Acute Ischemic Stroke

Early on December 4, 2011, his condition worsened significantly, and at 3 a.m. he could not get out of bed. He returned to the emergency department at Trillium by ambulance. He was again assessed by Dr. Campbell who ordered another CT scan of the head to rule out a stroke. By noon Mr. Hasan had deteriorated so severely that he had to be intubated and admitted to the intensive care unit. He had suffered a devastating life-altering stroke that left him with severe long-term disabilities.

On December 8, 2011, five days after his initial symptoms, Mr. Hasan underwent an MRI of the brain and a CT angiogram of the head and neck. He was then diagnosed with a brain stem stroke and was placed on an anticoagulation protocol. It was noted that Mr. Hasan had very good collateral circulation around the area of the blood clot, which was what allowed him to survive the serious stroke.

The court found that the defendant breached the standard of care on December 3 and 4 by not taking a complete medical history, not conducting a complete physical examination and by not ordering a CT angiogram to rule out a stroke, among other things. The uncontested evidence was that a CT angiogram would have been the immediate test of choice on December 3-4.

The complex causation arguments are detailed in the judgment, and while there are a number of differences in the theories advanced by both sides, the difference that impacted the question of what treatments were available and how likely were they to be successful, was that of a clot.1 The plaintiff’s theory was that he suffered a dissection in the left vertebral artery that was the source of the formation of a clot that occluded his basilar artery and cut off blood flow to parts of his brain. The defence’s experts agreed that there was a dissection in the left vertebral artery, but opined that it was the dissection itself that extended and occluded multiple blood vessels cutting off the blood flow and causing a stepwise progressive stroke. This difference was critical to the causation finding. If a blood clot were involved, there would have been three options available to try to open the blockage created by the blood clot – intravenous administration of the clot-dissolving drug tPA, use of a catheter to pull out the clot, or the injection of a smaller dose of tPA directly into the clot through the tip of a catheter. If the defence’s opinion was preferred by the court and no clot was involved, the plaintiff’s claim would be dismissed because it would been very difficult to treat the plaintiff and obtain a positive outcome.2 Ultimately the court found that Mr. Hasan’s stroke was caused by a clot, and had he been diagnosed by CT angiogram on December 3 or 4, he would have had appropriate therapy that would have been successful.

Working With Your Experts

The Hasan judgement reads as a masterclass in how to work with your experts at several significant steps from initial selection of the expert all the way to preparation for cross-examination.


It goes without saying that careful selection of your experts is the starting point for success. In Hasan, in commenting on the complexity of the case, the court noted that nearly all of the experts were teachers, most of whom had received various teaching awards. They were able to explain their opinions and the science in clear and accessible terms that the court found helpful.3 Despite making that comment, when the defence invited the court to give no weight to the opinion of an expert who had fewer awards, recognitions, research, and publications than the defence’s highly accomplished doctors, the court pointed out that “awards and publications do not produce opinions; experience produces opinions.”4

While it may not always be possible to retain experts with a teaching background, what is clear is that it is necessary to work with your experts to ensure that their opinion can be expressed in clear and understandable terms. In Hasan the complicated causation theories on both sides were made even more accessible to the judge through demonstrative aids including medical illustrations and an animation. Although these were not entered into evidence, they were still noted by the judge to be useful in simplifying complex concepts.

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Brenda Osmond


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