ABSTRACT
As stated elsewhere in this book, soon after its introduction as a diagnostic technique, the limitations of coronary angiography in assessing the underlying atherosclerotic involvement of the studied vessel became evident.1-5 Cardiologists have focused on coronary lumenology, despite the dissociation between coronary angiography and clinical manifestations.2 This approach, when allied to facilitated coronary intervention, may lead to the use of the feared ‘oculostenotic reflex’. The implications of using ‘lumenology’ for the grading of coronary disease according to the number of vessels with angiographic stenoses has also been questioned. As remarked by Plotnick,3 clinical decisions based only on the number of vessels exemplify a unidimensional approach to a multidimensional problem, which could be amended if ‘less anatomy and more physiology’ were used in the assessment of ischemic heart disease. It was against this background that intracoronary guidewires fitted with flow velocity Doppler and pressure sensors were developed during the late 1980s and through the 1990s.6,7
How can pressure and Doppler guidewires complement the information obtained during angiography? By far the most common question raised during the review of a coronary angiogram is whether a given stenosis is hemodynamically significant and therefore is a cause of myocardial ischemia. On other occasions, the physician or investigator would like to assess the status of the coronary microcirculation, which can be affected by many conditions and which not only can constitute a cause of cardiopathy but also may interfere with some techniques used for assessment of coronary stenoses. And in which way should these new technologies help the clinician? An ideal physiological assessment of the discussed aspects of coronary circulation should (1) provide information that incorporates different aspects of coronary physiology, (2) be accurate, (3) be independent of changing hemodynamic conditions, (4) be easy to perform, (5) be safe, and (6) be easy to interpret.
