(U.S. Vice President Dick Cheney speaks at the National Press Club in Washington, DC, in this June 13, 2005 file photographs. Photo: Reuters)

US Vice President Dick Cheney will undergo an elective surgery next weekend to treat an aneurysm in an artery behind his right knee.

The condition, discovered earlier this year during a routine checkup, needs to be treated "as to not become a problem over time," Steve Schmidt, counselor to the vice president, said Friday.

"The procedure will be performed under local anesthetic," Schmidt said. "It will take place next weekend. It will involve a short hospital stay. The vice president will return to work shortly thereafter."

Schmidt said more details will be announced next week.

Cheney, 64, has had four heart attacks, though none since he became vice president in 2001. That year, he had an implantable cardioverter defibrillator inserted in his chest. The pacemaker starts automatically if needed to regulate his heartbeat.

An aneurysm is a ballooning weak spot in an artery that, as blood pounds through, can eventually burst if left untreated.

Those in the knee, popliteal aneurysms, act a little differently. They're less likely to burst than are aneurysms in other parts of the body. But blood clots can form in the weakened artery that can break off and cause a stroke, or block circulation in the leg.

Typical surgical repair is to open the leg and sew a fabric patch onto the artery to reinforce the weak spot.

A vascular exam, part of a two-part annual physical Cheney completed in July, identified "small, dilated segments of the arteries behind both knees." But his overall cardio health was judged as good after the first part of the exam, which included a general physical exam, an electrocardiogram and a stress test.

The checkup determined that the pacemaker was working well and never had to be activated.