Techniques for Phenotyping Coronary Artery Disease in the Cardiac Catheterization Laboratory for Applications in Translational Research

The catheterization laboratory is an excellent resource for translational research projects requiring phenotypic analysis of coronary artery disease. Coronary angiography, a traditional method of quantifying coronary disease, remains useful for describing the extent and the severity of angiographic coronary disease but is limited by the fact that angiography only depicts the effect of atherosclerosis on the arterial lumen. For this reason, quantitative coronary angiography has been supplemented by intravascular ultrasound and other catheter-based techniques and non-invasive methods for studies involving atherosclerosis progression and regression. Other angiographic based techniques potentially useful in research include the semi-quantification of collateral circulation, thrombolysis in myocardial infarction (TIMI) frame count, and TIMI blush score. The invasive assessment of coronary flow reserve and fractional flow reserve is a valuable adjunctive technique and can be used to precisely quantify the extent of ischemia or the presence of microvascular disease. Intravascular ultrasound (IVUS) is currently considered the gold standard for early diagnosis of coronary atherosclerosis and for measuring plaque burden. The serial measurements of changes in plaque volume over time are a valuable method of discerning plaque progression and regression. Similarly, radiofrequency backscatter IVUS, a relatively new imaging modality, can be used to describe and track changes in plaque composition.