Pediatric patient radiation dosage during endomyocardial biopsies and right heart catheterization using a standard "ALARA" radiation reduction protocol in the modern fluoroscopic era.

Background: Surveillance endomyocardial biopsy (EMB) with right heart catheterization (RHC) is the standard of care for the assessment of post cardiac transplantation rejection. This procedure has traditionally relied upon fluoroscopy, which exposes both patient and staff to the risks of ionizing radiation. These risks may be of particular concern in the transplant patient who must undergo many such procedures lifelong. We present data on a new "ALARA - As Low As Reasonably Achievable" protocol to reduce radiation exposure during the performance of RHC with EMB.

Methods: All cardiac transplantation patients < 21 years of age who underwent RHC with EMB at The Children's Hospital at Montefiore from 6/11-12/11 were included. EMB was performed after all right heart pressures including wedge pressure and thermodilution cardiac output were measured. A novel ALARA protocol consisting of multiple features including ultra-low frame rates (2-3 fps), low fluoro dose/frame (10-18 nGy/frame), use of the "air-gap" technique for patients < 20 kg, and multiple other techniques aimed at minimizing use of fluoroscopy were employed in all cases. Demographics, procedural data and patient radiation exposure levels were collected and analyzed.

Results: 18 patients underwent 45 surveillance RHC with EMB in the study period and were the subject of this analysis. The mean age was 5.9 ± 6.1 years, weight was 20.4 kg ± 16.6 kg, and BSA was 0.75 ± 45 m(2) . PA fluoroscopy was used exclusively in 45/45. Vascular access was RFV (21/45; 47%), RIJV (17/45; 38%), LFV (4/45; 9%) and LIJV (3/45; 7%). The median number of EMB specimens obtained was 5 (range, 4-7). The median fluoroscopy time was 3.7 min (range, 1.2-9). The median air Kerma product (K) was 1.4 mGy (range, 0.4-14), and dose area product (DAP) was 15.8 uGym(2) (range, 3.5-144.5). The K and DAP are substantially lower than any prior published data for RHC/EMB in this patient group. There were no procedural complications.

Conclusions: The use of a novel ALARA protocol for RHC and EMB in pediatric cardiac transplantation patients markedly reduced radiation exposure to levels far below any previously reported values without negatively affecting the safety or efficacy of these procedures.