Intracoronary pressure increase due to contrast injection for optical coherence tomography imaging.

Background: Optical coherence tomography (OCT) requires intracoronary injection of contrast media to remove blood from the field of view during image acquisition. Contrast injection may cause a temporal increase in intracoronary pressure. The aim of this study was to compare the intracoronary pressure during contrast injection between OCT and coronary angiography.

Methods: We measured intracoronary pressure by using a pressure guidewire during contrast injection for OCT and angiography in 30 coronary arteries (mean fractional flow reserve = 0.90 ± 0.03). Contrast media was injected into coronary artery through the guiding catheter by using a mechanical injector pump.

Results: Intracoronary pressure before contrast injection was similar between OCT and angiography (systolic pressure: 123 ± 18 mmHg vs. 122 ± 19 mmHg, p = 0.863). Intracoronary pressure was increased due to contrast injection in both OCT (systolic pressure: 123 ± 18 mmHg to 132 ± 18 mmHg, p < 0.001) and angiography (systolic pressure: 122 ± 19 mmHg to 128 ± 19 mmHg, p < 0.001). The increase in intracoronary pressure was slightly greater in OCT compared with angiography (absolute increase of systolic pressure: 9 ± 2 mmHg vs. 6 ± 1 mmHg, p < 0.001; and relative increase of systolic pressure: 8 ± 2% vs. 5 ± 1%, p < 0.001). Intracoronary pressure during contrast injection was not significantly different between OCT and angiography (systolic pressure: 132 ± 18 mmHg vs. 128 ± 19 mmHg, p = 0.831).

Conclusions: Contrast injection for OCT induced significant but small increase in intracoronary pressure compared with that for angiography.