A Novel Technique for Endovascular Detection and Removal of Radiographic Contrast during Angiography.

Objectives This study aims at in-vitro validation of the principles of endovascular detection of contrast medium and assessing the feasibility of in-vivo detection and removal of contrast during angiography Background. Contrast-induced nephropathy is a growing concern in current percutaneous interventions with increasing lesion complexity and patient comorbidity To address this clinical problem a novel method of endovascular detection and automatic removal of contrast has been developed and is comprised of a catheter-based system with a reflectance-type optical sensor Methods Blood samples were obtained from ovine subjects to characterize the optical response of blood by measuring the reflectance spectrum at varying levels of hematocrit diluted by a contrast agent The results from the in-vitro test were implemented into an In-vivo system An aspiration catheter equipped with a fiberoptic sensor was inserted into the coronary sinus (CS) of 5 canines Contrast was administered through the coronary artery and reflectance signals were recorded at the CS The removal rate was analyzed through 20 specimen collections Results A proportional relationship was found between hematocrit and reflectance intensity in In-vitro test Upon in-vivo detection of contrast the sensor signal showed a 79 5 +/- 9 9% (n = 33) drop from the pre-injection baseline This was highly reproducible and beyond the noise level of baseline, (2 5 +/- 0 9%) enabling automatic activation of the aspiration system The signal duration was 12 2 +/- 3 7 seconds The removal rate of contrast was 59 3 +/- 11% Conclusion The present study validated the principles of endovascular contrast detection and demonstrated the feasibility of an in-vivo catheter-based removal of contrast using reflectance technology