Off-pump, beating-heart coro-nary artery bypass graft surgery has kept on ticking despite a mound of inconclusive studies of its benefits.
Short of minimally invasive surgery, the roughly 6-year-old procedure (often referred to as CABG and pronounced cabbage) is kind of a low-tech solution to a high-tech problem. It eliminates the need for a heart-lung bypass machine in a risky surgery where clogged coronary arteries are bypassed to improve blood flow to the heart, but the trade-off is that the procedure demands greater precision from the surgeon.
In theory, performing surgery on a patient's beating heart without the safety net of a heart-lung bypass machine nevertheless should reduce deaths, hospital lengths of stay and complications such as infections associated with blood transfusions--all of which help reduce costs. Proving that theory has been daunting, with a host of variables at play such as the age and health of the patient and the expertise of the surgeon. The impracticality of large, double-blind, randomized clinical trials whose volunteers are heart-disease patients facing life or death consequences have made such studies almost nonexistent to date.
But a study released exclusively to Modern Healthcare provides the first concrete evidence that this emerging technique is poised to hatch out of its shell into the mainstream of open-heart surgery. After analyzing hundreds of thousands of open-heart surgery cases, the study, possibly for the first time, has uncovered some hard data that solidly validates the procedure.
Perhaps most significantly, the researchers have tracked how outcomes over the three-year study period have significantly improved as cardiac surgeons have scaled the steep learning curve involved in performing the more precise off-pump procedure. Taken in total, the study offers the first powerful rationale for employing the newer surgical technique regardless of a patient's age or health.
Solucient, an Evanston, Ill.-based healthcare information and research company, conducted the first-of-its-kind study at the request of Modern Healthcare.
The study found, as have others, that length of stay and cost per case of on- vs. off-pump bypass surgery are essentially equivalent. But deaths from the procedure, which started out higher for off-pump, have declined to the point where off-pump surgery results in fewer deaths on a risk-adjusted basis, according to Solucient's data.
Overall, during the three-year period, more patients died as a result of the off-pump procedure. Yet, taking a microscopic look at the historical trend, Solucient found that the mortality rate for the newer procedure was declining, presumably as surgeons gained greater experience along with higher volumes. After the data are adjusted for patient age, the break-even point appeared to occur in mid-2000. In general, unadjusted deaths as a result of the off-pump procedure have declined dramatically from a high of 3.82% in the early part of the study to a low of 2.18% in the latter part (See chart). Meanwhile, unadjusted deaths from the on-pump procedure have remained fairly constant, fluctuating from 1.97% to 2.39%. When death rates are risk-adjusted for older, sicker patients, the outcomes look better for off-pump surgery than on-pump surgery.
"This data is showing a measurable advantage to the off-pump procedure on risk-adjusted mortality," says David Foster, Solucient's vice president of clinical informatics and the lead author of the study. "Our overall rates were showing a higher risk of mortality in off-pump, but since this study by design is looking at the historical results of this procedure, we've seen a fairly dramatic change in the risk of mortality as people are becoming more proficient. It seems clear now that going forward, this procedure is a better choice than the on-pump procedure."
Along the same lines, the cost of off-pump CABG is on the decline. The average severity-adjusted cost of an on-pump CABG procedure rose about 9% from 1999 to 2001, from $20,964 to $22,902. During the same period, severity-adjusted off-pump CABG has decreased about 3% from $23,759 to $23,031. If the trend continues, off-pump beating-heart surgery should have had lower costs, on average, compared with on-pump CABG in 2002, Foster says, although data to confirm that are still unavailable.
The study also found that the number of off-pump procedures as a proportion of all CABG surgeries has swelled in recent years with the greatest proportion--more than one-fourth of all the procedures--performed in the Northeastern U.S. On average, 22% of all bypass surgeries were performed off-pump during the study period, climbing from 15% in early 1999 to 28% in late 2001.
Foster and his team examined a total of 511,807 patients who underwent bypass surgery from Jan. 1, 1999, to Dec. 31, 2001. Patients for the study were drawn from Solucient's database derived from hospital discharge data and individual and group contracts--more than 19 million inpatient records annually, representing one out of every two discharges from U.S. hospitals each year.
"To our knowledge, this is the largest study that has been conducted to compare off-pump and on-pump (procedures) with regard to utilization of resources and mortality," Foster says.
Unplugging the heart machine
The off-pump bypass technique, a bold procedure in which surgeons dare to operate on a heart while it is still beating, has been around since 1997 when the surgical tools enabling the procedure first came on the market. Since then, use of the technique has grown to about 25% of the 800,000 CABG procedures performed worldwide each year, according to numerous studies. Use of the off-pump technique in New York state climbed from 3% of all coronary artery bypass cases in 1997 to 27% in 2000, according to Eric Rose, a cardiac surgeon and chairman of the department of surgery at Columbia University College of Physicians and Surgeons, New York.
For on-pump surgery, surgeons connect patients to the heart-lung machine, stop the heart--putting the patient into a suspended state of death--and then "bypass" blocked arteries by grafting new arteries onto the heart muscle. With off-pump, or beating-heart surgery, the procedure is performed as the heart continues to beat, eliminating in large part the need for blood transfusions. Surgeons use stabilizers and retractors designed especially for the surgery so the grafted area does not move as they operate.
On the plus side for the conventional on-pump surgery, a surgeon has better control and visualization of the heart, says Joseph Cunningham, chairman of the department of surgery at Maimonides Medical Center, New York. "The theoretical downside of doing the operation this way is that in connecting the patient to a heart-lung machine, you have introduced an external factor, and there is some evidence the heart-lung machine triggers a cascade of biological phenomena," Cunningham says.
Even surgeons who routinely perform both surgeries are conflicted about the outcomes. In a recent editorial in the New England Journal of Medicine, Rose wrote that "reliable data comparing outcomes in high-risk patients are sorely lacking. ... Until such data are available, we will not know whether off-pump bypass surgery is a step forward, backward or sideways."
Although he performs both procedures, Rose says he is reluctant to state his own decisionmaking approach. "It's still in flux because of what is appearing in the literature," Rose says. "If you asked the same question a year ago, I would have said (patients with multiple complications) ought to be done off-pump, but I'm not sure of that anymore."
Rose's editorial accompanied one of the most recent studies, published in the Jan. 30 issue of the New England Journal. The study found that everything being equal, the off-pump procedure costs $1,839 less ($14,908 vs. $13,069) than its conventional cousin. Still, the beating-heart procedure didn't seem to put patients out of harm's way any more than the more conventional open-heart surgery. The study published in the journal was conducted in the Netherlands and looked at 281 low-risk patients who underwent either single- or double-vessel bypass grafts.
Cunningham examined his own data at Maimonides and in consultation with the hospital's materials managers and perfusionists, determined there was no economic difference between on-pump and off-pump surgery. And whether it was on- or off-pump, supplies for the procedure cost more at the Brooklyn hospital than they did in the Netherlands: $2,200 per case, Cunningham says. Maimonides heart surgeons perform about 1,000 bypass operations per year; as many as 40% of those procedures are off-pump, Cunningham says, mostly depending on surgeon preference and to some extent, patient preference.
"There is no question there is a market drive to do (off-pump CABG) and a big push from the industry because they make money from the new technologies," Cunningham says. "I do think this has been used as a marketing tool by all the factors involved--industry, surgeons and institutions. That doesn't mean it's bad."
Cunningham, who has not seen the Solucient study, says, "the jury is out" about whether the procedure benefits older patients in need of four or five artery grafts. Increasingly, cardiologists performing less-invasive angioplasty procedures using stents to prop open clogged arteries--and shortly, drug-eluting stents--are cherry-picking the healthiest patients from cardiac surgeons' caseloads, not to mention a lucrative source of revenue for most hospitals (Oct. 21, 2002, p. 4).
"This technique of off-pump bypass is just another armamentarium of bypass," Cunningham says. "I don't see that many patients who are 60 years old with good ventricles who need one bypass. I would like to see (such patients) every day, but unfortunately I don't."
Despite the skepticism expressed by Rose and Cunningham, the tide has been turning in favor of off-pump bypass in recent months. In December 2002, ECRI--a Plymouth Meeting, Pa.-based not-for-profit health services research organization modeled after Consumers Union--concluded a head-to-head technology assessment that gave off-pump CABG slightly better grades than conventional surgery for reducing the risk of heart attack, stroke and wound infection, and to a lesser extent, short-term mortality. Off-pump bypass also appeared to lead to shorter hospital stays than conventional CABG, although the findings weren't conclusive for all patient subgroups.
ECRI noted that "one of the ongoing concerns about (off-pump CABG) is the learning curve associated with the procedure as it is technically more difficult to perform." But even though it has its limitations--not all patients are eligible and some areas of the heart are too difficult to reach off-pump--off-pump bypass is becoming "a significant competing technology," according to ECRI. "Continued improvement in technology and new procedural modifications will likely continue to increase the percentage of bypass procedures performed by the off-pump method."
Manufacturers of the stabilizers and retractors that make off-pump bypass possible are counting on that proportional growth. Studies indicating that the risk to patients undergoing off-pump bypass is equivalent to the risks to patients who are connected to the heart-lung bypass machine "is a good thing," says Nicky Spaulding, president of European operations for Guidant Corp., Indianapolis, a leading manufacturer of those tools. Equivalence marks just the first positive step in adoption of new technologies. And despite the inconclusive studies, Spaulding argues that the off-pump procedure already saves healthcare dollars in large part because blood transfusion costs are eliminated.
Guidant manufactures one brand of the stabilization devices used in the surgery. Sales of the single-use-only devices, which sell for about $1,500 per surgical pack, are climbing but not rapidly, "because of the education and training" associated with the newer technique, he says.
Even third-party reprocessing companies are getting into the act: Phoenix-based Alliance Medical Corp. last month announced that it had developed a technology to reprocess the chest retractors, heart positioners and tissue stabilizers that are used in off-pump procedures. Alliance estimates that it will reprocess at least 3,000 units during the first year, saving hospitals more than $2 million, or as much as $700 per off-pump CABG procedure.
Looking to the future, Guidant sees even bigger things for off-pump surgery--"a transformation in the field that will be better," Spaulding says. Taking patients off the heart-lung machine is just the first step in a procedure that promises to become less invasive over time. Guidant's newest product offers the opportunity to perform clampless, beating-heart surgery, reducing the trauma and the risk of extraneous debris making its way to the brain, he says. After that, Guidant will move on to the goal of getting the surgeon's hands out of the chest, eliminating the need for across-the-chest incisions and further reducing the risk of complications.
"We think anytime you can cause less infection (and) less morbidity, that will translate into less cost," Spaulding says.
Indeed, regardless of whether it's performed on- or off-pump, the CABG market is stagnant right now, says Amit Bohora, a research analyst for Frost & Sullivan, a San Jose, Calif.-based healthcare growth consulting firm. Yet minimally invasive CABG, a tiny portion of the overall market that accounts for less than 10% of all procedures, is growing by nearly 7% a year, he says.
Similarly, technologies associated with off-pump bypass surgery are one of the faster growing product lines at Medtronic, Minneapolis, says Robert Hanvik, a company spokesman. Medtronic's flagship product, a heart positioner and stabilizer, was used in the Netherlands study published in the New England Journal.
"I would argue in a lot of ways (off-pump surgery) has become the standard of care," Hanvik says.
Contrary to those who say drug-eluting stents will eventually erode the volume of lucrative bypass surgeries performed in hospitals, significantly decreasing revenues, Medtronic believes off-pump bypass surgery eventually will give angioplasty a run for its money.
"There are a lot of learning curves in these studies, and one thing we have discovered is that when surgeons first start doing (off-pump bypass) they say it's harder, it takes longer and it's more expensive," says Jodi Harpstead, vice president and general manager of cardiac surgery technologies for Medtronic. "But as surgeons commit and get good and do it, they say it is clearly easier, faster and cheaper."
Like Spaulding, Harpstead says, "we intend to march further down that path to minimally invasive beating-heart surgery." Within the next couple of months, she says, Medtronic will launch a product that will enable heart surgeons to perform beating-heart surgery with a much smaller, bone-sparing incision. By the end of 2003, she adds, other companies will have technologies that allow physicians to perform "totally endoscopic CABG," she says.
Harpstead makes a bold prediction: Within a year, the industry will be able to provide hospitals with the technology to perform minimally invasive triple-bypass surgery at half the cost of performing angioplasty in three vessels using the much-touted drug-eluting stents. The debate, she says, will focus on which of the procedures is more invasive. Riding in bypass surgery's favor is the expected lifespan of a bypass graft staying open--10 to 20 years.
"No stent has ever been able to get close to that," Harpstead says.
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