Optimisation of coronary angiography exposures requires a multifactorial approach and careful procedural definition

This study investigates the factors associated with higher doses for both single-plane and biplane procedures and establishes centre-specific 75th percentile levels.

602 patients undergoing coronary angiography in a large hospital at Sydney were recruited to the study, and causal agents for high radiation doses were investigated: gender, procedural complexity, severity of coronary artery disease, presence of coronary bypass grafts, entry approach (radial or femoral), level of operator experience; and a single-plane or a biplane imaging system was employed.

The 75th percentile levels were calculated. The results demonstrated that, for both systems, higher exposures were associated with patients who were male (p<0.001), had coronary vessel disease (p<0.001) and had a history of coronary bypass grafts (p<0.001). In addition, for biplane systems, procedural complexity (p<0.001), types of entry approach (p<0.001) and levels of operator experience (p<0.001) significantly impacted upon the dose. Biplane examinations recorded higher doses than single-plane procedures (p<0.001) and the inclusion of left-sided ventriculography contributed to the overall dose by up to 10%.

The 75th percentile levels in this study represent the tentative reference levels and are 48.9, 44.2 and 56 Gy cm(2) for all exposures, single-plane- and biplane-specific exposures, respectively, and compare favourably with the diagnostic reference level values established elsewhere internationally, with only the UK and Irish data being lower.

Specific agents have been identified for dose-reducing strategies and the importance of operator training is highlighted. The assumption that biplane procedures may reduce the patient dose should be treated with caution.