In 2008, Granett et al. claimed a direct detection of the integrated Sachs- Wolfe (iSW) effect by a stacking approach of patches of the CMB, at the positions of identified superstructures. However, the high amplitude of their measured signal seems to be at odds with predictions from the standard model of cosmology. However, multiple questions arise from these results and their expected value : I propose here an original theoretical prediction of the iSW effect produced by such superstructures. I use simulations based on GR and the LTB metric to reproduce cosmic structures and predict their exact full theoretical iSW effect. Expected amplitudes are consistent with the measured signal ; however the latter shows non-reproducible features that are hardly compatible with ΛCDM predictions.