Standard dosimetry records cumulative radiation exposure in patients/operators during endovascular aortic repair (EVAR) but does not inform the biological consequences of this exposure. The aim of this study was to measure biomarkers of radiation exposure during EVAR.
Lymphocyte counts and dose area product (DAP) were recorded in patients/operators undergoing EVAR. Markers of DNA damage (c;H2AX and pATM) were measured peri-operatively in circulating lymphocytes during open, infra-renal (IEVAR) and complex (branched/fenestrated [BEVAR/FEVAR]) aortic repair. Inter-operator radiation sensitivity was determined by measuring c;H2AX/pATM in blood samples exposed to radiation (100–1000mGy).
The fall in patient lymphocyte count was greater after endovascular (n=118) compared with open repair (P<0.0001, n=35), with prolonged (∼2-fold) count recovery after EVAR (P=0.007). There was ∼5-fold increase in c;H2AX and pATM in patients immediately after IEVAR and BEVAR/FEVAR (P<0.005 for both;n=48), and in operators immediately after BEVAR/FEVAR (P<0.01 for both;n=14), but not IEVAR.
DAP correlated with c;H2AX rise (P<0.02) in patients after EVAR. The c;H2AX/pATM levels had normalised for all patients/operators after 24hrs. c;H2AX/pATM did not rise in either patients or operators after open surgery. Inter-operator (n=6) radiation sensitivity varied significantly (repeated measures 2way-ANOVA, P<0.007).
Our biodosimetry assays suggest DNA damage occurs in patients and operators after EVAR and may be more relevant for gauging the consequences of radiation exposure than standard dosimetry that currently dictates “safe” exposure levels. A better understanding of the processes that increase c;H2AX/pATM and their relation to the lifetime-attributable risk of cancer is important for both operator and patient safety