he had suffered what has become known as a dvt - a deep vein thrombosis - but he had been operated upon in time , by the best surgeons that money could buy and , after a relatively short convalescence period , had made an almost complete recovery - the only reservation being that it was thought , by the doctors at the time , that he had also suffered a mild stroke , brought on perhaps by the stress of the operation and which had left him , for a few days immediately afterwards , mildly disorientated and locally paralysed in the left-hand side of his face .