WASHINGTON -- Vice President Dick Cheney's recent episodes of chest pain were caused by a complication that occurs fairly frequently among patients who have undergone the kind of treatment Cheney received in November to restore blood flow to his heart, experts said Monday.
Cheney developed a renarrowing of the small artery in his heart that doctors opened last November, a complication that occurs in about one out of five patients who have a stent -- a hollow, spring-like device -- implanted inside a narrowed heart artery.
Doctors at George Washington University Hospital inflated a small balloon inside the affected artery Monday to open the area that had narrowed at one end of Cheney's stent. Whether the problem will occur again, causing additional bouts of chest pain, is impossible to say, but Cheney's cardiologist, Jonathan Reiner, estimated the chance of a recurrence at around 40 percent.
Even if the affected vessel were to close off completely, it is so small that it would be unlikely to cause a major heart attack, said Eric Topol, chairman of cardiology at the Cleveland Clinic, who is familiar with Cheney's case. He said it probably is also too small for doctors to subject Cheney to the risk of a second bypass operation to fix it.
Cheney, who has had four heart attacks, underwent quadruple bypass surgery in 1988. His doctors evaluated the bypass grafts after his latest heart attack last fall and said they were all open and functioning.
Cheney's doctors said in a briefing Monday night that the vice president has adhered faithfully to his diet, exercise and medical regimen. The renarrowing of the artery at the opening of the stent was caused by rapid scarring that can occur when a foreign body is placed in a blood vessel. It is different from the narrowing caused by the deposits of cholesterol that accumulate gradually in the arteries of people with heart disease.
"There aren't any things that we know today that reduce renarrowing, in terms of diet, medicine or lifestyle," said Topol. "It kind of has a mind of its own."
Starting on Saturday, Cheney experienced four brief episodes of chest discomfort, including two on Monday that lasted three to five minutes each, Reiner said. Such symptoms are typical when renarrowing develops at the site of a stent, and were very different from the severe, prolonged chest pain that the vice president suffered during a heart attack last November, he said.
Blood tests done when Cheney was admitted to the hospital Monday were normal, showing no evidence of a heart attack, Reiner said. Cardiologists performed a procedure called a cardiac catheterization -- injecting dye into the arteries of the heart and taking X-rays -- and found "a very discrete spot of renarrowing," about a millimeter long, at one end of the stent, which is about 13 millimeters long.
The doctors threaded a balloon into the artery and inflated it to dilate the narrowed area. They used an ultrasound device to examine the rest of the stent and found it was in good shape, Reiner said.
Nevertheless, cardiologists cautioned that if the narrowing occurs again, it could provoke additional episodes of chest pain that may interfere with the vice president's activity and require further treatment.
Once a patient develops renarrowing at the site of a stent, studies show the risk of recurrence is as high as 50 percent to 60 percent when the problem is treated with a balloon or laser, said Lowell Satler, director of coronary intervention at the Washington Hospital Center. The risk appears to be lower if the problem is treated with brachytherapy, a type of radiation therapy recently approved by the Food and Drug Administration, he said.
Topol said the long-term risk of brachytherapy is unknown, and that Cheney's doctors took a conservative approach by using a balloon. Radiation could be used if the problem recurs, he said.
Reiner said he saw Cheney for a routine appointment last week and increased the dose of one of his medicines, a drug known as an angiotensin-converting enzyme (ACE) inhibitor. He also said Monday that the vice president is on Plavix, an anti-clotting drug. Topol said Cheney is getting state-of-the-art preventive therapy, which he said would also include a beta blocker and a medication called a statin to lower cholesterol.
Brainerd Dispatch ©2013. All Rights Reserved.