'On-Pump' Heart Surgery Gets High Marks
Study Prompts New Debate Over Bypass Surgery With and Without Heart-Lung Machine
Nov. 4, 2009 -- Coronary artery bypass surgery performed on a beating heart
without the aid of a heart-lung machine proved no more effective than
traditional bypass surgery, a study comparing the two procedures shows.
Roughly 1,000 patients treated at 18 Veterans Administration hospitals
across the country received beating heart, or "off-pump" bypass surgery. A
similar number received "on-pump" surgery, performed while their hearts were
The two treatment groups had similar outcomes with regard to survival and
medical complications within 30 days of surgery.
But composite outcomes a year later appeared to favor the on-pump procedure;
the off-pump surgery offered no advantage in terms of neurological outcomes,
such as memory loss and concentration.
The study appears in the Nov. 5 issue of TheNew England Journal
These days, about one in five coronary artery bypass graft (CABG) patients
in the U.S. get the off-pump surgery.
Cardiovascular surgeon and study co-researcher Frederick Grover, MD, of the
University of Colorado, Denver, tells WebMD that he doesn't expect this number
to drop drastically as a result of the findings.
"I would expect surgeons who are expert at performing the [off-pump]
procedure and who are getting excellent results to keep doing it," he says.
"But I imagine that at some institutions, fewer of them will be done."
Beating Heart Bypass
First performed a little over a decade ago, the beating-heart CABG procedure
became popular because it was widely believed to be associated with fewer
postsurgical physical and cognitive complications.
With CABG, a blockage or area of severe narrowing in a coronary artery is
bypassed with a piece of vein or artery called a graft. The graft is connected
above and below the blocked area so that blood flow is restored.
Usually patients needing bypass surgery will have more than one blood vessel
that requires a graft. The process of re-establishing blood flow in blocked or
severely narrowed vessels is referred to as revascularization.
Bypass has been linked to complications such as memory loss, muddled
thinking, and concentration problems lasting weeks to months after surgery.
Placement on a heart-lung machine has been implicated, but not proven, as a
possible contributor to this cognitive impairment.
The VA study was designed to compare cognitive and physical outcomes with
the two procedures at 30 days and one year post-treatment.
Researchers randomly assigned 2,203 patients scheduled for urgent or
elective CABG to the beating heart or stopped-heart procedures.
"Our trial did not show any overall advantage to the use of the off-pump as
compared with the on-pump cardiac surgical approach for coronary bypass," the
researchers write. "Instead, there was a consistent trend toward better
outcomes in patients undergoing conventional on-pump CABG technique."
Almost all of the patients in the VA study were men and they tended to be
younger (average age 63) and low to moderate risk. Because of this, it is not
clear if the off-pump procedure offers advantages for women or for older and