Shortage of drug used for heart tests is resulting in delayed scans for patients, doctor says


An important medication used to perform tests on the heart is in low supply in Canada, meaning patients will have to wait even longer to find out if they have coronary artery disease, says a Toronto-based doctor.

The antiplatelet medication, called dipyridamole, is used to artificially relax arteries in the heart and dilate blood vessels so doctors can monitor blood flow through the heart muscle during a stress test. It is often used on patients who are unable to exercise for the test due to mobility challenges, or those who have cardiovascular problems. The tests are also known as myocardial perfusion scans.

Dr. Christopher Overgaard, director of invasive cardiology at Southlake Regional Health Centre, told CTV’s Your Morning on Monday the shortage is a “big deal” as it will force doctors to delay myocardial perfusion scans for patients.

“It’s going to force us to really change which patients are prioritized. And it’s not fun to have to do that because, really, everybody that has had the test order needs it done,” said Overgaard.

Across Canada, patients have experienced significant wait times for important medical procedures or tests, and some have died while waiting for assistance.

Between 2021 and 2022, at least 13,581 patients died while waiting for surgeries, procedures and diagnostic scans, which represents a 23 per cent increase compared to the year before, according to a report from published in December 2022.

This drug shortage could force some patients to wait longer before receiving the help they need, said Overgaard.


Health Canada announced a shortage of dipyridamole injections in June due to production delays by the manufacturing company Fresenius Kabi Canada, according to Drug Shortages Canada. The company reported contract customers will receive 50 per cent of their “historical monthly demand” before a supply interruption takes effect from Aug. 1 to 18.

This is the second major cardiology drug shortage in Canada in recent months. Nitroglycerin spray, used to treat pain and improve blood flow, has been in short supply since late February.

The low supply, classified as Tier 3 due to its importance, came as a surprise to Overgaard who also owns a cardiac clinic in Toronto.

“It kind of came out of nowhere. So we were all very surprised about this,” said Overgaard, who explained the first time he heard about the shortage was from his own laboratory after requesting multiple tests.

“Our own lab will call us and say, ‘Unfortunately, we can’t do this test in a timely fashion because of this delay,’” he said.

To mitigate the shortage of this crucial drug in the country, Health Canada will allow dipyridamole to be imported from the United States until late August.

“It’s actually not very clear to us and users why this is happening,” said Overgaard. “It seems to be the usual ‘supply-chain problems,’ which we don’t really understand as end users.”

The Toronto-based doctor said there’s been an increase in the number of patients getting tested for cardiology or cardiac conditions since the pandemic started.

To hear the full interview click the video at the top of this article. 


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