Reduction of radiation exposure associated with renewal of the radiologic systems in coronary interventions.

PURPOSE: Interventional coronary procedures are an important source of radiation. This study sought to evaluate the effect of the renewal of the radiologic system on patient exposure during diagnostic coronary angiography (DCA) and percutaneous coronary interventions (PCIs). METHODS: DCA and PCIs were obtained from three centres, which renewed their radiologic systems during their participation in the multicentre prospective observational RAY'ACT-2 study. Data were analysed from the months before and after the radiologic system was changed. The primary outcomes were the dose reduction estimated by the kerma.area product (KAP in Gy·cm2) and the ratio of the KAP to fluoroscopy time (Gy·cm2·min-1). RESULTS: A total of 2148 patients underwent DCA (1575 before and 573 after the system change), and 1563 underwent PCI (1196 before and 367 after). A change in the radiologic system was associated with a KAP reduction of 43% for DCA (median [interquartile range]: 18.1Gy·cm2 [10.2-34.0] versus 31.5 [19.0-49.0], P<0.0001), and 38% for PCI (42.2Gy·cm2 [23.8-81.7] versus 70.1 [42.0-109.0], P<0.0001). Fluoroscopy time did not vary significantly, and the ratio KAP to fluoroscopy time significantly decreased by 54%. The dose reduction was homogeneous between the three centres and between different manufacturer's systems. CONCLUSIONS: In this multicentre study, the renewal of the radiologic system was associated with a highly significant 40%-50% reduction in radiation dose, irrespective of the manufacturer. A close interaction between manufacturers and operators is needed to optimise the use of new equipment and the effectiveness of radiation reduction tools and techniques.

[Measurement of fractional flow reserve in patients with severe aortic stenosis: A valid test?] / Sténose aortique et lésions coronaires : la fractional flow reserve (FFR) est-elle valide ?

A 54-year-old woman was hospitalized for an acute pulmonary oedema revealing a severe aortic stenosis (AS) associated with an aortic aneurysm and a left ventricular hypertrophy (LVH). The coronary angiography found an equivocal left main lesion. Fractional flow reserve (FFR) showed hemodynamic significance (FFR=0.78) and optical coherence tomography confirmed this result with a minimal lumen area of 4.9mm2. FFR-guided percutaneous intervention is reported to improve outcome in patients with stable coronary disease. However, only few data are available in cases of AS. In this condition, secondary LVH is associated with microcirculatory dysfunction, which interferes with optimal hyperemia. An elevated right atrial pressure could also modify FFR measurement. This risk of underestimation of a coronary lesion in patients with severe AS has to be taken into consideration in clinical practice.