VS 156 then BA 588 at Heathrow
Las Vegas → London → Milan
Timetable, London time
16:15VS 156 from Las Vegas at the gate
15:50BA 588 to Milan leaves the gate
23 h 35 apart on the timetable, overnight
BA 588 leaves 23 h 35 after VS 156 arrives on the timetable: more than half a day, so not a connection we count.