The Pullback Pressure Gradient: A Physiologic Index to Differentiate Focal From Diffuse Coronary Artery Disease.

Fractional flow reserve is the most widely used physiologic index to establish the functional significance of epicardial coronary artery disease (CAD). Fractional flow reserve guides clinical decisions toward or against coronary revascularization based on a single binary decision threshold indicative of myocardial ischemia. CAD pathophysiological patterns can be evaluated by assessing the distribution of pressure losses along the coronary vessel, often displayed as a "pullback curve." Until recently, the information provided by the pullback curves was visually and subjectively interpreted, which is associated with interobserver variability. The pullback pressure gradient is a novel index that addresses this gap by assessing the longitudinal distribution of the CAD, quantifying it on a scale from 0 to 1, with higher values indicative of predominantly focal CAD and lower values of predominantly diffuse CAD. This review provides a comprehensive analysis and critical appraisal of pullback pressure gradient and future directions.