Bernie Sanders cancel appearances after heart surgery

US Democratic presidential hopeful Bernie Sanders will cancel campaign appearances for a few days and rest after having two stents inserted to treat a blocked coronary artery that caused chest pain, a campaign official said on Wednesday.

The 78-year-old US senator from Vermont was campaigning in Las Vegas on Tuesday when he felt discomfort, according to his campaign, and he was taken to a hospital where the surgery was performed.

"Following medical evaluation and testing, he was found to have a blockage in one artery and two stents were successfully inserted," said Jeff Weaver, Sanders senior adviser, in a statement.

"Senator Sanders is conversing and in good spirits. He will be resting up over the next few days. We are canceling his events and appearances until further notice, and we will continue to provide appropriate updates," Weaver said.

Sanders, the oldest candidate among the Democrats seeking the party's presidential nomination, has crisscrossed the country with appearances in three or four places each day.

The heart procedure forced Sanders to cancel a scheduled town hall meeting on Wednesday in Las Vegas where he was to discuss gun control. He was also due to make several appearances in California on Thursday and Friday.

His campaign canceled at least $1.3 million in ad spending on Iowa television and radio stations.

The hashtag #GETWELLBERNIE trended on Twitter at midday on Wednesday following news of his surgery.

Some of his presidential rivals, including former vice-president Joe Biden, senators Elizabeth Warren of Massachusetts, Cory Booker of New Jersey and Kamala Harris of California, and South Bend, Indiana, Mayor Pete Buttigieg, were quick to send well wishes on Twitter.

Biden tweeted: "Dr Biden and I are sending our best wishes to Bernie Sanders … 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."

"Thinking of @BernieSanders today and wishing him a speedy recovery. If there's one thing I know about him, he's a fighter and I look forward to seeing him on the campaign trail soon," Harris tweeted.

The next Democratic debate is scheduled for Oct 15 in Columbus, Ohio.

A Pew survey in May indicated that only 3 percent of Democratic voters believed the best age range for a president to be in was in the 70s. Forty-seven percent of those surveyed said they preferred a president in his or her 50s.

One of Sanders' chief rivals, Biden, who is 76, has gotten questions about his age because of his sometimes rambling discourses and uneven answers at debates.

A stent is a wire mesh tube that's inserted into a narrowed coronary artery to prop it open, prevent re-blockage and allow the heart to get the blood flow and oxygen it needs. Around 2 million stents are put into patients per year, according to Harvard Medical School.

In 2016, Sanders got a doctor's note stating that he was in "overall good health''. It said he had no history of heart disease, doesn't smoke and drinks alcohol infrequently.

The note included details of his medical history and health concerns: "gout, mild hypercholesterolemia, diverticulitis, hypothyroidism, laryngitis secondary to esophageal reflux, lumbar strain and complete removal of superficial skin tumors''.

Last month Sanders lost his voice and was forced to cancel events to rest his vocal cords. His campaign attributed it to his "rigorous" schedule. In March, Sanders cut his head on a glass shower door and had to get seven stitches.

Sanders and Biden have pledged to release updated medical records before the Democratic presidential primaries.

Sanders lost to Hillary Clinton in the 2016 Democratic primary.

He had been running second to Biden in most early polls but has fallen into third in recent weeks behind Biden and Warren.

On Oct 2, a Monmouth University national poll showed that Warren, 70, is the party's frontrunner among likely Democratic voters after Biden and Sanders.

Sanders campaign announced on Tuesday that it had raised $25.3 million in the third quarter.