Intravascular Ultrasound Findings Associated With Hydrodynamic Contrast Recanalization (HDR) of Coronary Chronic Total Occlusions

Background Hydrodynamic contrast recanalization (HDR) is a novel technique to facilitate wire crossing during chronic total occlusion (CTO) percutaneous coronary interventions (PCI). The mechanisms underlying HDR have not been fully described. Aims To investigate the impact of HDR on plaque morphology and wire tracking during CTO PCI using intravascular ultrasound (IVUS) imaging. Methods We identified 35 patients who underwent successful HDR and IVUS‐guided CTO PCI at our institution between January 2023 and December 2024. We collected the following from IVUS images: wire position (intraplaque vs. extraplaque) within the CTO segment, plaque morphology, and evidence of vascular injury (intramural hematoma or dissection). Results Immediate post‐HDR IVUS images were available for analysis in all 35 patients. IVUS imaging revealed intraplaque guidewire crossing in 91% ( n = 32) of cases. Intraplaque speckling, which we have termed the “Starry Sky” sign, was observed in 24 cases (68%), and intramural hematoma was found in 11 cases (31%). Four dissections were detected: two precluded direct distal wire re‐entry necessitating the use of non‐HDR techniques (94% technical success). The overall procedural success rate was 100%, and there were no PCI‐related complications (perforation, myocardial infarction, or death). Conclusions HDR is a novel CTO PCI technique that appears to facilitate intraplaque wire crossing without causing significant vessel injury. The presence of speckled plaque by IVUS is a unique feature of HDR that may suggest a mechanism underlying this technique. Additional studies are needed to confirm these findings.