Contrast-Enhanced Coronary Artery and Coronary Artery Bypass Graft Imaging Using Aortic Root Catheter Injection With Computed Tomographic Angiography (CTA)

Coronary artery disease remains the leading cause of death worldwide. The diagnosis via the gold standard, cardiac catheterization, remains a time consuming, expensive, and invasive procedure with some considerable risks. In addition, there is a significant risk due to cumulative amount of iodinated contrast delivered (between 80 - 120 cc) in patients who have abnormal renal insufficiency or at a high risk for developing contrast nephropathy. Cardiac catheterization specifically involves arterial puncture with a needle, usually in the groin or upper extremity, through which a guidewire is passed fluoroscopically to the ascending aorta. A catheter is then inserted over the guidewire and subsequently, the guidewire is removed and iodinated contrast is injected to opacify the aorta or coronary arteries. As such, there are different kinds of catheters that are used to engage either the right or left native coronary arteries or by-pass vein grafts. This procedure requires separate injections into the coronary arteries or by-pass grafts which can induce arrhythmias, require over one hour of procedural time, requires larger bore catheters, exposes the physician and patient to ionizing radiation and subjects the patient with coronary artery disease to contrast induced nephropathy, especially in cases requiring higher loads of iodinated contrast.

Of the noninvasive techniques, the most common limiting factor when employing IV-enhanced CTA is the underlying blood pool, which also enhances when contrast-enhanced protocols are employed using a peripheral intravenous contrast injection route. This results in a frequent obscuration of the native coronary arteries. Reproducible enhancement of the distal and tributary anatomy is another pitfall with IV-enhanced coronary CTA. In addition, the amount of contrast agent required is similar to that amount required during invasive coronary angiography. As such, the method of the present study provides an imaging concept of the coronary arteries employing a catheter device in conjunction with computed tomography (CT) imaging machine that will enable a reduction of the total amount of dye delivered to the patient.