Use Of A Novel “Ultra-ALARA” Radiation Reduction Protocol For "Annual" Catheterization With Coronary Angiography In The Pediatric Transplant Patient

Background
Annual coronary angiography is performed in pediatric heart transplant patients. Reduction in ionizing radiation from fluoro is important. We report our efforts at radiation reduction through the use of our “Ultra-ALARA – As Low As Reasonably Achievable” protocol.

Methods
All cardiac transplant pts < 21 yrs undergoing “annual” cath with RHC, EMB + coronary angiography at our center from 1/12-12/18 were included. A novel ALARA protocol of multiple features: ultra-low frame rates (2-3fps), low fluoro dose/frame (10-18 nGy/frame), use of the “air-gap” technique for patients < 40 kg was used in all cases. Over time the cases were performed in single plane only. Demographics, procedural and radiation levels were collected and analyzed. Single and biplane radiation doses were compared.

Results
167 caths were performed in 40 patients. Median age was 7.9 yrs (1.7- 20.8) and wt 23 kg (8.8-155.4). Median fluoro time was 6.9 minutes (2.6-28.1), air Kerma (K) 27 mGy (7.5-805.6) and dose area product (DAP) 145.3 µGym² (35.25-7580.3). The median # of angios/cath was 8 (5-14), all were of diagnostic quality with median contrast volume of 25 ml (10-64). 33 caths were biplane and 134 PA only (see Table). Air Kerma/kg was lower in PA cases compared to biplane and these pts also received more contrast. No contrast nephropathy was observed. The K and DAP are the lowest of any prior published data for these procedures.

Conclusions
A novel Ultra-ALARA protocol for “annual” caths in pediatric cardiac transplant patients reduced radiation levels without reduction in efficacy or safety. Air Kerma/kg was decreased in singe plane cases; contrast usage was greater in single plane cases.