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New initiative helps Emergency Department reduce number of CT scans

Toronto, March 4, 2016

By Corinne Ton That

Dr. Samuel Vaillancourt
Dr. Samuel Vaillancourt, an Emergency Department physician, led an initiative to help doctors reduce the number of CT scans when assessing patients with symptoms of pulmonary embolism. (Photo by Yuri Markarov)

A new initiative at St. Michael’s Hospital is helping doctors and clinicians in the Emergency Department reduce the number of CT scans when assessing patients with symptoms of pulmonary embolism – a blood clot in the lung.

The initiative will help doctors and clinicians decide on the best test to use when assessing those patients, using new guidelines that helps them determine whether patients are at a low, moderate or high risk of having a pulmonary embolism.

If a patient is deemed to be at a low or moderate risk, doctors can order a D-dimer blood test rather than a CT scan as an initial test. D-dimer tests are used to rule out the presence of blood clots by measuring a protein fragment in the blood, which is released when blood clots break up. If patients are at a high risk, they should undergo a CT scan immediately.

A pulmonary embolism can be life-threatening and occurs when a blood clot in the leg breaks loose and travels to the lungs. Symptoms include shortness of breath, a rapid heartbeat and coughing up blood.

“There’s been a rapid increase in the use of CT scans for testing people with pulmonary embolism symptoms and this subjects patients to potentially harmful radiation,” said Dr. Samuel Vaillancourt, an ED doctor who led the initiative. “We’re trying to safely decrease the risk of radiation from CT scans by optimizing the use of the D-dimer test.”

   
Did you know?
  • D-Dimer blood tests are used to rule out the presence of blood clots
  • The test can deliver results in less than one hour
  • The test can be used for patients with low or moderate risk of pulmonary embolism

The Department of Laboratory Medicine has devoted more resources to ensure D-dimer test results are available within an hour. If the test results are negative, patients don’t need to go onto further testing and imaging, said Dr. Kieran McIntyre, who also worked on the initiative.

“We’ve shown that if the D-dimer test is negative in patients with low to moderate risk of pulmonary embolism, then they don’t need to have further testing like CT scans– we know the D-dimer can safely rule out blood clots,” said Dr. McIntyre.

Between two and three patients are assessed for pulmonary embolism in the ED at St. Michael’s every day and there is “good evidence that a lot of people in North America are getting avoidable CT scans,” said Dr. Vaillancourt.

“Research shows that up to 32 per cent of people at low or moderate risk of pulmonary embolism undergo potentially avoidable imaging,” he said.

The initiative, launched at St. Michael’s in September, is part of the Choosing Wisely Canada campaign, which encourages doctors and patients to find ways to reduce the number of unnecessary tests, treatments and procedures.

About St. Michael's Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael's Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.