Improving the cardiac cath-lab interventional imaging eco-system
Minimally invasive, transcatheter therapeutic interventions for structural heart disease have evolved over the past several decades as appealing alternatives to open-chest surgery. Smaller incisions, shorter hospital stays and quicker recovery are outcomes that are ubiquitous to all approved transcatheter procedures, in comparison to traditional surgery. X-ray fluoroscopy (XRF) is the most commonly used imaging modality to guide transcatheter procedures. XRF offers certain advantages. Interventionalists have close familiarity with XRF systems. These systems are also widely available in centers with cardiac catheterization laboratories. XRF can visualize high X-ray attenuating devices such as radio-opaque catheters and metallic stents. However, XRF has certain disadvantages. For example, soft tissues such as myocardium, and valves are visualized poorly. Chambers and vessels are only transiently visible when filled with boluses of iodinated contrast, which can be nephrotoxic in susceptible individuals. Conventional X-ray also images using the principle of “projection” imaging, making it difficult to judge three dimensional (3D) perspective. Finally, over-reliance on XRF as the sole imaging modality exposes the patient and in-room personnel to the harmful effects of ionizing radiation. Wholly magnetic resonance imaging (MRI) (1-4) and ultrasound guided (US) (5,6) cardiovascular interventions have been tested in animal models and clinical studies as ionizing radiation-free alternatives to XRF. However, wide adoption of these methods has been prevented in large part by the lack of visually conspicuous devices that still maintain high mechanical performance.