By: Jean Johnson for Veins1The Food and Drug Administration (FDA) might not have approved the technology – stent grafts – yet, but that didn’t stop Vice President Dick Cheney from choosing the minimally invasive procedure to repair bulges in the arteries behind his knees. Under a local anesthetic and with a one-day hospital stay, Cheney had both knee arteries repaired and was resting well enough at home to receive an afternoon briefing on the impact of Hurricane Rita in Louisiana and Texas. Still, some experts are puzzling over his choice of treatment, with a number worrying that complications may result down the line.
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Perks and Concerns about Stent Grafts
Perks:
Minimally-invasive surgery
Local anesthesia
One day hospital stay
Concerns:
Not yet approved by the FDA
Stent grafts would receive considerable stress located in the knee.
Lack of long term studies to confirm the durability of stent grafts.
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“Using local anesthesia, two overlapping Viabahn stent grafts were implanted in the right popliteal artery,” the statement from Cheney’s office said. “Placement of the device in the right knee artery went exceedingly smoothly, and an intraoperative decision was made to repair the aneurysm behind the left knee using a similar technique.” While it is unusual to do both knees at once, Cheney’s office reports that the medical team felt the move was appropriate given the vice president’s circumstances. Sixty-four year old Cheney has a history of circulation issues including four heart attacks – the first at age 37 in 1978, and the last in 2000 after the contested presidential election. He was fitted with a pacemaker in 2001, and in July 2005 his physicians found he had weakened spots or aneurysms in the popliteal arteries behind each knee.
Aneurysms that develop painlessly in any number of arteries in the body tend to burst and cause strokes and other problems related to internal bleeding. But when aneurysms occur in the popliteal arteries behind the knees, the more typical danger is the formation of blood clots that can cut off blood supply to the leg. Once clots have developed, the only treatment is amputation, a fate Cheney clearly wished to avoid.
While vascular surgeons have a successful, well established technique for treating aneurysms in the knee arteries, recovery time can be extensive from open surgeries that dissect down through body structures with a scalpel. Perhaps Cheney went with interventional radiology to avoid prolonged down time or any number of other complications, like infection, that general surgery can entail.
Interventional radiologists are experts on the circulatory system. They diagnose and treat problems with catheters inserted through tiny nicks in the skin. The catheters in turn have tiny cameras and surgical instruments attached so the interventional radiologists work internally via real time imaging screens.
While many interventional radiology techniques like uterine fibroid embolization are well established, the procedure Cheney’s medical team used is considered experimental by many because the FDA has not approved the stent grafts yet.
Vascular surgeons across the country told The New York Times their concern was “that a stent graft would be subject to far more stress in the knee, from bending and extension, than when placed in other arteries. Few long-term studies have been conducted to determine its durability,” stated a group that includes Eugene Zierler, M.D., vascular surgeon at the University of Washington; Peter Kalman, M.D., director of peripheral vascular surgery at Loyola University Medical Center in Maywood, Illinois; Craig Kent, M.D., chief of vascular surgery at New York’s Weill Cornell Medical Center; and Thomas Bernik, M.D., chief of endovascular surgery at St. Vincent’s Hospital Manhattan.
That said there has been a substantial history of difference of opinion between traditionally trained surgeons and interventional radiologists over the efficacy of the minimally invasive approaches.
The interventional radiology procedure “relined the blood vessel and should wall off clots that have already formed in the dilated areas,” said Kim Hodgson, professor and chairman of the division of vascular surgery at Southern Illinois University School of Medicine. “The bigger issue is in the long run will these grafts continue to function well for him. The issue down the road is does this vessel stay open and the graft stay in place.”
Frank Veith, M.D. and vice chairman of surgery at Albert Einstein College of Medicine in New York noted that the procedure performed on Cheney was “pretty safe and simple” but he agreed with Hodgson that if the arteries were large and twisted “bad things can happen and they don’t necessarily need to happen right away.” Should the stent grafts, or the tubes implanted to help blood flood through a weakened artery, fail and clots form, Veith said “the leg won’t feel right. There will be pain on walking and pain at rest.”
The vascular surgical community that Veith and others represent uses sutures around the aneurysm to prevent clots from escaping. Their standard surgical operation, they point out, doesn’t always require general anesthesia and can sometimes be done under a regional anesthetic. Also, the surgeons explain that that their procedure that requires removing a piece of saphenous vein from the leg to use as a bypass shunt around the aneurysm has stood the test of time. They generally do not repair both legs at once, however, allowing sufficient healing time in one limb before treating the second.
Members of the interventional radiology community have not been as vocal over the Cheney procedure as those from vascular surgery. Perhaps that’s because the FDA has not approved the stent graft yet, and there is a lack of long-term results for the procedure.
Craig Kent, though, said he knew the team of physicians involved in Cheney’s case to be medically conservative. More, Stephen Schmidt, Cheney’s chief spokesman said the vice president underwent extensive pre-procedure counseling and was comfortable with his choice of treatment options.
Anthony Venbrux, M.D. and director of interventional radiology at George Washington Hospital headed the multidisciplinary team that performed Cheney’s procedure. Venbrux worked with Jonathan Reiner, M.D., director of the cardiac catheterization laboratory, and Joseph Giordiano, chairman of surgery. Barry Katzen, M.D., director of the Baptist Cardiac and Vascular Institute in Miami and Peter Gloviczki, M.D., chair of vascular surgery at the Mayo Clinic were also present.
Cheney has mended his ways since circulatory problems started impinging on his health. He is reported to have given up smoking after his latest heart attack in 2000. His office also says he exercises daily and takes a cholesterol-lowering medication. With these healthy lifestyle choices in place, the vice president’s long-term benefits not only from the interventional radiologist’s approach to treating his knee aneurysms, but also from all the other cardiac care he’s had over the years should increase many times over.
