Quick guide: purpose, use and interpretation
Purpose. This calculator helps anticipate patient radiation exposure before PCI, from seven planning-stage characteristics, so that radioprotective measures (access choice, low pulse and frame rates, tight collimation, added filtration, staged procedure, skin follow-up) can be planned in advance. It is a decision-support tool derived from a cohort of 10,634 consecutive PCI; it does not replace clinical judgement or real-time dose monitoring.
How it works. Select the patient profile according to the treatment strategy intended after diagnostic angiography; criteria left unselected are counted as absent. The left main, when treated, counts as one vessel. The score (0 to 15) updates instantly with its risk category and the rate of radiation overexposure observed in that category of the cohort. For the selected profile, three gauges display the expected dose (DAP, air kerma, fluoroscopy time), calculated from statistical models built on the whole cohort.
Reading the gauges. The needle marks the expected dose: the median, meaning half of comparable patients receive less and half receive more; the small interval under the number is the 95% confidence interval of this estimate. Colours are anchored on the alert threshold of each metric: green for usual doses, yellow then orange as doses rise, red beyond the threshold (dashed line). The risk figure next to each threshold is the estimated probability that this profile exceeds it, calibrated on the overexposure events observed in the cohort; for high scores, where few such patients exist, a range is shown instead of a single figure.
Interpretation and limits. A high expected dose or risk figure identifies a procedure deserving reinforced radioprotection, not a contraindication. Individual doses vary widely around the expected value, so the figures are planning aids, never guarantees. Estimates come from a single-centre cohort (2008 to 2018) without external validation; procedures should always be guided by real-time dose monitoring.