Discharged the patient without reviewing critical imaging report
The Ontario Superior Court has dismissed a recent medical malpractice case involving a stroke patient, despite finding that the doctor was negligent.
On October 17, 2012, William Johnson suffered a stroke and was hospitalized. His condition eventually improved, and he was discharged on October 23. About a week later, on October 30, Johnson suffered a life-altering stroke.
Johnson sued Dr. Rose-Anne Vieira, a family physician who discharged him after his first stroke. Johnson alleged that Dr. Vieira failed to review a critical imaging report before she discharged him. He asserted that had Dr. Vieira reviewed this imaging report, he would not have been discharged and would have been given anticoagulation instead of antiplatelet therapy to prevent a second stroke.
While Johnson was given anticoagulation therapy before his second stroke, he suffered the second stroke. He argued that the delay in starting the treatment, which resulted from Dr. Vieira’s alleged failure to review the imaging report, caused the secondary stroke.
Dr. Vieira admitted that she failed to review the critical imaging report before discharging Johnson but argued that Johnson could not prove causation.
Legal test for causation
The Ontario Superior Court of Justice noted that the test for causation requires a “but for” analysis. The plaintiff must show that “but for” the defendant’s negligent act, the injury would not have occurred. The defendant’s negligence was necessary to bring about the injury, which requires a factual inquiry.
The court further explained that if the issue of causation relates to delayed medical diagnosis and treatment, the “but for” analysis requires the plaintiff to prove on a balance of probabilities that the delay “caused or contributed to the unfavourable outcome.” A common analytical approach to the causation analysis involves a three-part inquiry based on what likely happened, what would probably have occurred had the defendant not breached the standard of care, and where fault should be allocated.
The court explained that an ischemic stroke occurs when blood flow is blocked in part of the brain. Brain cells die when deprived of blood, which carries oxygen and glucose. Dissections of the cervical arteries are a well-established cause of stroke and a relatively common cause of strokes in young and middle-aged adults. The diagnosis of dissection is established by characteristic abnormalities on imaging studies of the blood vessels using CT, MRI, ultrasound, or catheter angiography.
Since most strokes arise from blood clots, there are two main anticlotting medications in clinical practice: antiplatelet drugs and anticoagulant drugs. The court noted that the expert evidence revealed the existence of a debate in the medical community around the comparative efficacy of anticoagulation therapy versus antiplatelet therapy in the prevention of secondary strokes stemming from vertebral artery dissections.
Breach of duty of care
The court found that Dr. Vieira discharged Johnson without reviewing the results of his MR angiogram of the head and neck (MRA). The court said that if Dr. Vieira had reviewed the MRA before discharging Johnson, she would have called Johnson’s neurologist, Dr. David Crisp, and Dr. Vieira would have asked for his opinion on how to proceed. Dr. Vieira would have deferred to Dr. Crisp’s opinion in terms of treatment decisions.
The court ruled that Dr. Vieira had a duty to Johnson to exercise reasonable care in ordering his discharge from the hospital on October 23. She breached the expected standards of care by failing to review the MRA report before discharging Johnson.
To determine causation, the court analyzed whether Johnson likely would have been hospitalized and placed on anticoagulant therapy had Dr. Vieira reviewed the MRA imaging report. The court also examined whether Johnson would probably not have had the second stroke if he had been on anticoagulant therapy as of the time he was discharged on October 23.
The court that had Dr. Vieira reviewed the MRA before Johnson’s discharge and informed Dr. Crisp about it, Dr. Crisp like would have commenced anticoagulation on October 23. The court was also satisfied that had Dr. Crisp advised Johnson to take anticoagulation therapy on October 23, Johnson would have likely consented. It was clear to the court that Dr. Crisp would probably have placed Johnson on anticoagulation therapy had he been aware of the critical imaging report on October 23.
However, the court was not satisfied that switching to anticoagulant therapy would likely have prevented Johnson’s second stroke. The court found that the evidence, taken as a whole, does not support the conclusion that Johnson’s second stroke would likely have been prevented had he been placed on the anticoagulant drug Heparin instead of the antiplatelet drug Aspirin at the time of his initial discharge from the hospital.
The court said, “At best, it may have possibly resulted in a different outcome, either better or perhaps even worse than the actual outcome. While I am cognizant that the plaintiffs need not prove causation with scientific precision, this is not a case where a common-sense inference can be used to bridge the evidentiary gap.”
The court concluded that the plaintiff failed to prove causation. Consequently, the court dismissed the case.