9.3 UHD and 3D Coronary Imaging

These proceedings summarize the educational activity of the 16th Biennial Meeting of the International Andreas Gruentzig Society held January 31-February 3, 2022 in Punta Cana, Dominican Republic

Faculty Disclosures     Vendor Acknowledgments

2022 IAGS Summary Document

 Statement of the problem or issue

Digital angiography is the gold standard for imaging vascular structures in the cardiac catheterization laboratory. However, it has several features which limit its utility during complex coronary and microvascular interventions (Table 1). Image resolution with digital angiography is a critical factor in success of percutaneous vascular interventions, particularly those involving small-sized (<4 mm diameter) blood vessels and/or complex maneuvers. Current flat panel detectors (FPD) have a resolution of 154-200 µm. However, a new ultra–high-definition (UHD) imaging system can acquire images at a resolution of 76 µm.

Gaps in knowledge

Practical utility of UHD imaging has not been extensively demonstrated. To overcome this gap, we studied the utility of a new UHD imaging system during percutaneous cardiac and vascular procedures in our catheterization lab. We report 4 representative scenarios in which UHD imaging was able to overcome the limitations of standard FPD. In each case, the hi-def mode was activated at the operator’s discretion, and standard FPD images were used for qualitative comparison.

In the first case, UHD enabled us to diagnose stent fractures and avulsion in a patient with prior tibial stents that were not apparent by standard FPD imaging even at high magnification. The improved visibility with UHD allowed us to manipulate wires easily and then accurately position a new stent at the bifurcation of the tibioperoneal trunk. In our second example, UHD enabled us to deploy stents with a high degree of precision during a complex left main artery intervention. Extreme angulation and calcification at the origin of the branch vessels made it difficult to use intravascular ultrasound in this situation. Our third case highlighted the utility of UHD imaging in troubleshooting and successfully completing the removal of a partially deformed inferior vena cava filter after conventional imaging techniques failed. Our fourth case demonstrated the use of UHD in performing angioplasty of the digital arteries of the hand (diameter <1.5 mm) in a patient with critical ischemia secondary to refractory Raynaud’s phenomenon. Importantly, all 4 cases were successfully completed without significantly increasing radiation exposure to the patients.

Possible solutions and future directions

The success of complex coronary and peripheral vascular interventions depends upon the operators’ ability to accurately visualize vascular anatomy and precisely maneuver and deploy devices. Most commercially available FPD systems render images with a resolution of 154-200 µm. A new UHD system can render images with much higher resolution of 76 µm.  The safety and applicability of this technology has already been established for neurointerventional procedures.¹ We found that UHD imaging can likewise be useful in coronary and peripheral interventional procedures without increasing either procedure time or radiation exposure. UHD imaging allowed operators to resolve ambiguities in vascular anatomy, facilitate delivery of interventional equipment, and detect structural anomalies in malfunctioning devices. Furthermore, the availability of UHD enabled us to devise new procedures such as digital angioplasty to treat refractory hand ischemia in a patient with Raynaud’s phenomenon (Figure 1). Additional studies are needed to better define the role and optimal integration of UHD imaging into contemporary interventional practice.

Reference

1. Setlur Nagesh SV, Vakharia K, Waqas M, et al. High-definition zoom mode: a high resolution x-ray microscope for neurointerventional treatment procedures. J Neuroimaging. 2019;29(5):565-572. doi:10.1111/jon.12652