The death rate during combination surgery to bypass clogged coronary arteries and simultaneously replace a heart valve in very sick patients can be as high as one in five, but a review of records of very sick patients who underwent balloon angioplasty, followed by heart valve replacement surgery, found only one death among 26 patients, according to a new study in the Jan. 4, 2005 issue of the Journal of the American College of Cardiology.
“This is one of the futures of cardiovascular interventions,” said John G. Byrne, M.D. “Our intuition was that it would be better, but we were surprised it was that much better. There was a predicted operative risk of 22 percent with the valve and bypass surgery, and we dropped that down to about 4 percent with the staged approach of angioplasty followed by valve replacement surgery.” With the aging of the population, more and more patients may present with disease of both the heart valves and coronary arteries, increasing the impact of these differing percentages.
Dr. Byrne performed the study with colleagues at Brigham and Women’s Hospital in Boston. He is now at Vanderbilt University Medical Center in Nashville.
The study involved a retrospective review of the medical records of 26 consecutive patients who underwent angioplasty followed by valve surgery from September 1997 to August 2003. The decision to use the two-stage “hybrid” approach was made by each patient’s cardiologist and surgeon. There was no control group in the study.
The patients were very sick. Many had diabetes, lung disease, kidney failure or other health problems. Close to a third of them were on a ventilator, and more than 40 percent had just suffered a heart attack. Based on their clinical characteristics, the researchers predicted it was likely that more than one out of five would have died during conventional combination bypass and valve replacement surgery.
“However the study involved small numbers. If we had had one more death in the study group, the operative risk would have been 8 percent, instead of 4 percent; so the results must be kept in perspective, recognizing the small number of patients,” Dr. Byrne said.
Survival at one, three, and five years was 78 percent, 56 percent, and 44 percent, respectively. According to Dr. Byrne, these long-term survival rates are similar to those following conventional bypass and valve surgery. The patients in the study did suffer more bleeding and needed more transfusions than would have been expected with conventional surgery. Dr. Byrne pointed out that almost all of the patients were given stents to hold their coronary arteries open. He said that medication with clopidogrel (Plavix ®) to reduce the risk of blood clots forming in the stents probably contributed to increased bleeding during the valve surgery.
Dr. Byrne also emphasized that the patients in this study were far sicker than most patients who undergo bypass and valve surgery. Because the death rates would be very low for either technique among more typical patients, Dr. Byrne said he wouldn’t expect to see dramatically different death rates between the two groups. Nevertheless, he predicted further study might demonstrate better outcomes in terms of hospital stays and costs, pain and suffering.
“As angioplasty and stenting become better and better, I think we’ll be seeing more of these hybrid procedures in groups of patients that are not as high-risk, in moderate-risk groups and even in low-risk groups,” Dr. Byrne said.
At the time of the study, patients underwent angioplasty in cardiac catheterization laboratories; and then a few days later they underwent valve replacement surgery in an operating room. Some hospitals are already building hybrid procedure suites in order to do both procedures without having to wait or move the patient.
David S. Bach, M.D., at the University of Michigan in Ann Arbor, who was not connected with this study, noted that it was a retrospective look at only a small number of unusually sick patients.
“As a result, the estimated risk for combined surgery in this study was very high, which would have tended to exaggerate the benefit of the hybrid approach,” Dr. Bach said.
Nevertheless, he said the results suggest the hybrid approach is an attractive option for certain patients. He said it is already being applied more broadly.
“By extension, a similar staged approach may be reasonable in other, less high-risk, cases. At the University of Michigan, we employ such a staged approach for some patients in a non-emergent setting,” he said.