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Objective To evaluate the impact of IVUS guidance on the final volume of contrast agent utilized in patients undergoing PCI. Background To date, few approaches have been described to reduce the final dose of contrast agent in percutaneous coronary interventions (PCI). We hypothesized that intravascular ultrasound (IVUS) might serve as an alternative imaging tool to angiography in many steps during PCI, thereby reducing the use of iodine contrast. Methods A total of 83 patients were randomized to I) angiography-guided PCI or II) IVUS-guided PCI, both groups treated according to a pre-defined meticulous procedural strategy. The primary endpoint was the total volume contrast agent used during PCI. Patients were followed clinically for an average of 4 months. Results The median total volume of contrast was 64.5 ml (interquartile range [IQR] 42.8 – 97.0 ml; minimum 19 ml; maximum 170 ml) in angiography-guided group vs. 20.0 ml (IQR 12.5 – 30.0 ml; minimum 3 ml; maximum 54 ml) in IVUS-guided group (p<0.001). Similarly, the median volume of contrast / creatinine clearance ratio was significantly lower among patients treated with IVUS-guided PCI (1.0 [IQR 0.6 – 1.9] vs. 0.4 [IQR 0.2 – 0.6] respectively; p<0.001). In-hospital and 4-month outcomes were not different between patients randomized to angiography-guided and IVUS-guided PCI. Conclusions Thoughtful and extensive utilization of IVUS as the primary imaging tool to guide PCI is safe, and markedly reduces the volume of iodine contrast, compared to angiography-alone guidance. The use of IVUS should be considered for patients at high risk for contrast-induced acute kidney injury or volume overload undergoing coronary angioplasty.

Objectives: To evaluate the diagnostic performance of a novel computational algorithm based on three-dimensional intravascular ultrasound (IVUS) imaging in estimating fractional flow reserve (IVUS FR ), compared to gold-standard invasive measurements (FFR INVAS ).Background: IVUS provides accurate anatomical evaluation of the lumen and vessel wall and has been validated as a useful tool to guide percutaneous coronary intervention. However, IVUS poorly represents the functional status (i.e., flow-related information) of the imaged vessel.Methods: Patients with known or suspected stable coronary disease scheduled for elective cardiac catheterization underwent FFR INVAS measurement and IVUS imaging in the same procedure to evaluate intermediate lesions. A processing methodology was applied on IVUS to generate a computational mesh condensing the geometric characteristics of the vessel. Computation of IVUS FR was obtained from patient-level morphological definition of arterial districts and from territory-specific boundary conditions. FFR INVAS measurements were dichotomized at the 0.80 threshold to define hemodynamically significant lesions.Results: A total of 24 patients with 34 vessels were analyzed. IVUS FR significantly correlated (r = 0.79; P < 0.001) and showed good agreement with FFR INVAS , with a mean difference of −0.008 AE 0.067 (P = 0.47). IVUS FR presented an overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 91%, 89%, 92%, 80%, and 96%, respectively, to detect significant stenosis. Conclusion:The computational processing of IVUS FR is a new method that allows the evaluation of the functional significance of coronary stenosis in an accurate way, enriching the anatomical information of grayscale IVUS. K E Y W O R D Scomputational fluid dynamics, coronary blood flow/physiology/microvascular function, coronary artery disease, fractional flow reserve, imaging intravascular ultrasound, interventional devices/innovation, quantitative coronary angiography, three-dimensional coronary models