Oscar McKnight

Heart recipient Oscar McKnight says he's alive today because of the ventricular assist device that kept his diseased heart going while he waited on the transplant list.

On a warm California winter day in December 1993, 52-year-old Oscar McKnight Sr. and his wife packed up the family car and left for Texas to spend the Christmas holidays with family. Little did he know that by the time he would return home two weeks later, he'd be fighting for his life.

A nasty virus he caught while on the trip did more than make him cough and wheeze — it had taken aim at his heart and severely damaged its blood-pumping chambers. His doctor gave him the sobering news that he had congestive heart failure, put him in the hospital and immediately placed him on the waiting list for a transplant. The outlook wasn't good.

"They told me I'd probably die before I got a new heart," says McKnight, now 65. "I'm a praying man and I prayed hard. Finally, the medicine they put me on started to work."

McKnight was taken off the waiting list and sustained by the medicine for more than 10 years. His poor health forced him to take early retirement, however, and he decided to move back to his hometown, Jacksonville. In early 2006, when his health began to deteriorate drastically, he was referred to Dr. Daniel Yip, medical director of the heart transplant program at Mayo Clinic.

Yip explained that he'd reached the point where he had to have a new heart. The discussion then turned to the necessity of a ventricular assist device (VAD) — otherwise known as an artificial heart — to keep him alive until he could get the lifesaving transplant he needed. He underwent surgery a week later to have the VAD implanted.

"In his case, the VAD played a vital role as a 'bridge to transplant'," says Yip. "The left ventricle of his heart was damaged to the point where it was too weak to pump blood to the rest of his body. The VAD took over that function, keeping him alive until a heart came available."

About five weeks later, McKnight's prayers were answered. He received his new heart on March 7. Seven months after transplant, McKnight is doing well. He's out walking every day, enjoying time with his two youngest sons and singing with a community choir.

McKnight (center) enjoys singing with his neighborhood community choir.

"I've been so blessed," says McKnight.

VADs are used in three ways. In patients waiting for a heart transplant, they support the failing heart as a "bridge to transplant." In those who have reversible forms of heart failure, a VAD is a "bridge to recovery" because it takes over the pumping work and allows the heart to recover enough to make a patient well enough for a transplant. Finally, a VAD can be destination therapy" for patients who can't have a transplant due to age, obesity or other medical complications. The device is implanted with the goal of helping the heart pump blood for a number of years.

"If VADs were not available, many people would die before undergoing transplant or have a very poor outcome afterwards," says Yip.

The latest generation of VADs are much smaller than their predecessors and give their recipients more freedom by allowing them to leave the hospital. Just five years ago, the devices had to be hooked up to a 400-pound machine that powered them, and patients were unable to go home. Now, some operate with a small battery back carried around the waist or over the shoulders. Others require a small pullalong case similar in size to a carry-on suitcase. Among the newest and smallest VADs is the kind that McKnight had — the Jarvik 2000.

Ventricular assist devices: Older models, like the Heartmate (left), weigh more and take up more room. The Jarvik 2000's (right) functioning mechanism allows it to be smaller. Both are portable and allow patients to go home.

"It fits in the palm of my hand, it's the same size as a C battery and weighs the size of one," says Dr. Lawrence McBride, director of Mayo Clinic's mechanical circulatory support program. "The older devices can weigh as much as a brick and take up much more volume."

The Jarvik 2000 is so small because it's a spinning motor that continuously pushes blood along. Other kinds are larger because they're pumps that fill the heart with blood and empty it. Some patients are candidates for the smaller model; others, depending on their heart's needs, do better with the pumps. Both kinds allow them to go home from the hospital.

Hilliard, Fla., resident Jim Hoffman, 66, underwent years of medical therapy, had both a pacemaker and defibrillator implanted and was in and out of the hospital after a massive heart attack destroyed a third of his heart. By the time he came to Mayo, he was not an immediate candidate for a transplant because years of having a weak heart raised the pressure in his lungs to three or four times above normal. A new heart would have failed because it would not withstand the high lung pressure immediately after being transplanted. Surgeons implanted a VAD to reduce the heart's workload enough to bring down the pressure in the lungs. Two months after the VAD implant, Hoffman was healthy enough for a transplant. On Oct. 1, Hoffman received a new heart.

"Having the VAD gave me a new chance at life," says Hoffman. "Having the freedom to be at home really helped my recovery because I was able to move around and do more. I felt myself getting stronger every day."

(This story first appeared in the November 2006 issue of The Mayo Clinic Checkup, a complimentary newsletter available to anyone interested in the latest news from Mayo Clinic in Jacksonville, Fla.)