Men and women are different, and anyone who doubts it should ask a heart surgeon. For years, cardiac surgeons and researchers have been puzzling over the differences between men and women related to coronary bypass surgery.

Coronary artery bypass graft (CABG, pronounced “cabbage”) has been the gold standard for the treatment of coronary artery disease for 30 years. In fact, it’s the possibly the most common surgery performed in the United States - upwards of half a million procedures a year, according to the American College of Cardiology.

Of that total, about one third are women, more than 150,000 a year. As awareness of women’s heart disease has expanded and more women are referred for surgical treatment, some obvious differences in outcomes between men and women have attracted considerable attention.

The changing picture
Much of the research on gender differences related to CABG was conducted in the 1990s, and the answers were somewhat disconcerting. Study after study demonstrated that women had a 1.5- to 2-times higher in-hospital mortality rate after CABG than men. The most accepted theory for this difference is that women having the operation are higher-risk patients than men. They tend to be older, have a smaller body size and smaller coronary arteries, more co-morbidity (other conditions such as diabetes, kidney disease and high blood pressure) and more advanced disease than do their male counterparts.

A more recent study of 2,200 patients who underwent CABG at Cleveland Clinic between 1993 and 2003 offers more encouraging news for women. In this study, investigators did not find a gender difference for in-hospital mortality. They did determine that women still have a longer length of stay after CABG and higher postoperative complication rates – and these factors may affect a woman’s recovery from cardiac bypass surgery after she leaves the hospital.

Another study, conducted by several leading New England hospitals, likewise found that the situation is improving for women. When researchers compared patients and outcomes from 1987 to 1989 with those from 1993 to 1997, they found that although women having CABG in the latter group actually were older and sicker than earlier patients, the mortality rate had decreased.

Newer options for high-risk patients
Clearly, progress is being made to improve results for women who undergo CABG. Meanwhile other, newer surgical techniques for cardiac bypass surgery are now available that may offer some women potentially better outcomes.

Bruce Lytle, M.D., Chairman of the Cleveland Clinic Department of Thoracic and Cardiovascular Surgery, and cardiovascular surgeon Joseph Sabik, M.D., were among the first physicians to suggest that the era of “one size fits all” cardiac revascularization surgery is over. In a paper they published in 2004 in Circulation, the official journal of the American Heart Association, they suggested that conventional CABG is still the procedure of choice for some patients but other, “off-pump” techniques may be better for certain high-risk patients. These leading-edge techniques accomplish the same objectives as CABG in restoring coronary blood flow, but they are shaping up to be safer for some patients - including women.

In CABG, the operation is performed after the heart is stopped and the patient is placed on the heart-lung machine. Officially known as cardiopulmonary bypass, the heart-lung machine performs the function of the heart and lungs external to the body, allowing the surgeon to manipulate a heart that is not in motion.
The newest surgical techniques include OPCAB – off-pump coronary artery bypass- which allows the surgeon to perform a bypass procedure without requiring the heart-lung machine. The patient's heart continues beating while the surgeon uses a device to stabilize the portion of the heart where the cardiac bypass surgery will be performed.

OPCAB appears to be a safe, effective alternative to CABG for high-risk patients, including women, who have more than one vessel requiring bypass. For patients who require only single-vessel bypass, minimally invasive direct coronary artery bypass (MIDCAB) can be performed on the beating heart through a three- to four-inch chest incision.

A study published in Circulation in 2002 specifically compared outcomes for CABG and OPCAB in more than 21,000 women. Women who had off-pump cardiac surgery fared far better than those who had conventional CABG. Mortality and complication rates were lower by a large margin, and off-pump patients had a shorter hospital stay and were more likely to be discharged directly to home than were those who had CABG using the heart-lung machine.

Getting good advice
What does all of this mean in practical terms if you are a woman who needs coronary bypass surgery? Locate an institution that offers all of the surgical options and find a cardiologist and surgeon there who is experienced in treating women. He or she will be best equipped to evaluate your personal health and risk factors and determine the best treatment for you.

For questions or more information call the Cleveland Clinic Heart Center Resource and Information Center Nurse at 216/445-9288 or toll-free 866/289-6911. For an appointment with a Cleveland Clinic women’s heart specialist, call toll-free 800/223-1696 or locally, 216/444-9343. Or, you may use the Contact Us form to contact us by email.

Learn more about coronary artery bypass surgery.

References

• Blankstein R, Ward R., Arnsdorf M et al. Female Gender is an Independent Predictor of Operative Mortality after Coronary Artery Bypass Graft Surgery. Circulation. 2005;112:I-323-7.
• Brown P, Mack M. Outcomes experience with off-pump coronary artery bypass surgery in women. Ann Thorac Surg. 2002;74:2113-20.
• Christakis G, Weisel R, Buth K et al. Is body size the cause for poor outcomes of coronary artery bypass operations in women? J Thorac Cardiovasc Surg. 1995;110: 1344–1358.
• Edwards FH, Carey JS, Grover FL t al. Impact of gender on coronary bypass operative mortality. Ann Thorac Surg. 1998;66:125–131.
• Edwards ML, Albert NM, Wang C, Apperson-Hansen C. 1993- 2003 gender differences in coronary artery revascularization: has anything changed? J Cardiovasc Nurs. 2005;20(6):461-7.
• Guru V, Fremes SE, Austin PC, Blackstone EH, Tu JV. Gender differences in outcomes after hospital discharge from coronary artery bypass grafting. Circulation. 2006;113(4):507-16.
• Koch CG, Mangano CM, Schwann N et al. Is it gender, methodology, or something else? J Thorac and Cardiovasc Surg. 2003;126 (4):932–935.
• O’Rourke DJ, Malenka DJ, Olmstead EM et al. for the Northern New England Cardiovascular Disease Study Group. Improved in-hospital mortality in women undergoing coronary artery bypass grafting. Ann Thorac Surg. 2001;71:507–511.
• Lytle B, Sabik J. On-pump and off-pump bypass surgery: Tools for revascularization. Circulation. 2004;109:810-812.
• Patel S, Smith JM, Engel AM. Gender differences in outcomes after off-pump coronary artery bypass graft surgery. Am Surg. 2006;72(4):310-3.

Websites for more information:

• American Heart Association website.
  Heart Healthy Women website.
  CTSNet website

Reviewed by Dr. Cho and Dr. Sabik