A novel quantitative method for evaluating diffuse in-stent narrowing at follow-up angiography.

Area of Science:

• Cardiovascular research
• Medical imaging analysis
• Interventional cardiology

Background:

• In-stent restenosis (ISR) presents challenges in objective characterization.
• Distinguishing diffuse from focal ISR is crucial for treatment planning.

Purpose of the Study:

• To introduce and validate a new quantitative parameter, the diffuse index (DI).
• To assess the correlation of DI with percentage plaque area (% PA).
• To evaluate the predictive value of DI and % PA for major adverse cardiac events (MACE).

Main Methods:

• Quantitative coronary angiography (QCA-CMS) was used to analyze 346 lesions in 343 patients.
• The diffuse index (DI) was calculated as the ratio of lesion length at a specific reference diameter function (RDF) to total stent length (DI = [LL(x)/SL]).
• Correlation between DI and % PA was assessed, and the incidence of MACE was analyzed based on DI and % PA thresholds.

Main Results:

• An excellent correlation (r > 0.88) was observed between DI at 88% RDF and % PA across different stent types.
• The correlation curves were consistent regardless of the stent used.
• A combination of DI > 0.8 and % PA > 30% was associated with a high incidence of MACE (52%).

Conclusions:

• The diffuse index (DI) is a novel, objective quantitative parameter for characterizing ISR as diffuse or focal.
• DI shows a strong correlation with % PA, offering a consistent measure across various stents.
• DI combined with % PA can identify patients at high risk for MACE.