Las Vegas: Sen. Bernie Sanders had a heart attack this week, his presidential campaign said Friday as he left a Las Vegas hospital, following three days of near-silence from the candidate and his advisers about his health.

Sanders, 78, had entered the hospital Tuesday night after experiencing chest pain at a campaign event, and doctors had inserted two stents in a blocked artery, a relatively common procedure. But the campaign did not confirm that Sanders had a heart attack until Friday, inviting questions about his condition, and his campaign’s transparency, as he remained off the campaign trail this week.

Television cameras filmed Sanders as he left the hospital Friday, waving to onlookers and pumping a fist, then driving off in a sport utility vehicle. He will remain in Las Vegas on Friday night and return to his home in Burlington, Vermont, on Saturday, campaign officials said.

“After 2 1/2 days in the hospital, I feel great, and after taking a short time off, I look forward to getting back to work,” Sanders said in a statement.

While much of the conversation in the Democratic race has centred on issues like health care and student debt, Sanders’ heart attack is likely to heighten scrutiny on age in a primary where the top candidates are all in their 70s. In addition to Sanders, former Vice President Joe Biden is 76 and Sen. Elizabeth Warren is 70. President Donald Trump is 73.

But if Sanders has until this week largely avoided questions about his health — he has projected an image of fitness as a candidate and has maintained a blistering schedule on the campaign trail — the spotlight is now squarely on him. The ages of the current leaders notwithstanding, many Democratic voters have expressed discomfort with nominating a septuagenarian candidate, a notion that some political strategists say Sanders’ heart attack is unlikely to dispel.