Aortic Dissection Diagnostic Delay: Breach and Causation in Time-Critical Emergency Claims

Aortic dissection represents a devastating cardiac emergency, demanding rapid diagnosis and intervention to optimise patient outcomes. For solicitors handling clinical negligence claims involving allegations of diagnostic delay, the complexities of breach of duty and causation in such time-critical scenarios are considerable. Specialist medico-legal assessment provides clarity on the clinical standard of care and the impact of alleged delays.

Understanding Aortic Dissection: Clinical Imperatives

Aortic dissection occurs when a tear in the inner layer of the aorta allows blood to surge between the layers, forcing them apart. This can compromise blood flow to vital organs and lead to catastrophic complications, including rupture, acute heart failure, stroke, and organ ischaemia. The classification into Stanford Type A (involving the ascending aorta) and Type B (distal to the subclavian artery) dictates management, with Type A typically requiring urgent surgical repair and Type B often managed medically.

The cardinal feature is sudden, severe pain, often described as tearing or ripping, typically in the chest, back, or abdomen. Presentations can be atypical, mimicking myocardial infarction, musculoskeletal pain, or neurological events, posing significant diagnostic challenges. Red flags include migratory pain, pulse deficits, new aortic regurgitation, neurological signs, and hypotension or hypertension. The gold standard for diagnosis is a contrast-enhanced computed tomography (CT) aortogram.

Critically, the mortality rate for Type A aortic dissection increases by approximately 1-2% per hour if untreated. This underscores why diagnostic delay can profoundly affect prognosis, forming the basis of many claims.

Breach of Duty in Diagnostic Delay

Establishing breach of duty requires assessment of whether care fell below the standard of a reasonably competent clinician, per *Bolam* and *Bolitho* principles. Common allegations include:

• Inadequate history-taking: Missing key symptoms like sudden onset or tearing quality of pain.
• Incomplete physical examination: Failing to identify pulse deficits or new heart murmurs.
• Narrow differential diagnosis: Not considering aortic dissection despite red flag symptoms.
• Delayed investigations: Ruling out myocardial infarction but not progressing to CT aortogram when suspicion remains.
• Imaging misinterpretation: Overlooking subtle signs on chest X-ray or initial CT findings.
• Delayed referral: Failure to expedite transfer to specialist cardiac centres for Type A dissection.

The expert witness scrutinises medical records to reconstruct the timeline and assess clinical decisions at each stage.

Causation: Complexities in Time-Critical Scenarios

Causation presents the greatest challenge in these claims. Given the high intrinsic mortality of aortic dissection, claimants must demonstrate that the alleged breach materially contributed to the adverse outcome or that timely diagnosis would have significantly improved prognosis.

The ‘material contribution’ test (*Bailey*, *Williams*) requires showing the negligent delay made a more than negligible contribution to the injury. This differs from the ‘but for’ test, which is often difficult to satisfy where the underlying condition carries high risk. Expert analysis involves:

1. Precisely quantifying the diagnostic and treatment delay.
2. Evaluating the patient’s condition at the point correct diagnosis should have occurred.
3. Estimating likely outcome with optimal, timely care.
4. Determining how delay exacerbated the condition or reduced chances of favourable outcome.

The material contribution test remains the robust framework for addressing causation where negligence adds to the risk of injury.

The Role of the Consultant Cardiologist Expert Witness

Early instruction of an experienced consultant cardiologist expert witness is crucial. Their expertise includes:

• Reviewing the entire clinical pathway from pre-hospital care to specialist interventions.
• Evaluating whether aortic dissection was appropriately considered in the differential diagnosis.
• Assessing timeliness and appropriateness of diagnostic imaging.
• Opining on whether the standard of care was met at each stage.
• Providing robust causation analysis considering inherent risks versus impact of delays.
• Preparing detailed CPR Part 35 compliant reports for litigation.

Practical Guidance for Solicitors

Solicitors should focus on gathering comprehensive medical records, including emergency department attendances, GP consultations, ambulance records, and imaging reports. A clear chronological timeline is crucial. Specialist input may be needed from cardiac surgeons if surgical intervention is contested.

The time-critical nature means even short delays can have significant consequences. Understanding clinical emergency pathways and causation arguments is essential for effective case management.