August 25, 2010
Clinical Trial Findings Challenge Clinical Practice
First randomized controlled trial demonstrates patients do not benefit from routine balloon pumping during high-risk angioplasty
Patients with coronary artery disease undergoing angioplasty do not benefit from having their circulation artificially supported with a balloon pump as a preventative measure during angioplasty, according to the first randomised trial studying the practice and published today in the Journal of the American Medical Association (JAMA).The trial was carried out across 17 tertiary referral cardiac centres in the UK and was designed and led by Dr Divaka Perera and Dr Simon Redwood, interventional cardiologists at Guy's and St Thomas' Foundation Trust in London1. The study was funded by unrestricted educational grants and the principal investigators were supported by the atherosclerosis theme of the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre at Guy's and St Thomas' and King's College London.
Angioplasty is a common procedure performed under local anaesthetic to open up the narrowed sections of a patient's arteries. A small balloon is inflated within the narrowed artery to open the blockage, and a metal scaffold (stent) is inserted to keep the artery open. Patients with poor heart function and extensively narrowed heart arteries are at higher risk of complications following angioplasty and there has been much interest in the balloon pump as a means of reducing such adverse events. When a balloon pump is used, it is placed inside the patient's aorta (the main artery supplying blood to the body) to provide circulatory support to their failing hearts. Over the last 20 years, cardiologists across the world have adopted use of the balloon pump as a preventative measure during high risk angioplasty, but this common practice has been based on anecdotal accounts and small observational studies, which are limited by selection bias.
The Balloon pump assisted Coronary Intervention Study (BCIS-1) involved 301 patients with severe left ventricular dysfunction and extensive coronary artery disease. They were randomly assigned to either have the balloon pump inserted before angioplasty or to have angioplasty without planned balloon pump support.
There was no difference in the proportion of patients who suffered major cardiovascular complications (comprising death, acute myocardial infarction, cerebrovascular events or further revascularisation, at hospital discharge capped at 28 days) in the group who received a balloon pump beforehand (15.2%), compared to those who did not (16%). However, approximately one in eight of the latter group required an emergency balloon pump insertion during the procedure, emphasising the importance of having a balloon pump on standby when undertaking such cases2.
Dr Simon Redwood, Reader in Interventional Cardiology at King's College London and Honorary Consultant Cardiologist at Guy's and St Thomas' said: "For many years we have strongly advocated the use of the balloon pump to support patients' circulatory system during high risk coronary angioplasty and wanted to build up definitive evidence to support its use. We believed this multi-centre study would establish once and for all the clinical and safety benefits of using the pump as a preventative measure.
"However, rather than demonstrating the benefits, we found that inserting a balloon pump into the aorta as a preventative measure has little or no impact on the incidence of major complications and death in high risk cardiac patients, although there is still an important role for using a pump in an emergency.
"Angioplasty is now the most common interventional treatment for treating coronary artery disease. The study findings raise important questions about current clinical practice and whether it is necessary to use a balloon pump routinely during the procedure. The findings may reflect the fact that angioplasty has become a less risky procedure over time as cardiologists have increased their skills."
Dr Martyn Thomas, lead of the cardiovascular clinical academic group at King's Health Partners Academic Health Science Centre, which includes Guy's and St Thomas', King's College London and the NIHR Biomedical Research Centre said: "It is vitally important that high quality research underpins clinical practice, and studies such as this are key to informing cardiac practice nationally and internationally."
The cardiac units at Guy's and St Thomas' and King's College Hospital NHS Foundation Trusts, the two acute Trusts within King's Health Partners, jointly perform approximately 3000 interventional cardiology procedures a year, and form one of the biggest cardiac centres in the UK.
On the Net: