Advances In Quantitative Coronary Arteriography

In this fourth book in the series on quantitative coronary arteriography (QCA) with the earlier three volumes published in 1986, 1988 and 1991, the latest developments in this exciting field are covered. Both the methodolog ical and clinical application aspects of these advances are presented in a comprehensive manner in a total of 37 chapters by world renowned experts. The book is subdivided into a total of eight parts, beginning with the more methodological issues, such as QCA and other modalities (3 chapters), cine film versus digital arteriography (3 chapters), quality control in QCA (4 chapters), and coronary blood flow and flow reserve (3 chapters). Since QCA has been well established as the technique for the assessment of regression and progression in atherosclerotic disease, and of restenosis after recanaliz ation procedures, major clinical trials in both groups are described extensively by their principal investigators in a total of 11 chapters. In addition, the QCA results after the application of various recanalization techniques are presented in another eight chapters. In the last part the experiences with various intracoronary prostheses with the emphasis on QCA are discussed in five chapters. This large increase in application oriented chapters means that QCA is well alive and gaining momentum. Although the accuracy and precision of the analytical methods steadily improve with the increasing complexity of the algorithms, there is still always the human factor involved in these processes in terms of frame selection, segment definition, etc.

Over the past twenty years, technical advances in coronary arteriography have contributed to our understanding of the pathophysiologic aspects and natural history of coronary artery disease. Probably more than 700. 000 coronary arterio grams are performed annually throughout the world. Usually, these arteriograms are interpreted visually to determine the morphologic extent and severity of coronary artery disease. These subjective determinations, which are hampered . by relatively large intra- and interobserver variations, are used as a basis for critically important therapeutic decisions: Which arteries are to be revascular ized, which lesions are suitable for coronary bypass surgery or for percutaneous coronary angioplasty? To improve on this clinical decision making, on the treat ment and follow-up of such patients, new, objective and reproducible techniques for the assessment of the extent and severity of coronary artery disease, both in terms of anatomy and functional significance of the lesions, must be made widely available. With such new procedures and technologies the efficacy of new thera peutic procedures, the effects of vasodilating and constricting drugs, and the results of long-term studies on the regression and progression of atherosclerotic plaque can be determined in an objective and cost-effective manner.

This is the fifth volume in this series on quantitative coronary arteriography (QCA) published over the last nine years. Research and applications in this exciting, field are covered in a total of 26 chapters by world renowned experts. This book is subdivided into a total of 6 parts, each emphasizing the latest progress in these respective fields. In Part One a comprehensive overview is given of the current knowledge and research in endothelial function, which is of eminent importance for the further understanding of the pathophysiology of coronary artery disease in patients. Fortunately, the use of QCA tools is not limited anymore to leading research institutes; over the last several years these tools have been installed in many cardiology centers world wide. To understand the current possibili ties, limitations and future expectations of QCA, several relevant topics are presented in Part Two. First of all, the questions about why and how QCA systems should be validated both at the development site and at the appli cation sites, and whether data from different vendors and core laboratories can be pooled, are discussed. As the X-ray cardiovascular world steadily moves into the digital imaging era, differences and similarities between the conventional cinefilm and the modern digital approaches are presented. Cur rently. the widespread use of digital imaging is still hindered by the lack of proper archival and exchange media. Requirements and possible solutions for this problem are handled in this section as well.

There are few techniques that have influenced therapeutic strategies in modem cardiology to a similar extent as coronary arteriography. Bypass surgery as well as transluminal coronary angioplasty would not have been possible without coronary angiography serving as a 'midwife' in their evolu tion. Despite the widespread and long-standing use in clinical practice, however, the interpretation of coronary angiograms has not changed very much since the early days. Most angiogr~s are still reviewed in a visual and semi-quantitative and thus often very subjective way. In the face of an almost exploding field for interventional catheterization including thrombolysis, balloon dilatation, and other rapidly evolving techniques for transluminal revascularization or recanalization, a more detailed and quantitative analysis of coronary arteriograms is urgently required. In addition to the delineation of coronary morphology, we need dynamic and functional information about flow and perfusion to understand the physiological significance of anatomic abnormalities. Coronary arteriography contains and can provide most of this information. With the application of appropriate techniques, it can be made available in the catheterization laboratory even during the patient's investiga tion, thus facilitating and improving clinical decision making. Objective and reproducible analysis will furthermore enhance our understanding about the pathophysiology of coronary disease.

In June 1989, a third conference concentrating on the progress in quantita tive coronary angiography and related techniques was held in Rotterdam, again very successful as the two preceding events in 1985 and 1987. Tech nical as well as clinical aspects of digital and digitized coronarography, morphometry, parametric imaging and functional quantification of the human coronary circulation were presented and discussed by prominent exponents of those groups who have been active in this particular field for many years. This book contains the chapters representing the lectures held by leading experts during the symposium that update the knowledge currently available, including most recent aspects in angioscopy and intravascular ultrasound imaging. It also includes a historical review on the development of angiogra phic techniques from the very early days on to our times given by one of the pioneers in heart catheterization and angiography, Dr. Kurt Amplatz. Those who had the chance to listen to his talk, will surely remember his impressive, humorous lecture as one of the highlights of this meeting.

Quantitative coronary angiography has become an invaluable tool for the interventional cardiologist, providing objective and reproducible measurements of coronary artery dimensions, which can be used to study progression or regression of coronary atherosclerosis, as well as the immediate and long term effects of percutaneous interventions. Until recently, this powerful imaging technology was confined to a small number of so-called high level institutions. Fortunately, with the development of digital cardiac imaging equipment and adaptation of cine-angiographically based computer software for on-line use in the catheterization room, quantitative coronary angiography is now available to all interventionalists. This book is a timely guide for the impending QCA user, providing practical as well as theoretical and scientific information. A comprehensive evaluation of the clinical usefulness of QCA is covered, from the fundamental principles through experimental validation studies, application to clinical trials of a wide range of pharmacological and interventional therapies in the full spectrum of clinical presentation of coronary disease syndromes, evaluation of the therapeutic efficacy of various new devices for coronary intervention, together with extensive presentation of its physiological, functional and anatomical correlations, by comparison with other intracoronary measurement and imaging techniques. In addition, evolving theories and concepts in the ever topical `restenosis phenomenon' after percutaneous intervention, based on serial QCA studies, are presented and discussed and a potentially unifying methodological approach to further study of this ubiquitous problem is offered. This book, thanks to the collaboration of many experts in the field of intracoronary imaging and measurement, provides stimulating, interesting and practical information, both for the academic scientist and practising clinician.

In the intervening 10 years tremendous advances in the field of cardiac computed tomography have occurred. We now can legitimately claim that computed tomography angiography (CTA) of the coronary arteries is available. In the evaluation of patients with suspected coronary artery disease (CAD), many guidelines today consider CTA an alternative to stress testing. The use of CTA in primary prevention patients is more controversial in considering diagnostic test interpretation in populations with a low prevalence to disease. However the nuclear technique most frequently used by cardiologists is myocardial perfusion imaging (MPI). The combination of a nuclear camera with CTA allows for the attainment of coronary anatomic, cardiac function and MPI from one piece of equipment. PET/SPECT cameras can now assess perfusion, function, and metabolism. Assessing cardiac viability is now fairly routine with these enhancements to cardiac imaging. This issue is full of important information that every cardiologist needs to now.