NEW YORK - Bernie Sanders put his bid for the Democratic presidential nomination on hold Wednesday after being treated for a blocked artery, becoming the first in a race dominated by septuagenarians to halt their campaign for health reasons.
At 78, the leftist senator from Vermont is the oldest candidate vying to take on President Donald Trump in 2020 and one of the leading contenders behind favorites Joe Biden and Elizabeth Warren.
Sanders' team said he was canceling events and appearances "until further notice" after complaining of chest pains while on the stump in Las Vegas, Nevada on Tuesday.
Sanders later wrote on Twitter that he was "feeling good."
"During a campaign event yesterday evening Sen. Sanders experienced some chest discomfort," Sanders' senior advisor Jeff Weaver said in a statement.
"Following medical evaluation and testing he was found to have a blockage in one artery and two stents were successfully inserted."
He added that the senator was talking and in good spirits, and would be resting over the "next few days."
Sanders -- a self-described Democratic socialist -- pushed 2016 Democratic candidate Hillary Clinton right to the wire three years ago and is sitting third in the polls this time around.
He was one of the first to argue loudly for taxing the rich and for the introduction of universal health care, policies now embraced by some of the other candidates.
His Democratic rivals rushed to wish Sanders a swift recovery.
"Anyone who knows Bernie understands what a force he is. We are confident that he will have a full and speedy recovery and look forward to seeing him on the trail soon," tweeted Democratic frontrunner Biden.
Warren, a senator from Massachusetts, tweeted that she hoped "to see my friend back on the campaign trail very soon," while Kamala Harris said she was "thinking" of Sanders.
Sanders thanked well wishers and used the opportunity to trumpet one of his key election pledges.
"I'm fortunate to have good health care and great doctors and nurses helping me to recover," he tweeted.
"None of us know when a medical emergency might affect us. And no one should fear going bankrupt if it occurs. Medicare for All!"
Sanders has served in Congress as an independent aligned with Democrats since 1991, first as a representative of Vermont and then, since 2007, as the state's junior senator.
Earlier this year he was running consistently in second place behind former vice president Biden, who is two years younger, in the race for the Democratic Party nomination for president.
Since July, he has jockeyed for position with Warren, who recently moved slightly ahead of him in polls in the crowded field.
Both Sanders' and Biden's age has been raised as an issue in their candidacies. Trump is 73, while Warren is 70.
Sanders' health has generally been good for his age, however, and it has been Biden who has had to bat away questions about his stamina and mental sharpness.
In March, Sanders gashed his head on a shower door and had seven stitches, but quickly returned to the campaign trail.
Last month, he canceled three events in South Carolina to rest his voice, which had become hoarse.
Sanders sounded raspy during the third Democratic debate and his campaign said it was because of a "vigorous campaign schedule."
New York congresswoman Alexandria Ocasio-Cortez said Sanders' hospitalization highlighted the rigors of running for office.
"A lot of people don't understand how crazy hard grassroots campaigning is -- for organizers and candidates alike. Rest up, friend. We're with you!" she wrote on Twitter.
Sanders faces a long and bruising battle ahead, with the first Democratic primaries not taking place until February.
He is currently third in an average of national polls, with 16.7 percent, according to RealClearPolitics.
Biden leads at 26.1 percent, with Warren second with 24.4 percent.
It was not immediately clear whether Sanders would be fit to appear in the fourth Democratic debate scheduled for October 15 in Ohio.
Trump, who likes to tout his own health, famously mocked Clinton when she became ill during a 9/11 memorial ceremony in 2016.
The president did not immediately comment on Sanders' announcement.
© Agence France-Presse