Measuring pressure during coronary artery angiography in ex-vivo Hearts

Coronary artery disease (CAD) is the most common cause of sudden adult death. Diagnosis in life and after death is therefore crucial, but can be problematic and inaccurate. Post-mortem CT angiography (PMCTA) is attempting to address this, but its accuracy is still not fully established. In clinical practice, pressure measurements, recording drops in pressure across the stenosis, are now being used to determine physiological significance, as the degree of narrowing on imaging can be misleading. This study was designed to investigate the introduction of pressure measurement to PMCTA in order to understand the importance of re-pressurising vessels in the evaluation of CAD. Ex-vivo porcine hearts were used to develop the technique. Methods to introduce catheters and wires were investigated and a system was developed to suspend the heart, to enable pressure tests and CT scans. Consistent measurable pressures were achieved with good correlation of measured arterial pressure to delivered pressure in most cases. Pressure measurements were shown to be inaccurate in decomposed hearts, poor dissection and cannulation damaging the vessel, contamination of the vessels (e.g. by air) and malposition of the pressure measurement wire

Diagnostic accuracy of post-­‐mortem Computed Tomography with targeted Coronary Angiography (PMCTA) when used as the first-­‐line investigation for HM Coroner post-­‐mortem investigations: prospective, blind comparison to a gold standard study.

Background England and Wales have one of the highest frequencies of autopsy in the world. Implementation of post-mortem CT (PMCT), enhanced with targeted coronary angiography (PMCTA), in adults to avoid invasive autopsy would have cultural, religious, and potential economic benefits. We aimed to assess the diagnostic accuracy of PMCTA as a first-line technique in post-mortem investigations. Methods In this single-centre (Leicester, UK), prospective, controlled study, we selected cases of natural and non-suspicious unnatural death referred to Her Majesty's (HM) Coroners. We excluded cases younger than 18 years, known to have had a transmittable disease, or who weighed more than 125 kg. Each case was assessed by PMCTA, followed by autopsy. Pathologists were masked to the PMCTA findings, unless a potential risk was shown. The primary endpoint was the accuracy of the cause of death diagnosis from PMCTA against a gold standard of autopsy findings, modified by PMCTA findings only if additional substantially incontrovertible findings were identified. Findings Between Jan 20, 2010, and Sept 13, 2012, we selected 241 cases, for which PMCTA was successful in 204 (85%). Seven cases were excluded from the analysis because of procedural unmasking or no autopsy data, as were 24 cases with a clear diagnosis of traumatic death before investigation; 210 cases were included. In 40 (19%) cases, predictable toxicology or histology testing accessible by PMCT informed the result. PMCTA provided a cause of death in 193 (92%) cases. A major discrepancy with the gold standard was noted in 12 (6%) cases identified by PMCTA, and in nine (5%) cases identified by autopsy (because of specific findings on PMCTA). The frequency of autopsy and PMCTA discrepancies were not significantly different (p=0·65 for major discrepancies and p=0·21 for minor discrepancies). Cause of death given by PMCTA did not overlook clinically significant trauma, occupational lung disease, or reportable disease, and did not significantly affect the overall population data for cause of death (p≥0·31). PMCTA was better at identifying trauma and haemorrhage (p=0·008), whereas autopsy was better at identifying pulmonary thromboembolism (p=0·004). Interpretation For most sudden natural adult deaths investigated by HM Coroners, PMCTA could be used to avoid invasive autopsy. The gold standard of post-mortem investigations should include both PMCT and invasive autopsy. Funding National Institute for Health Research