A little-known and life-threatening condition is showing up increasingly often in Canadian patients, according to a doctor who studied the condition's prevalence in Ontario.

Aortic dissection occurs when the aorta the main blood vessel in the chest is torn open.

Dr. Maral Ouzounian, a cardiac surgeon at Toronto General Hospital, describes the dissection as "the great masquerader" because of its similarity to other cardiac emergencies.

"We often see them being misdiagnosed as a heart attack or a stroke," she said.

Many people who suffer aortic dissections are sent home from hospital and then return complaining that their pain has not stopped, Ouzounian said.

Symptoms of an aortic dissection can include:

  • sudden onset of severe chest pain
  • pain radiating to the back, neck arms or jaw
  • dizziness
  • vomiting
  • difficulty walking and speaking

Shelly Johnson nearly suffered that fate earlier this year. When the 51-year-old Ontario nurse developed a sharp pain in her chest, her first thought was that it must be a heart attack.

"It felt like an elephant was sitting on my chest, just like other people would describe a heart attack," she said.

Johnson underwent blood tests, an X-ray and an ECG, none of which showed any issues. The doctor ordered one more test a CT scan which showed what was really going on.

"He went one step further and did the CT scan and … he is the first person to save my life," Johnson said.

Johnson was then taken to Toronto General Hospital, where Ouzounian performed surgery to repair the tear.

Without that surgery, Johnson could have died. The dissection significantly limits the amount of blood flowing from the heart. Ouzounian pegs the risk of dying with a Type A aortal dissection at one to two per cent per hour.

"The sooner we get the patient to the operating room, the better our chances of saving the patient's life," she said.

The deaths of actors Alan Thicke and John Ritter have been attributed to aortic dissections.

A recent study found that the number of aortic dissections in Ontario has risen steadily since 2002. Between that year and 2014, there were a total of 5,966 dissections reported in the province.

Dr. Scott McClure, the lead scientist on the study and a cardiac surgeon at the University of Calgary's Foothills Medical Centre, believes Canada as a whole is seeing a similar trend.

Why that is happening remains an open question. McClure suspects it has something to do with Canada's aging population, since high blood pressure is a known risk factor for aortic tears.

"If you are going to live longer, you are going to have a higher time to be susceptible to higher blood pressure, therefore you have an increased risk of dissections," he said.

Johnson, who recently returned to nursing, is on her own mission to warn others about the risk of dissections, and the need to press for extra tests in patients with unexplained chest pain like hers.

"If somebody goes into the (ER) with chest pain, the only true diagnosis (for an aortic dissection) is a CT scan so if all the other tests fail, take that step and have a CT done -- push for it," she said.

With a report from CTV News' medical affairs specialist Avis Favaro and producer Elizabeth St. Philip