Coronary atherosclerotic heart disease remains one of the leading causes of mortality and disability worldwide. Coronary stent implantation is a principal therapeutic strategy for coronary artery stenosis. The adequacy of stent expansion is a critical determinant of treatment efficacy; inadequate stent expansion may lead to stent malapposition, in-stent restenosis, stent thrombosis, and other adverse events that significantly compromise patient prognosis.

Intravascular ultrasound (IVUS), as an invasive vascular imaging modality, enables clear visualization of vessel wall architecture, plaque characteristics, and immediate post-stent implantation outcomes. Among its measurements, the external elastic membrane (EEM) cross-sectional area serves as a key reference for stent sizing, effectively overcoming the inherent limitation of conventional coronary angiography, which relies solely on luminal imaging for stent diameter selection.

Non-compliant (NC) balloon post-dilation is an essential step in optimizing stent implantation outcomes. Gradual incremental increases in balloon pressure may further promote adequate stent expansion and improve stent-vessel wall apposition. However, the specific impact of NC balloon post-dilation at different pressures and durations on stent expansion rate has not been systematically validated. To date, there remains a paucity of dedicated studies investigating the dynamic changes in stent expansion rate under a stepwise pressure-increasing protocol.

This study utilizes IVUS-EEM measurements to guide stent sizing and adopts a single-stent implantation strategy combined with multi-stage stepwise pressure-increasing NC balloon post-dilation. after stent deployment with norminal pressure, 12*10 atm, 18*10 atm and 24*10 atm NC balloon post-dilation. IVUS measurement will be made after each step and stent expansion and Minimal stent area will be documented.

Primary Endpoint. Minimum Stent Area (MSA)

IVUS-measured minimum lumen cross-sectional area within the stented segment post-procedure (after stent deployment with norminal pressure, 12*10 atm, 18*10 atm and 24*10 atm NC balloon post-dilation)

Secondary endpoints:

Stent Expansion Rate

IVUS-measured stent expansion rate immediately post-procedure (after stent deployment with norminal pressure, 12*10 atm, 18*10 atm and 24*10 atm NC balloon post-dilation), calculated as: (minimum stent cross-sectional area [MSA] measured by IVUS / manufacturer's nominal MSA) × 100%.

rates of stent edge dissection, hematoma, perforation.