@JLeslie – From Wikipedia: (emphasis mine).
On September 2, 2004, while campaigning for Kerry, Clinton had an episode of angina and was evaluated at Northern Westchester Hospital. It was determined he did not suffer a coronary infarction, and he was sent home, returning the following day for angiography, which disclosed multiple vessel coronary artery disease. He was transferred to Columbia Presbyterian Medical Center in New York City, where he underwent a successful on-pump quadruple coronary artery bypass surgery on September 6, 2004. The medical team stated, had he not had surgery, he would have likely suffered a massive heart attack within a few months.[30] As a complication of his heart surgery, Clinton underwent a follow-up surgery on March 10, 2005 for a left pleural effusion, removing scar tissue and fluid from his left chest cavity.[31]
On February 11, 2010, he was rushed to Columbia Presbyterian Hospital in New York City after complaining of chest pains, and had two coronary stents implanted in his heart.[32][33][34][35] He has since recovered and become a vegan.[36]
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The biggest lasting effect is a switch to veganism. He’s not a small man, and I can’t imagine it’s easy for him to take in enough vegan food to gain weight.