But even with his assistant Neil McDonald taking charge, Blackburn secured a victory over Allardyce's former club thanks to David Dunn's effort and a Sam Ricketts own goal as the visitors secured their first away points of the campaign.
Related ArticlesPremier League actionTelegraph player raterPremier League tablePremier League fixturesSport on televisionAllardyce, who will rest before having the angioplasty procedure on Friday, performed his usual media commitments on Friday morning but received results of tests he underwent later that day on Saturday morning.
After realising he needed surgery, he picked his team, told the players and gave the pre-match team-talk and watched the game at the Reebok Stadium on television.
Matt Taylor's free-kick was deflected onto the bar by Ryan Nelsen and Blackburn broke immediately, with David Dunn running the length of the field to support and hit a shot from Jason Roberts' lay-off that had just enough power to beat Jussi Jaaskelainen and fly in off the post.
Bolton should have drawn level just before the interval when Taylor's free kick was tipped over the bar and the same player failed to hit the target with a header from four yards from Gavin McCann's corner.
The hosts continued to create openings after the restart, with Ricardo Gardner passing up two chances and Kevin Davies and Taylor also missing the target.
Bolton should find themselves well clear of trouble but have won just once at home all season, straining Gary Megson's uneasy relationship with the club's fans, and this was just the kind of game to expose the supporters' anger.
Taylor had another drive pushed wide by Paul Robinson but soon Blackburn made the game safe in the most bizarre circumstances.
A hopeful long ball forward from Brett Emerton saw Jaaskelainen race to the edge of his area but Ricketts thought the goalkeeper was still on his line and headed the ball into an empty net from 25 yards.