Steroids used in heart surgery harm patients, McMaster study finds
McMaster University doctor leads international study on the effects of steroids in bypass surgery
In Canada, close to 25,000 patients receive heart bypass surgery every year and about one-third of those patients are given steroids to reduce inflammation as a result of the surgery.
A new study conducted on an international scale is now presenting evidence that the use of steroids, commonly methylprednisolone, carries no benefits and in fact causes harm to some patients.
''There was more heart injury [with the use of steroids] which means the patients had a worse outcome. We have to find out why it’s doing this.' - Dr. Richard Whitlock, cardiology at McMaster University
“All research is important because it tells us what to do and what not to do in treating patients. There was more heart injury [with the use of steroids] which means the patients had a worse outcome,” Dr. RichardWhitlock, associate professor of cardiac surgery at McMaster University, and lead investigator of the study, told CBC Hamilton.
“We have to find out why it’s doing this.”
The inflammation is a reaction to Cardiopulmonary bypass, or the “heart-lung machine”, a technology that ensures blood continues to flow into the lungs and around the body while the heart is stopped during surgery. Tubes are connected to the heart to take blood from the heart, oxygenate it, and circulate it around the body. According to Whitlock, the body senses an exposure to foreign substances like the plastic tubing and oxygenator and as a result release bacteria-fighting chemicals in huge amounts into the blood stream.
This sets off an inflammatory protest that affects various part of the body. Patients may experience several symptoms like low blood pressure, bleeding from the surgical site because the blood is not clotting, kidney injury or liver injury.
In Canada, about 30 per cent of heart surgery patients receive steroids
Steroids are known to suppress inflammation and so since the 1950s it has been common practice in many cardiac centres around the world to use steroids, according to Whitlock. In Canada, about 30 per cent of patients receive steroids; while in many parts of Europe, such as the Netherlands, nearly all patients are given steroids.
The study involved more than 7,500 patients who underwent cardiac surgery with the use of the heart-lung machine from 18 countries spanning North America, South America, Europe, the Middle East and Asia. Half the patients were randomly assigned to receive methylprednisolone, a common steroid used to prevent inflammation, and half received a placebo.
The researchers assessed the patients 30 days after surgery. They found that use of steroids did not show a significant benefit over placebo use in terms of the overall rate of death or post-operations complications including heart attack, stroke, renal failure or respiratory failure.
If the use of steroids did not show any significant benefit, did it pose further risk to heart patients? The study says yes. Patients who received methylprednisolone faced a 15 per cent greater risk of death or heart attack and a 21 percent greater risk of heart attack alone. Of the study’s 7,500 participants, 927 had a heart attack and 332 died.
“Based on these results, we suggest that steroids should not be used prophylactically during cardiac surgeries that require the use of cardiopulmonary bypass,” said Dr. Richard Whitlock,
Whitlock says because of funding from the Canadian Institute of Health Research, the research now provides an answer to an issue that many surgeons did not know the answer to. This research will not only help Canadians, but globally, almost 2 million people who undergo this surgery every year.