Heart bypass surgery rates fall by 38% between 2001 and 2008: Study

By Dr. Ananya Mandal, MDMay 4 2011

According to latest the U.S. research, the number of heart patients getting bypass surgery fell by 38 percent between 2001 and 2008. This fall reflects several factors, including a decline in smoking rates, which has led to less coronary artery disease, said senior study author Dr. Peter Groeneveld, an assistant professor of medicine at the University of Pennsylvania School of Medicine.

Other factors include better and more aggressive treatment of coronary artery disease risk factors, such as high blood pressure, high cholesterol and diabetes, means fewer patients progress to needing surgery. Researchers add that another factor is that many patients with blocked arteries instead undergo percutaneous coronary intervention (PCI), also called balloon angioplasty, in which a doctor threads a catheter into the artery and inflates a balloon at the tip. Usually, a wire mesh structure called a stent is left behind to prevent the artery from narrowing again.

Though PCI is an excellent option for many patients, researchers stressed that bypass surgery may be the best option for some patients with certain severe blockages, including those with triple blockages or left main coronary artery stenosis, Groeneveld said. “Patients need to be aware that CABG can be a good treatment option, and it's gotten better…There have been several innovations that have made the recovery time much less than it used to be,” he said. In CABG, a new artery or vein is grafted, or connected, to the blocked artery to restore blood flow. The study is published in the May 4 issue of the Journal of the American Medical Association.

For the study the team analyzed data on a national sample of patients who underwent procedures to clear blockages at U.S. hospitals between 2001 and 2008. Most of the procedures were scheduled, though some were for emergency situations such as heart attacks. During that period, there was a 15 percent overall decrease in procedures to clear coronary blockages, the investigators found. Most of that reduction was because of a decline in annual bypass surgeries, which dropped by 38 percent. PCI, in contrast, held mostly steady with a 4 percent dip.

Researchers then translated the figures to the entire U.S. population and found that there were an estimated 130,000 fewer bypass surgeries in 2008 compared with 2001.

Dr. Debabrata Mukherjee, chief of cardiology at Texas Tech University Health Sciences Center, said even though PCI popularity has risen (the number of hospitals offering PCI increased by 26 percent during the study period, compared to about 12 percent for bypass), technological advances have made fewer PCI surgeries necessary.

He explained that earlier about one-third of PCI patients needed a re-do within six months. Now after 2003, the U.S. Food and Drug Administration approved drug-eluting stents, which come with an immunosuppressant coating that helps prevent scarring and inflammation around the stent. These prevent the need for a re do he explained. “Now, 5 percent, maybe 10 percent at most, need to come back,” he said. “There has been a marked decrease in repeat procedures. So even as cardiologists are taking on more complex, multi-vessel cases, the overall volume of PCI hasn't gone up.”

Groeneveld raised another possibility for the decline in bypass surgery. He said interventional cardiologists can do PCI, while only cardiac surgeons do bypass surgery. Since most people see a cardiologist who would refer them to a cardiac surgeon if necessary, it's possible some patients who might be better off getting bypass surgery are being offered PCI instead, Groeneveld said. “My hunch is cardiologists are referring fewer [patients] onto surgeons and treating more with interventional cardiology,” he said. “The worry is there are patients who really who should be getting CABG that aren't getting it.”

In 2009, a U.S.-European team compared stenting and bypass surgery in severe cases and reported in the New England Journal of Medicine that 13.5 percent of stented patients needed surgery for another blockage within a year. Only 5.9 percent of those getting coronary bypass surgery did. But another look at the same patients, in the March 17 New England Journal of Medicine, found that percentages of the patients free of chest pain at 6 and 12 months post-procedure were practically the same in the bypass and stent groups — 72 to 76 percent.