Visualization of Coronary Artery Bypass Grafts and Coronary Artery Stents in Re-Animated and Perfusion Fixed Human Hearts

Abstract

Using Visible Heart® methodologies we imaged coronary artery bypass grafts (CABGs) and coronary stents in isolated beating human hearts and perfusion fixed human hearts. Due to the varying cardiac health of the donor hearts it has been possible to see progressive levels of stent endothelialization and vascular calcification. The isolated heart model uses a clear Krebs–Henseleit buffer in place of blood, allowing for the unique opportunity to image the coronary vessels. In the isolated human heart a fiberscope was inserted into either the native coronary artery or the CABG with the heart in sinus rhythm. In order to verify cardiac function during the imaging process the following measurements were read at a sampling rate of 5 kHz: ECG, aortic flow, and ventricular pressures. Perfusion fixed hearts were fixed in an end diastolic state achieved by applying pressures comparable to physiological conditions. This process causes the coronary arteries to fix in a dilated state. CABGs of human hearts were then imaged using fluoroscopy (angiograms) and fiberscopic techniques. The stented native coronary arteries of human hearts were imaged via fluoroscopy and by dissection. Through a variety of imaging techniques and using Visible Heart® methodologies we have obtained a unique visualization of a CABG and a coronary artery stent in a beating human heart during sinus rhythm. Investigative studies in perfusion fixed human hearts have provided a more complete anatomical imaging study of stent endothelialization in the native coronary arteries and vascular calcification in bypass grafts.