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Balloon angioplasty has become a very successful technique for treatment of coronary artery disease, providing high angiographic and clinical success rates. Limitations of procedures include inadequate dilatation, acute complications such as abrupt closure, acute myocardial infarction, emergency bypass surgery, and death, as well as chronic restenosis. From the procedural standpoint rapid development of chest pain limits balloon angioplasty of proximal stenoses with large regions of myocardium at risk. In most clinical institutions, balloon angioplasty procedures must be kept under 60 s in duration to avoid significant transmural myocardial ischemia, severe angina pectoris, arrhythmias, or a drop in aortic pressure. However, there is suggestive evidence that prolonged inflations of narrowed vascular segments may improve the rate of acute angiographic complications like dissections and abrupt closure, and reduce the chronic restenosis rate as well. An autoperfusion catheter system that allows myocardial perfusion during balloon inflation provides a number of significant advantages, including practically unlimited duration of inflations without angina, improved angiographic and clinical primary success rates, and a wide margin of safety in cases of acute occlusion requiring emergency bypass surgery. The autoperfusion catheter allows clinically significant ongoing blood flow during balloon inflation in both animal and preliminary studies in humans [I]. Inflation with the STACK autoperfusion catheter was maintained for at least 30 min in animal experiments. The resulting prolonged vessel wall ischemia and subsequent damage could potentially create a scarred segment of coronary vessel, which might participate less in the complex proliferative processes that lead to restenosis [1]. |
