Perfusion balloon prolonged inflation in lipid-rich coronary lesions and slow flow/no-reflow: NIRS-IVUS insights

Background Lipid-rich plaques can cause distal embolization and slow flow/no-reflow (SFNR) during percutaneous coronary intervention (PCI), leading to adverse clinical outcomes. Perfusion balloons (PB), enabling prolonged dilatation while maintaining distal perfusion, have been reported to reduce distal embolization and SFNR. However, their mechanistic impact on lipid-rich plaques remains incompletely understood. Purpose This study aimed to evaluate the impact of PB on lipid core plaques in high-risk lesions using near-infrared spectroscopy–intravascular ultrasound (NIRS-IVUS), assessing changes in maxLCBI4mm, lipid core plaque area, and intraprocedural SFNR. Methods This single-center retrospective study was conducted on consecutive patients who underwent NIRS-IVUS-guided PCI between January 2025 and January 2026. Lesions with a pre-procedural maxLCBI4mm ≥400 were analyzed. We excluded patients with stentless procedures or poor image quality. Patients were categorized into the PB group and the conventional balloon (CB) group based on the balloon type used prior to stent implantation. Transient SFNR was defined as a TIMI flow grade ≤2 occurring during the procedure, followed by recovery to TIMI 3 flow by the end of PCI after adjunctive treatments, including intracoronary vasodilators, whereas final SFNR was defined as a TIMI flow grade ≤2 on the final angiogram. Plaque burden was assessed by IVUS, and lipid core plaque area was quantified pre- and post-procedure at the same location using ImageJ software from longitudinal frames derived from NIRS chemograms. Serial NIRS-IVUS measurements were obtained at matched segments before balloon dilatation, after dilatation, and after stenting using anatomical landmarks and constant-speed pullback. Results Of the 44 patients undergoing NIRS-IVUS-guided PCI during the study period, 29 cases were included in the analysis (PB, n=16; CB, n=13). Balloon length (PB: 20.0 mm vs. CB: 10.0 mm, p<0.001) and inflation time (PB: 180 s vs. CB: 20 s, p<0.001) differed between groups, whereas other baseline characteristics were comparable. Transient SFNR occurred in 1 patient (6.3%) in the PB group and 5 patients (38.5%) in the CB group (p=0.064). No statistically significant differences were observed in reductions of maxLCBI4mm or lipid core plaque area. However, the PB group showed a tendency toward a smaller reduction in lipid core plaque area after balloon dilatation (PB: −7.4% vs. CB: −35.2%, p=0.159). Conclusion(s) Prolonged dilatation using a PB may potentially reduce distal embolization by preventing rapid dispersion of lipid-rich plaque components during PCI. Although no statistically significant difference was observed in this small cohort, the PB demonstrated a tendency toward reduced SFNR incidence and decreased lipid-rich plaque disruption, suggesting a potential mechanism for microvascular protection.