On-Pump Bypass & Off-Pump Have Similar Outcomes After 1 YearMain Category: Cardiovascular / Cardiology
Also Included In: Heart Disease | Medical Practice Management
Article Date: 12 Mar 2013
Patients who undergo heart bypass surgery without a heart-lung machine do just as well after one year as those whose hearts were connected to a pump during the procedure.
The finding came from a new study presented at the American College of Cardiology's 62nd Annual Scientific Session.
CORONARY is a global, multi center trial comparing on-pump (with a heart-lung machine) to off-pump bypass surgery.
The study, the largest yet to compare the two methods, consisted of 4,752 patients who were about to undergo a bypass procedure.
The experts found no notable difference between patients receiving the off-pump and on-pump procedures for the primary endpoint of their composite outcomes of stroke, death, heart attack or new kidney failure needing dialysis within one year after surgery (12.2 vs. 13.3 percent, p = 0.24.).
This primary endpoint was observed previously in a study for patients at one month, which also found the two procedures to be statistically similar in the short-term.
However, contradictory results from other trials raised questions about patients' intermediate (one year after surgery) and long-term outcomes.
Andre Lamy, MD, lead author of the CORONARY study and professor in the division of cardiac surgery at McMaster University in Ontario, Canada, said:
"We found that both on-pump and off-pump bypass have similar results, even at one year. Both surgical approaches are effective when provided by experienced surgeons."
In the U.S. and the rest of the world, coronary artery bypass graft surgery (CABG) is among the most commonly performed procedures. More resources are consumed in cardiovascular medicine in this operation than any other procedure.
During the on-pump CABG, the person's heart stops and blood is circulated through a heart-lung machine, where it is supplied with oxygen and returned to the patient.
During the off-pump method, the doctor uses a retractor to raise the heart, which is still beating, and performs all coronary artery grafts.
In this procedure surgeons do not have to insert a tube, known as cannula, into the aorta, cross-clamp the aorta, attach the patient to the heart-lung machine and stop and restart the heart.
The CORONARY trial involved patients from 79 centers in 19 countries who were about to undergo CABG. The subjects were randomly assigned to undergo on-pump or off-pump CABG after an evaluation to make sure they were suitable for both methods.
Other than the primary endpoint, the experts also focused on how many patients required coronary revascularization in the two groups
The researchers said:
"This entails restoring blood flow to the heart through a repeat CABG or placement of a stent and indicates the initial CABG procedure was not successful. Again, results were similar between groups with 1.4 percent of patients in the off-pump group and 0.8 percent of patients in the on-pump group requiring this additional procedure."
By using standardized scales, the report also evaluated the neurocognitive function and quality of life of the participants in both groups.
"We found a transient improvement in neurocognitive function at hospital discharge among those receiving an off-pump bypass," Dr. Lamy said. "But at one year, our results are similar with both techniques."
The scientists were surprised to see this transient difference in patients' neurocognitive functions, since smaller trials have found proof of short-term neurocognitive declines among people undergoing both bypass procedures.
Patients' quality of life were comparable after both on- and off-pump bypass.
The results from this study are different from those appearing from a different large trial that indicated outcomes one year after on-pump surgery. This difference is probably associated with the surgeons' expertise in the two methods, as well as the surgical risk of each subject, Dr. Lamy pointed out.
"Compared to the other trial, our patients were older and sicker, and our surgeons were more experienced, particularly in performing off-pump bypass," Dr. Lamy said. A higher degree of surgical skills are needed for off-pump bypass, because the surgery takes place while the patient's heart is still beating.
Therefore, surgical expertise is a main factor impacting patient outcomes, and according to Dr. Lamy, it is possible that other trials have not controlled for this.
All of the doctors who took part in the study needed to have performed at least 100 cases in the method used, although most of the surgeons had a lot of experience with both types of methods.
Dr. Lamy said:
"The CORONARY study shows that off-pump bypass is just as good as on-pump. Therefore, surgeons should tailor their surgical approach to their technical expertise and expected technical difficulty."
The patients in the CORONARY study will be monitored for five years. This continued assessment will hopefully provide required proof about the effectiveness of on- and off-pump bypass after the first year.
Written by Sarah Glynn
Copyright: MediLexicon International Ltd
Original article posted on Medical News Today.
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