Heart beating coronary artery bypass (bypass surgery) compared to the classic coronary artery bypass surgery: better direct benefits – greater long-term risks and need for new reperfusion, as has been shown by a large-scale research of a cardiac surgery center in Beijing, which has been published in Circulation. (Short-term benefits of off-pump bypass surgery off-set by long-term risks in Beijing study, Circulation 2010)
A large-scale study raises doubts about the duration of the benefits of the beating heart coronary artery bypass surgery (“off-pump” coronary artery bypass - OPCAB) as alternative to the cardiopulmonary bypass surgery1. In a study of 6665 patients, with Dr Shengshou Hu being in charge (Chinese Academy of Medical Sciences, Beijing, China), the patients that were treated with the OPCAB procedure had less direct complications compared to the patients that have undergone cardiopulmonary bypass, but the incomplete revascularization was more common in the “off-pump” technique, leading to more vascular complications and repeated revascularizations. The results of the study were published on the Internet on April 12, 2010 in the medical journal Circulation. In the study, 3266 patients that were treated with the OPCAB method at Fuwai Hospital in Beijing between 1999 and 2006 had lower rates of intra-hospital atrial fibrillation, needed less blood transfusions and spent less time in mechanical ventilation compared to the 3399 patients that have been treated with the conventional coronary artery bypass surgery at the same time period.
Both groups had similar survival rates, however, after an average monitoring period of 4.5 years, the rates of repeated revascularization and major vascular events where significantly higher in the group that was treated with the OPCAB method compared to the respective rates of the group that was treated with the conventional coronary artery bypass (conventional bypass).
The rates of inpatient mortality and of other adverse reactions are favorable compared to the reported rates in the USA or the Western European populations, according to the authors. Intra-hospital adverse effects and adjusted relative risk of OBCAB compared to CABG
| Adverse effects | OBCAB (n=3266), n | CABG (n=3399), n | Adjusted OR (95% CI) | p |
| Deaths | 32 | 52 | 0.74 (0.46-1.18) | 0.21 |
| Cerebral infarction | 9 | 25 | 0.46 (0.21-1.02) | 0.06 |
| Myocardial infarction | 6 | 10 | 0.71 (0.26-1.96) | 0.51 |
| Atrial fibrillation | 267 | 331 | 0.80 (0.66-0.97) | 0.02 |
| Blood transfusion | 2139 | 2438 | 0.85 (0.73-0.97) | 0.03 |
| Reoperation due to bleeding | 37 | 49 | 0.88 (0.55-1.41) | 0.60 |
| Prolonged ventilation (>24h) | 120 | 256 | 0.62 (0.49-0.78) | <0.001 |
An analysis with a similar trend in the results with 2088 OPCAB patients and 2088 CABG patients did not show any differences in the risk of death from all causes, but showed a higher rate by 19% of the critical vascular events, which is a statistically significant rate and a higher rate by 38% of the repeated revascularizations in the group that was treated with the OPCAB method compared to the group of patients that have been treated with the conventional coronary artery bypass surgery (conventional-CABG). As it is reported, in 2203 patients, the randomized On/Off Bypass (ROOBY) study that has been performed in 18 centers did not show any difference in the neuropsychological effects between the coronary artery bypass with extracorporeal blood circulation and without extracorporeal blood circulation within a period of 1 year. Dr. Shengshou Hu and others point out that most of the randomized trials that compare the coronary artery bypass with and without the use of an extracorporeal blood circulation pump were small, with relatively short-time monitoring, but after an analysis of 37 randomized trials out of a total of approximately 3500 CABG patients, a negligible reduction has been observed in the inpatient mortality between the OPCAB patients2. “There is the need of a significantly larger volume of randomized data so that there can be a reliable comparison between the results of processes without an extracorporeal blood circulation pump and the ones of the conventional procedures.” As it has been found out in ROOBY, the study of Dr Shengshou Hu showed a strong correlation between the OBCAB surgery and the incomplete revascularization. “This finding provides further supporting evidence regarding the concerns for incomplete revascularization that is related to the beating heart technique. “There is strong evidence that the incomplete revascularization in CABG can lead to poor long-term prognosis.”
References
1. Hu S, Zheng Z, Yuan X, et al. Increasing long-term major vascular events and resource consumption in patients receiving off-pump coronary artery bypass. A single-center prospective observational study.Circulation 2010; 121:1800-1808.
2. Wijeysundera D, Beattie WS, Djaiani G, et al. Off-pump coronary artery surgery for reducing mortality and morbidity: meta-analysis of randomized and observational studies. J Am Coll Cardiol 2005; 46:872-882.