McMullan Estate v Naom Estate: Mild Aortic Root Dilation, ED Chest Pain, and the Limits of Foreseeability

Aortic dissection is one of the canonical missed-diagnosis cases in modern emergency medicine. The condition is uncommon (roughly 3 cases per 100,000 person-years in population-based studies). It is rapidly lethal in its acute form: untreated Stanford Type A dissections (those involving the ascending aorta) carry a mortality rate that increases by approximately one percent per hour after symptom onset, with most deaths occurring within the first 48 hours. It is famously difficult to recognize: fewer than half of patients present with the classic triad of tearing chest pain, blood pressure differential between the arms, and widened mediastinum on chest X-ray. Many patients present with symptoms that overlap with much more common conditions (acute coronary syndrome, pulmonary embolism, musculoskeletal chest pain, hypertensive emergency). The combination of low prevalence, high lethality, and atypical presentations makes aortic dissection a recurring subject of malpractice litigation.

Estate of Kevin John McMullan v Estate of Dr Nashwan Albeer Ibrahim Naom, 2025 ONSC 254, released by Justice Robert Centa of the Ontario Superior Court of Justice on January 13, 2025, is a defendant-favourable Ontario decision involving exactly this clinical context. Mr. McMullan died at age 56 from an aortic dissection. The family brought a malpractice action against two physicians: the internal medicine specialist who had managed his hypertension and cardiovascular risk factors from late 2012 through mid-2013 (approximately three years before the fatal event), and the emergency department physician who had seen him for chest pain and hypertension on February 29, 2016 (approximately two months before the fatal event). The trial judge dismissed the action against both physicians. Damages had been settled in advance at $596,500; the trial proceeded on standard of care and causation only.

The case is a clean illustration of two recurring frameworks in cardiovascular malpractice cases. The first is the “temporal disconnection” framework: where a physician’s involvement in the patient’s care is separated from the catastrophic event by a substantial time interval, the causation analysis must account for what could reasonably have been foreseen and prevented at the time of the physician’s involvement. The second is the “reassuring investigation” framework: where the contemporaneous investigations were objectively reassuring, the standard of care does not require pursuing additional investigations on the chance that a rare and catastrophic condition might be present.

The case is also doctrinally notable for the dual-defendant structure, with one defendant (Dr. Naom) having died between the events at issue and the trial. The procedural framework for actions against the estate of a deceased defendant operates through the Trustee Act, RSO 1990, c T.23, which permits actions to continue against the estate of a deceased person.

The case introduces a substantial new practice area to the cluster: aortic dissection, aortic root dilation, and the framework for assessing risk in patients with cardiovascular abnormalities short of overt dissection.

Clinical context — aortic dissection and aortic root dilation

A brief clinical overview is useful for the legal analysis.

Aortic dissection. The aorta is the largest artery in the body, carrying blood from the heart to the rest of the circulation. The aortic wall has three layers: the intima (inner), the media (middle), and the adventitia (outer). An aortic dissection occurs when a tear in the intima allows blood to enter the media, creating a false lumen between the layers. The dissection can extend along the aorta and can cause catastrophic complications: rupture (with massive internal bleeding); occlusion of branch vessels (with stroke, kidney failure, limb ischemia, or visceral ischemia); aortic valve regurgitation (where the dissection extends to the root); or cardiac tamponade (where blood accumulates in the pericardial sac surrounding the heart).

The Stanford classification divides aortic dissections by location: Type A involves the ascending aorta (regardless of where the primary tear is located) and Type B is limited to the descending aorta. Type A dissections are surgical emergencies requiring immediate repair; Type B dissections are typically managed medically unless complications develop. The two types have very different mortality profiles: Type A is rapidly lethal without surgery, while Type B can often be managed with aggressive blood pressure control.

Aortic root dilation. The aortic root is the segment of the aorta immediately above the aortic valve. Aortic root dilation refers to enlargement of this segment beyond the normal size range for the patient’s body size and age. Dilation can be primary (related to connective tissue disorders such as Marfan syndrome, bicuspid aortic valve, or familial thoracic aortic aneurysm syndromes) or secondary (related to hypertension, atherosclerosis, or aging). The clinical significance of aortic root dilation depends on the degree of dilation, the rate of growth, the presence of associated valve disease, and the patient’s overall risk profile.

The clinical management of aortic root dilation is typically structured around thresholds:

• Mild dilation (typically less than 4.0-4.5 cm) is usually managed with risk factor control (blood pressure management, lifestyle modification) and periodic monitoring with echocardiography
• Moderate dilation (4.5-5.0 cm) is typically managed with closer monitoring and consideration of additional imaging
• Significant dilation (greater than 5.0-5.5 cm for adults without connective tissue disorders) is typically managed with surgical referral for consideration of prophylactic repair

The thresholds vary somewhat across guidelines and clinical contexts. The Canadian Cardiovascular Society position statement on thoracic aortic disease and the relevant ACC/AHA guidelines provide structured approaches but acknowledge substantial clinical judgment in individual cases.

Hypertension and aortic disease. Sustained hypertension is the most common acquired risk factor for aortic disease. Adequate blood pressure control is the foundation of management for both prevention and the established condition. The combination of hypertension and aortic dilation places the patient at increased risk and requires structured management.

The challenge of aortic dissection in the ED. Patients with acute aortic dissection often present to the emergency department with symptoms that overlap with more common conditions. The clinical challenge is to identify the relatively small subset of patients with aortic dissection from among the much larger population with acute chest pain. The Aortic Dissection Detection Risk Score (ADD-RS) is a validated clinical decision tool that incorporates predisposing conditions, pain features, and physical examination findings to stratify risk. Patients with high risk scores typically require advanced imaging (CT angiography is the standard) regardless of other reassuring findings. Patients with low risk scores can typically be managed with standard workup and observation. The framework provides structure for the SOC analysis in any ED chest pain case where aortic dissection is in the differential.

The facts

The patient. Mr. Kevin John McMullan was 56 years old at the time of his death on May 3, 2016. He had a history of hypertension and atrial fibrillation. He was followed by a family physician (Dr. Blanchard) in addition to the various specialists involved in the events at issue.

The November 2012 walk-in clinic visit. On November 5, 2012, Mr. McMullan presented to a walk-in clinic feeling unwell. He was assessed and found to have high blood pressure and an irregular heartbeat. He was sent to the emergency department at Leamington Hospital. The ED physician (Dr. Sarfraz) initiated treatment with metoprolol (a beta-blocker commonly used for both hypertension and rate control in atrial fibrillation) and referred Mr. McMullan to Dr. Naom, an internal medicine specialist, for outpatient consultation.

The November 28, 2012 echocardiogram. An echocardiogram was performed on November 28, 2012. The findings included:

• Mild aortic root dilation
• Atrial fibrillation
• Tricuspid regurgitation (leakage of blood backward through the tricuspid valve)
• Elevated right ventricular systolic pressure (a marker of pulmonary hypertension)
• Mild concentric left ventricular hypertrophy (a thickening of the left ventricular wall typically associated with longstanding hypertension)

The findings together described a patient with longstanding hypertension affecting the heart and vasculature. The aortic root dilation was specifically characterized as mild.

The December 13, 2012 consultation. Dr. Naom met with Mr. McMullan on December 13, 2012. The clinical assessment included:

• Mr. McMullan was asymptomatic (no chest pain, no shortness of breath, no palpitations)
• The aortic root dilation was assessed as not clinically significant
• A medication change was made (from ramipril to losartan) because of a skin rash that was attributed to the ramipril

The January 24, 2013 follow-up. A follow-up consultation identified that Mr. McMullan was taking his metoprolol once daily instead of the prescribed twice daily. Dr. Naom addressed medication compliance.

The February 25, 2013 follow-up. Mr. McMullan’s blood pressure and heart rate were within the target range. He reported feeling well.

The May 28, 2013 sign-off. At his final consultation with Dr. Naom on May 28, 2013, Mr. McMullan was clinically stable with well-controlled blood pressure and no health complaints. Dr. Naom sent a sign-off letter to Dr. Blanchard (the family physician) and returned Mr. McMullan’s care to the family physician.

The intervening period. Between May 2013 and February 2016, Mr. McMullan was followed by his family physician. The events of this period are not at issue in the action; no defendant from this period is named.

The February 29, 2016 ED visit. On February 29, 2016, approximately two months before his death, Mr. McMullan attended the Leamington Hospital emergency department. He was seen by Dr. El Jaoudi. The clinical picture included high blood pressure and chest pain. The initial assessment was performed at 23:50. Investigations ordered included:

• Complete blood count
• Glucose
• Electrocardiogram
• Chest X-ray

All investigations were normal. The ECG specifically did not show signs of myocardial ischemia. The chest X-ray did not show any acute abnormalities including no widened mediastinum (a classic but insensitive sign of aortic dissection).

Dr. El Jaoudi initiated treatment with labetalol (a beta-blocker used acutely for hypertension). At reassessment at 02:00, Mr. McMullan’s blood pressure was well controlled. The clinical decision was made to discharge him with instructions to follow up with his family physician within one week.

The fatal event. On May 3, 2016, Mr. McMullan suffered a 1.5 cm tear in his aorta. The dissection caused sudden death. He was 56 years old.

The action. The family commenced a malpractice action against Dr. Naom (the internal medicine specialist who had managed Mr. McMullan in 2012-2013) and Dr. El Jaoudi (the emergency department physician who had seen Mr. McMullan in February 2016). Dr. Naom died at some point between the events and the trial; the action proceeded against his estate. Damages were settled prior to trial at $596,500 inclusive of all taxes, pre-judgment interest, and subrogated claims. The trial proceeded on standard of care and causation only.

The legal framework — standard of care for Dr. Naom

The trial judge addressed the standard of care for the internal medicine specialist on five distinct points.

Echocardiogram interpretation. The trial judge found that Dr. Naom’s interpretation of the November 2012 echocardiogram was correct. The mild aortic root dilation was correctly identified, characterized, and integrated into the overall clinical picture.

The decision not to recommend additional aortic imaging. This was the central SOC question for Dr. Naom. The plaintiffs’ theory was that the standard of care required further imaging of the aorta (CT angiography or MR angiography) to fully characterize the aortic root dilation and to identify any associated abnormalities that might portend dissection. The trial judge accepted the defence position that the mild aortic root dilation as documented on the echocardiogram did not require further imaging at the time. The clinical framework: mild dilation in the absence of associated risk factors (connective tissue disorder, family history of aortic disease, rapid progression) is managed with risk factor control and periodic echocardiographic monitoring rather than escalation to advanced imaging.

Management of hypertension and cardiovascular risk factors. The trial judge found that Dr. Naom’s management of Mr. McMullan’s hypertension and overall cardiovascular risk factors met the standard of care. The management included appropriate medication selection, dose titration, response to a medication-related adverse effect (the rash from ramipril, with the substitution to losartan), follow-up at appropriate intervals, and attention to medication compliance.

Interpretation and management of the stress test and Persantine MIBI. Mr. McMullan had undergone stress testing and Persantine MIBI testing (a nuclear medicine cardiac stress test used in patients who cannot exercise). The trial judge found that Dr. Naom’s interpretation and management of both tests met the standard of care. The implication: the cardiac workup had appropriately addressed the question of ischemic heart disease and had not identified a need for additional aortic-focused investigation.

The conclusion that the aorta was normal. The trial judge specifically accepted Dr. Naom’s conclusion that Mr. McMullan’s aorta was normal in the relevant sense for clinical management at that time. The trial judge rejected the plaintiffs’ contrary evidence on this point.

Recommendations for ongoing care. The trial judge found that Dr. Naom’s recommendations for ongoing care (return to family physician for routine follow-up; no need for additional aortic imaging or testing) were reasonable. The sign-off letter to Dr. Blanchard, the discharge from internal medicine follow-up, and the absence of any specific instruction for additional aortic monitoring were all within the standard of care.

The conclusion: Dr. Naom met the standard of care in all aspects of his management of Mr. McMullan.

The legal framework — standard of care for Dr. El Jaoudi

The trial judge addressed the standard of care for the emergency department physician on four distinct points.

The differential diagnosis approach. Dr. El Jaoudi assessed Mr. McMullan for chest pain in the setting of hypertension. The relevant differential at the bedside included acute coronary syndrome, hypertensive emergency, pulmonary embolism, aortic dissection, and other less common etiologies. The trial judge found no breach in Dr. El Jaoudi’s approach. The clinical context did not include a significant history of aortic dilatation that would have specifically elevated aortic dissection in the differential (the prior diagnosis of mild aortic root dilation from 2012, four years earlier, was not in the picture in any clinically actionable way).

Ruling out end organ damage. A hypertensive emergency is characterized not just by elevated blood pressure but by acute end organ damage (cardiac, renal, neurological, retinal, vascular). The standard ED workup includes assessment for end organ damage through clinical examination and targeted investigations. The trial judge found that Dr. El Jaoudi had successfully ruled out end organ damage: the clinical findings were reassuring; the laboratory investigations were normal; the imaging was normal; the ECG showed no signs of acute ischemia.

The decision not to perform fundoscopy or order urinalysis. Fundoscopy (direct visualization of the retina to look for hypertensive retinopathy) and urinalysis (assessment for proteinuria, a marker of hypertension-related renal damage) are recognized components of the assessment for hypertensive emergency. The plaintiffs alleged that the absence of these investigations breached the standard of care. The trial judge rejected this. The findings: fundoscopy is a challenging procedure to perform reliably in the ED setting, and the indicators for it in this case were not present; urinalysis was similarly not specifically indicated. The standard of care is not satisfied by performing every conceivable investigation but by performing the investigations that the clinical picture requires.

The decision not to order serial ECG or troponin testing. Serial ECG and troponin testing are typically used to evaluate for acute coronary syndrome in patients with chest pain. The plaintiffs alleged that the absence of these investigations breached the standard of care. The trial judge rejected this. The initial test results were reassuring; the ECG did not show signs of myocardial ischemia; the clinical picture did not suggest acute coronary syndrome. The standard ED workup for chest pain involves a calibrated response: where the initial workup is reassuring and the clinical picture is not concerning, escalation to repeated testing is not required.

The discharge decision. The trial judge found that Dr. El Jaoudi had provided appropriate instructions for discharge and follow-up care. The recommendation to follow up with the family physician within one week was within the standard of care. The decision to discharge given the reassuring investigations and stabilized blood pressure was reasonable.

The conclusion: Dr. El Jaoudi met the standard of care in all aspects of the February 29, 2016 ED visit.

The legal framework — causation

The trial judge dismissed the action on the standard of care findings, with the result that no formal causation analysis was strictly necessary. The defence position on causation, however, was substantial and would have provided an alternative basis for dismissal:

Temporal disconnection from Dr. Naom’s care. Approximately three years passed between Dr. Naom’s discharge of Mr. McMullan to family physician care (May 28, 2013) and the fatal aortic dissection (May 3, 2016). The plaintiff’s theory required establishing that additional aortic imaging in late 2012 or early 2013 would have identified a clinically actionable finding (an aortic abnormality requiring intervention or much more intensive monitoring), that the resulting clinical pathway would have continued to identify and manage that abnormality through the intervening period, and that the resulting management would have prevented the fatal event in 2016. Each step in this chain involves substantial counterfactual reconstruction. The “counterfactual would not have helped” framework now well-established in the cluster (Yang v Freed, Lorencz v Talukdar, Graham v Bridgepoint Health) operates here: the plaintiff cannot establish on the balance of probabilities that earlier intervention would have changed the outcome four years later.

Temporal disconnection from Dr. El Jaoudi’s care. Approximately two months passed between Dr. El Jaoudi’s February 2016 ED visit and the fatal aortic dissection. The plaintiff’s theory required establishing that a CT angiogram or other advanced imaging at the February ED visit would have identified an acute aortic process that was already underway, or a chronic aortic abnormality that would have led to clinical pathways preventing the May event. The defence position: the February presentation was a hypertensive episode, the workup was reassuring, and there was no clinical indication for advanced aortic imaging at that visit. The aortic dissection that ultimately killed Mr. McMullan was not foreseeable from the available clinical picture in February.

The defence framework operates through the “limits of foreseeability” framework. The standard of care does not require physicians to anticipate every possible adverse outcome. It requires physicians to act reasonably on the clinical picture as it presents. Where the clinical picture is reassuring and the disease in question is rare, the failure to investigate further does not breach the standard of care, and the eventual occurrence of the rare disease does not establish causation by the earlier non-investigation.

The doctrinal anchors

Several doctrinal anchors emerge from the case.

The “limits of foreseeability” framework. Modern Canadian malpractice law operates on the principle that the standard of care is the standard of a reasonable physician in the circumstances. Where the circumstances do not include indicators of a rare and catastrophic condition, the standard of care does not require pursuing investigations on the chance that such a condition might be present. The framework parallels the Supreme Court of Canada’s foreseeability framework in negligence generally (the harm must be reasonably foreseeable) and applies it specifically to the diagnostic workup question.

The “reassuring investigation” framework. Where the initial investigations are objectively reassuring, the standard of care does not require escalating to additional investigations. The reasoning runs through the ED chest pain analysis specifically (where the framework supports the discharge decision on reassuring workup) and through the outpatient cardiac assessment analysis (where the framework supports the absence of additional aortic imaging on reassuring echocardiogram). The framework is bounded: where the initial investigations are not reassuring, or where the clinical picture suggests a specific concern, escalation is required.

The “temporal disconnection” framework. The longer the interval between the alleged breach and the catastrophic event, the harder the causation analysis becomes. The intervening period typically involves other clinical encounters, opportunities for identification of the developing problem, and decisions by other providers. The plaintiff has to establish on the balance of probabilities that the alleged breach affected the outcome despite the intervening period. McMullan v Naom illustrates the framework operating across two distinct intervals: three years for the internist and two months for the ED physician.

The “mild aortic root dilation” framework. The clinical management of mild aortic root dilation is typically focused on risk factor control and periodic monitoring rather than advanced imaging or surgical referral. The framework reflects the natural history of mild aortic disease (most patients with mild dilation do not develop dissection or rupture) and the limited yield of advanced investigations in this population. The framework provides structure for SOC analysis in cases involving aortic findings short of overt dissection.

The ED chest pain workup framework. The standard ED workup for chest pain in a patient with hypertension involves a structured approach: clinical assessment for high-risk features; targeted investigations (ECG, chest X-ray, basic laboratory panel, often troponin); reassessment after initial stabilization; calibrated decisions about escalation to advanced imaging based on the cumulative clinical picture. McMullan v Naom illustrates the framework operating in a defendant-favourable context: a reasonable workup, reassuring findings, and a discharge with appropriate continuity instructions. The framework parallels the Aortic Dissection Detection Risk Score (ADD-RS) and similar structured tools used in modern ED practice.

The “back to family physician” handoff framework. Internal medicine specialists who provide episodic outpatient management typically return patients to family physician care once the acute clinical issue has been addressed. The handoff framework includes a sign-off letter to the family physician, a clear statement of the ongoing management plan, and the assumption that the family physician will provide continuing oversight. The framework does not impose an ongoing duty on the internist to monitor the patient after discharge unless specific arrangements are made. McMullan v Naom illustrates the framework operating in a defendant-favourable context: the sign-off was appropriate, the management plan was clear, and the internist had no further duty of care after the handoff.

The “follow up with family physician” ED discharge framework. Discharge from the ED with instructions to follow up with the family physician is the standard pattern for stable patients whose acute clinical issue has been addressed and who do not require ongoing hospital-level care. The framework does not impose an ongoing duty on the ED physician beyond the discharge instructions. Where the discharge is reasonable on the available clinical picture, subsequent adverse events do not retroactively make the discharge negligent.

The estate-v-estate procedural framework. Where the defendant physician has died between the events and the trial, the action continues against the estate under the Trustee Act, RSO 1990, c T.23. The estate is represented by the executor or estate trustee. The proof and procedural framework is essentially the same as against a living defendant, with some adjustments for the witness availability question (the deceased physician’s evidence is no longer directly available). The framework operates similarly across other estate-v-estate cases in malpractice litigation.

The dual-defendant outcome. McMullan v Naom involves two defendants in different specialties at different time points. Both prevailed independently. The pattern is doctrinally common in malpractice cases involving multiple care providers across the patient’s clinical course. The SOC analysis runs separately for each defendant on the specific clinical question that defendant faced.

The damages-settled-in-advance pattern. The $596,500 damages settlement (inclusive of all taxes, pre-judgment interest, and subrogated claims) is modest for a wrongful death claim involving a 56-year-old. The pattern suggests that the parties anticipated liability would be the principal contest and that the damages dimension could be addressed by negotiation without trial. The pattern is doctrinally common in malpractice cases where the contested question is principally legal and medical rather than damages-related.

Why this case matters

For families of patients who have died from aortic dissection. Mr. McMullan’s family pursued a malpractice action through to trial and lost. The pattern is unfortunately common in aortic dissection cases. The clinical reality is that aortic dissection is difficult to anticipate from non-acute presentations, and the standard of care does not require physicians to investigate every patient with hypertension or mild aortic findings for the rare possibility of subsequent dissection. The legal framework requires more than the bad outcome: it requires a specific breach by a specific defendant, causation by that breach, and damages flowing from the breach.

For families considering similar cases, several practical points emerge:

The “should have ordered more tests” framing is often inadequate. Plaintiffs in missed-diagnosis cases often frame the breach as a failure to order additional investigations. The framing does not engage the SOC analysis directly. The question is not whether additional investigations could have been ordered but whether the standard of care required them on the clinical picture as it presented. Where the clinical picture was reassuring, the standard of care typically does not require escalation.

Temporal distance from the catastrophic event matters. Where the physician’s involvement is separated from the event by months or years, the causation analysis becomes substantially harder. The plaintiff must establish that the alleged breach affected the outcome despite the intervening period. The framework parallels the Lorencz v Talukdar wait time framework, the Yang v Freed temporal mismatch framework, and the Graham v Bridgepoint Health same-treatment framework. All operate as variations of the counterfactual reconstruction problem.

Mild findings on echocardiogram do not typically support malpractice claims. Where the relevant clinical findings were specifically characterized as mild and were within the normal range of management for the underlying conditions, the SOC framework does not require escalation. The clinical management of mild aortic root dilation is well-structured around periodic monitoring rather than aggressive intervention.

For more on the general framework for evaluating these cases, see Suing for Medical Malpractice in Ontario: What You Need to Know and Why Many Medical Malpractice Cases Are Declined in Ontario.

For physicians and clinical teams. A few practical observations:

Document the clinical reasoning, not just the decisions. The SOC analysis turns substantially on what the chart reflects. Where a decision is made not to pursue additional investigations (no CT angiogram for mild aortic dilation; no serial troponin in reassuring chest pain), the chart should reflect the basis for the decision. The documentation is not just defensive practice; it is the record of the clinical reasoning that supports the SOC analysis.

Communicate transitions of care clearly. The sign-off letter from the internist to the family physician is an important feature of the McMullan v Naom SOC analysis. Where care is transitioned, the framework includes clear communication of the ongoing management plan, the rationale for the transition, and the expected role of the receiving provider.

The ED discharge decision is part of the SOC. Discharge from the ED with reasonable continuity instructions is not just an administrative step. It is a clinical decision that requires the same SOC analysis as the initial assessment and the investigative workup. Where the discharge is reasonable on the clinical picture as it presents, the SOC is met.

Bad outcomes happen even with appropriate care. Aortic dissection in a 56-year-old hypertensive patient with prior mild aortic dilation is a tragedy. The SOC framework does not transfer the consequences of every tragedy to the prior care providers. Where the care was appropriate, the SOC analysis supports that conclusion even when the outcome is catastrophic.

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Decision Date: January 13, 2025

Jurisdiction: Ontario Superior Court of Justice

Citation: Estate of Kevin John McMullan v Estate of Dr Nashwan Albeer Ibrahim Naom, 2025 ONSC 254 (CanLII)

Trial Judge: Justice Robert Centa

Outcome: Action dismissed against both defendants. The trial judge found that the internal medicine specialist who had managed the patient’s hypertension and cardiovascular risk factors in 2012-2013 (approximately three years before the fatal aortic dissection) had met the standard of care in interpreting the echocardiogram, in declining to recommend additional aortic imaging, in managing the hypertension and cardiovascular risk factors, in interpreting the stress test and Persantine MIBI, in concluding that the aorta was normal for clinical management purposes at that time, and in returning the patient to family physician care. The trial judge also found that the emergency department physician who had seen the patient in February 2016 (approximately two months before the fatal event) with chest pain and hypertension had met the standard of care in his differential diagnosis approach, in successfully ruling out end organ damage with appropriate investigations, in declining to perform fundoscopy or urinalysis (not indicated on the clinical picture), in declining to order serial ECG or troponin testing (initial workup reassuring; no signs of myocardial ischemia), and in discharging the patient with appropriate follow-up instructions to the family physician. Damages had been settled prior to trial at $596,500 inclusive of all taxes, pre-judgment interest, and subrogated claims.

Key authorities (implicit in the analysis): Wilson v Swanson, [1956] SCR 804 (standard for specialists); ter Neuzen v Korn, [1995] 3 SCR 674 (specialist standard); Clements v Clements, 2012 SCC 32 (but-for causation); Snell v Farrell, [1990] 2 SCR 311 (robust and pragmatic causation); Trustee Act, RSO 1990, c T.23 (continuation of actions against estates).