Ontario Case on Product Liability Shows the Immense Scope of a Class Action Trial

In a highly anticipated decision released on June 26, 2012, the Ontario Superior Court of Justice ruled in favour of the defendants in Andersen v. St. Jude Medical, Inc., Ontario’s first medical product liability class action trial. As more cases are being certified as class proceedings, Andersen provides a window into what litigants can expect from a class action trial: enormous complexity, scope and cost.


The class’s claims stemmed from St. Jude’s recall, in January 2000, of mechanical heart valves that were coated with Silzone, which was designed to reduce the growth of bacteria and prevent infections resulting from heart-valve surgery. Some time after the valves had been on the worldwide market, a clinical trial showed a "small but statistically significant increase" in explants resulting from a specific complication in patients who had received the valve. St. Jude immediately (and voluntarily) withdrew the products from the market. The plaintiffs alleged, among other things, that St. Jude had failed to properly test and evaluate Silzone’s safety before marketing products with the coating, and failed to properly warn of its risks, in light of information on adverse events it was receiving from some physicians and clinical trials.

The action was certified as a class proceeding in 2003 and went to trial in 2010 and 2011. The trial lasted 138 days and included testimony from 40 witnesses, 23 of whom were experts from 14 different scientific and medical disciplines. The record comprised close to 2300 documents, and the parties’ written closing submissions ran in excess of 2000 pages. Oral closings occupied an additional eight days.

The Decision

In a 200-page decision, Justice Lax found in favour of the defendants on all issues of liability. While it was hoped that the decision would answer questions about the scope of the developing "waiver of tort" doctrine, given her finding of no liability Justice Lax did not decide that question. However, she did observe that it was a policy-laden matter that should be resolved. She disagreed with the view that resolution required a trial, noting that the policy issues had not been illuminated by the extensive factual record before her; she suggested that legislative consideration might be more appropriate. Apart from waiver of tort, the case illustrates the application of many principles of negligence law to a large and complex common issues trial.

Order to Determine the Common Issues

The first common issue for the Court’s consideration was whether St. Jude had met the standard of care, followed by issues related to causation. The defendants argued that the Court should decide issues of causation first and only then consider the standard of care where it related to an act that caused harm. Justice Lax was not persuaded that dealing with causation first would allow her to focus on the standard of care analysis.

General vs Specific Causation

The Court held that a class action requires the causation analysis to be divided into consideration of general and specific causation. In a common issues trial, the question was not whether Silzone caused impaired healing, but whether it could cause the adverse effect. The Court recognized that the plaintiffs had to firmly prove their case on a balance of probabilities and held that the evidence did not meet that standard.

The plaintiffs relied chiefly on a 14-patient "clinico-pathological" study, which Justice Lax described as involving reviewing records and pathology of the patients and correlating the findings. She found that this type of study (a "scorecard on 14 individual patients") was of little assistance in answering general causation questions. In addition, the types of medical complications potentially suffered by the class were risk factors for all recipients of mechanical valves, and the defendants’ experts had provided evidence of alternative causes for the complications identified in the study.

Similarly, Justice Lax found that epidemiological evidence should not be considered determinative of  causation in individuals. Simply because the evidence demonstrated a statistically significant increase in the risk of a complication in Silzone patients, it could not be concluded that all Silzone patients who suffered the complication would not have suffered it but for Silzone.

Duty to Warn

Although she found that a statistically significant increase in certain complications emerged between the time when the Silzone valves went to market and their recall, she held that this did not give rise to an obligation to warn of increased risks. The complications in issue were already the subject of warning in the labelling and in the physicians’ manual. Further, since the relative risk had not doubled, she held that it was not material to either the demonstration of causation or the duty to warn.

Appropriate Inferences of Causation

The plaintiffs argued that the Court should find that the "totality of the evidence" supported an inference that Silzone caused medical complications. This argument was based on a line of Supreme Court of Canada cases beginning with Snell v. Farrell, in which the Court stated that causation did not have to be determined by scientific precision and in some cases an inference of causation could be drawn without positive scientific proof.

Justice Lax rejected these arguments. She held that Snell applied only where the defendant had not adduced evidence contrary to a plaintiff’s claim. Justice Lax endorsed a British Columbia Court of Appeal decision in which the Court held that where both parties led expert medical evidence of causation, a trial judge cannot draw a "common sense inference" of the cause of the medical complication. In this case, the defendants had led a "considerable amount of evidence contrary" to an inference of causation.

Importance of Expert Witnesses

Justice Lax’s analysis of both the standard of care and causation was highly fact specific Her analysis demonstrates the importance of expert testimony regarding industry standards and practices and the interpretation of data related to causation. For example, Justice Lax found that the expert witness who provided the study that was the "causal lynchpin" of the plaintiffs’ case lacked neutrality, and that he testified as an advocate of the plaintiffs’ theory. Where his views differed from those of the defendants’ experts, his views were given little weight.


This decision will be welcomed by defendants in large product liability actions for its approach to evaluating evidence of causation, its recognition of the hierarchy of scientific studies and its analysis of the appropriate circumstance to infer causation. It gives plaintiffs and defendants much to consider in evaluating the strengths and weaknesses of product liability class actions.



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