ABSTRACT
BACKGROUND: Exposure to high doses of radiation during cardiac interventional procedures is associated with increased rates of cataract and cancer in patients and staff members. Thus, reduction of radiation is recommended by international medical societies. The aim of this study was to evaluate, if the lowest reasonable fluoroscopic acquisition setting for electrophysiological procedures using a novel X-ray detector operated at a minimum detector entrance dose per fluoroscopy pulse is feasible and safe. METHODS: 641 consecutive patients (407 m/234f) underwent ablation procedures at our institution between August 2015 and December 2017. All ablations were performed using an Artis Q.zen X-ray system (Siemens, Germany). The first 308 patients were treated using the conventional dose program ("fluoroscopy zen standard"), from October 2016 until December 2017 another 333 patients underwent ablations using the optimized X-ray dosing program "fluoroscopy zen ULD". For the standard program fluoroscopy dose was set to 18nGy/f, for the minimized dosing program the dose was set to 6nGy/pulse and could be increased to 10 or 15 nGy/pulse manually. RESULTS: A total of 213 AV-node reentry tachycardia (AVNRT), 73 accessory pathways (AP), 71 atrial flutter and 284 atrial fibrillation (AF) ablation procedures were performed. Pulmonary vein isolation was performed using an electroanatomic mapping system (CARTO, Biosense Webster, USA) in 117 or a cryoballoon (Cryocath Medtronic, USA) in 167 patients. Total area dose could be reduced in all groups by a mean of 74.7% (4201.4µGym² vs. 1063.7µGym²), with a relative reduction of 73.1% for left atrial and 78.0% for right sided ablations. Total fluoroscopy time, procedure duration, acute ablation success, recurrence rate and complications remained unchanged. CONCLUSION: Fluoroscopy dose could be significantly reduced using an optimized X-ray dosing program in a novel X-ray detector without increasing total fluoroscopy time and without alterations of the incidence of recurrences or complications.
Subject(s)
Arrhythmias, Cardiac/surgery , Fluoroscopy/instrumentation , Accessory Atrioventricular Bundle/surgery , Arrhythmias, Cardiac/diagnostic imaging , Atrial Fibrillation/surgery , Atrial Flutter/surgery , Catheter Ablation/methods , Electrophysiologic Techniques, Cardiac/methods , Feasibility Studies , Female , Fluoroscopy/methods , Germany , Heart Rate/physiology , Humans , Imaging, Three-Dimensional , Male , Middle Aged , Pulmonary Veins/physiopathology , Radiation Dosage , Tachycardia, Atrioventricular Nodal Reentry/surgery , Treatment OutcomeABSTRACT
A detailed structure-activity relationship of C2-symmetric diol inhibitors of HIV-1 protease leads to inhibitor 6 (HOE/BAY 793) which is outstanding in the inhibition of the enzyme and in the inhibition of viral replication in HIV infected cell culture (IC50: 0.3 nM; EC50: 3 nM). There are well defined steric requirements for the design of the side chains P1-P3 of the inhibitors. In addition, all three side chains need to be lipophilic. While the enzyme tolerates hydrophilic substituents in some cases, drastic reductions in anti-HIV activity are observed in cell culture, most likely due to insufficient cell penetration.
