NOVEL ANGIOGRAPHIC TECHNIQUES FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE AND FOR ASSESSMENT OF ITS PERCUTANEOUS TREATMENT

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Coronary angiography is considered the standard for coronary anatomy definition. The utility of coronary angiography is dependent on its ability to identify the structure of the coronary vascular bed and the presence of obstructive disease. However, radiographic imaging of the coronary tree depicts the arteries as simple 2-dimensional projections of the lumen and this "luminogram" is a poor representation of the real coronary anatomy. The combination of foreshortening, tortuosity, overlap, and anatomic variation may result in insufficient description of the real coronary anatomy. Rotational and 3-dimensional techniques have been developed to minimize the imaging limitations of 2-dimensional angiography. Rotational angiography is a technique that provides, with one single contrast injection, a dynamic cine-angiogram of the coronary tree, during a rotation of the gantry around the thorax of the patient. This single rotational acquisition of the coronary tree, matched with the electrocardiographic recording of the patient, permits the automatic selection, of 2 different views of the coronary segment of interest in the same phase of the cardiac cycle. These views are used to reconstruct a 3-dimesnional model, which allows automatic “auto-calibrated” measurements of the coronary arteries. Rotational angiography and 3-dimensional modeling are compared with standard 2-dimensional techniques in the first part of this thesis. Rotational angiography provides similar image quality as conventional 2-dimensional angiography, while 3-dimensional modeling has the potential to provide more accurate information than standard 2-dimensional angiography, mainly in terms of adequacy of length assessment. Indeed, 3-dimensional modeling provides coronary segment lengths closer to the actual real length, while 2-dimensional angiography tends to underestimate the real length of the coronary arteries. In addition, in case the coronary anatomy allows percutaneous treatment of the stenoses, stent implantation is considered the optimal management to achieve successful dilatation of these lesions. However, adequate evaluation of the stenting procedure by means of simple angiography is insufficient to determine the quality of the intervention itself, in terms of good expansion of the stent and good apposition of the device to the vessel wall. A novel simple angiographic technique, StentBoost, based on the angiographic enhancement of the intravascular prosthesis deployed, has been recently developed to overcome limitations of standard angiography. Examples of the angiographic result after stent implantation with StentBoost applied to conventional and new percutaneous coronary techniques are shown in the second part of this thesis. StentBoost allows for optimization of the coronary procedure in complex anatomies, such as: 1) percutaneous stenting of a bifurcation lesion with the conventional single stent plus kissing balloon technique, 2) percutaneous treatment of a bifurcation lesion using the novel self expanding conus-shaped biolimus-eluting nitinol Axxess stent, 3) percutaneous treatment of a small vessel with the novel self-expanding sirolimus-eluting nitinol Sparrow stent-in-wire, and 4) percutaneous stenting of a bifurcation lesion with the novel self-expanding bare nitinol Stentys stent system for enhanced provisional bifurcation stenting.