Saline vs Contrast for Optical Coherence Tomography During Percutaneous Coronary Intervention

BACKGROUND: OCT improves PCI outcomes compared with angiography alone but requires contrast to displace blood for image acquisition. In patients at risk of contrast-induced nephropathy, minimizing contrast use is clinically important. OBJECTIVES: The objective of the study was to compare heparinized saline and contrast as flushing media for coronary frequency domain optical coherence tomography (OCT) during percutaneous coronary intervention (PCI). METHODS: In this prospective, multicenter, observational study, paired contrast and heparinized saline OCT pullbacks were obtained during the same procedure from 166 patients undergoing PCI at 4 tertiary centers in India. A total of 2072 matched pairs of OCT frames (in 259 paired OCT runs) were analyzed by 2 blinded investigators. Vessel dimensions including proximal reference diameter, minimal lumen area, minimum lumen diameter, and distal reference diameter (DRD) were compared. Ethical approval was obtained at all participating institutions, and all patients provided informed consent. RESULTS: ; P = 0.85), minimum lumen diameter (2.55 ± 0.68 vs 2.56 ± 0.66 mm; P = 0.78), or distal reference diameter (2.54 ± 0.55 vs 2.55 ± 0.55 mm; P = 0.83). Bland-Altman analysis showed good agreement without proportional bias. Interobserver reliability for vessel measurements was moderate to good with Intraclass Correlation Coefficient ranging from 0.69 to 0.79. Sensitivity analysis for clustering confirmed the robustness without proportional bias. No adverse events were observed with saline flushes. CONCLUSIONS: Heparinized saline provides vessel measurements comparable to contrast media for frequency domain OCT without safety concerns. Saline flushing is a feasible alternative for OCT-guided PCI, particularly in patients at risk of contrast-induced nephropathy.