An innovative technique in heart coronary bypass surgery developed at the Bristol Heart Institute significantly reduces the risk of postoperative morbidity, time in intensive care and length of hospital stay. Known as off-pump beating heart coronary surgery (OPCAB), the technique is increasingly popular worldwide and is used in 15-20% of coronary artery bypass grafting surgery. The technique is as safe as conventional surgery, and is a key example of the groundbreaking research that has made the Bristol Heart Institute, part of the University of Bristol, internationally famous for its pioneering developments in the field of cardiac surgery.
The cardiovascular killer
Cardiovascular disease is the UK’s biggest killer, accounting for almost half of all deaths and killing more people each year than all types of cancer combined. The term ‘cardiovascular disease’ encompasses all disorders of the heart and circulatory system. The most common problem is coronary heart disease, which results from the furring-up of the arteries that supply the heart with blood. At the Bristol Heart Institute, researchers are investigating ways to improve the quality of grafts used in surgery to bypass blocked arteries, which includes the design and use of solutions that protect the heart during operations.
The conventional approach
During surgery, the heart is normally paralysed by a cardioplegic solution, while blood is diverted from the vascular system and pumped through plastic tubing outside the body. This artificial pump temporarily performs the functions of the heart and lungs during surgery, so circulation of the blood continues, ensuring that body tissues, particularly those of brain and other vital organs, remain alive. This type of surgery is known as ‘on-pump’ surgery. For many years, on-pump surgery has represented the gold standard in restoring coronary blood vessel function – during vein-graft operations, for example, where a piece of leg vein is used to bypass a blocked artery in the heart.
Compared with 20 years ago, patients undergoing ‘on-pump’ bypass surgery today are at higher risk of serious complications because they are older, have greater severity of coronary heart disease, more risk factors, and more frequently require urgent or emergency procedures. On-pump surgery in these high-risk groups may be associated with high complication rates, substantially increased death rates and increased costs.
In 1995 a new technique - beating heart surgery - was pioneered at the Bristol Heart Institute. The technique required the development of a special stabiliser to keep a small part of the heart still so that the surgeon could operate on that part while the rest of the heart kept beating. This is also known as ‘off-pump’ surgery, since there is no need for the artificial pump.
Clinical trials carried out at the Bristol Heart Institute confirmed that short-term benefits to patients were much better if the heart did not have to stop beating – there were fewer post-surgery complications, such as infections due to inadequate clearance of fluid from the lungs and temporary kidney failure. There was also less blood loss and transfusion requirement, and reduced damage to the heart muscle itself.
Results that improve lives and reduce costs
Independent studies confirm that off-pump surgery significantly reduces the risk of post-operative morbidity, time in intensive care and length of hospital stay – and has resulted in a 25% cost saving per patient treated. Currently, 15-20% of coronary artery bypass grafting operations are carried out with the ‘off-pump’ technique worldwide. The figure for the UK is 17%. In obese patients, off-pump surgery has proved even more beneficial, and has resulted in reduced in-hospital mortality and neurological injury.
From an innovation to an increasingly adopted standard
Since 1995, the usage of the OPCAB technique has gone from less than 2% to 15-20% worldwide, and the proportion is expected to rise in the next few years. Off-pump surgery is now routine practice for five out of the seven consultant cardiac surgeons at the Bristol Heart Institute, and makes up more than 95% of their coronary surgical practice. The total number of off-pump cases at the BHI has risen from 25-30 cases a year in 1995 to more than 750 cases a year in 2008, with over 7000 cases in total. Since 1995, more than 10 trainees have been taught the OPCAB technique in Bristol and have subsequently taken up consultant jobs in the UK, or worldwide, resulting in the global spread of the technique. Once surgeons are trained and accustomed to OPCAB, they are reluctant to go back to on-pump surgery because they are more comfortable with the OPCAB technique which reduces the use of resources and lowers early postoperative morbidity.
The research at the Bristol Heart Institute has been recognised by independent external sources with the following awards:
- ‘Surgical Team of Year’ Award by Hospital Doctor in 2005
- ‘Cardiovascular Team of Year-runner up’ Award by Hospital Doctor in 2005
- ‘John Parker Gold Medal’ by UK Society of Cardio-thoracic Surgery in 2001
Continued monitoring of early and long-term outcome for patients, including in-hospital outcome, survival rates and quality of life, and the provision of training for cardiac surgeons in off-pump techniques are now underway to determine whether off-pump surgery performed on the beating heart will supersede conventional surgery.