A Study on Post-Mortem Assessment of Coronary Artery Disease and The Role of Clinical Cardiology Diagnostic Techniques in Further Development of Minimally Invasive Autopsy

Background: There have been significant developments in recent years towards the use of imaging-based post-mortem examinations. Such new approach has to accurately diagnose coronary artery disease and should aim to overcome various limitations of conventional methods in determining whether the disease identified is a likely cause of death.

Aim: This study aims to determine the accuracy of current post-mortem computed tomographic angiography (PMCTA) techniques in diagnosing coronary stenosis and systematically investigates the effect and implication of repressurisation of postmortem coronary arteries and the use of clinical cardiology diagnostic tools in this context.

Methods: PMCTA was systematically compared against histology to determine its accuracy in diagnosing the severity of coronary stenosis. A systematic study was performed to demonstrate the effect of repressurisation of post-mortem coronary arteries using coronary pressure wire and optical coherence tomography (OCT). Finally, a proof of concept work was undertaken in the application computational fluid dynamic (CFD) techniques to PMCTA.

Results: The accuracy of PMCTA to identify coronary stenosis was modest (sensitivity 30%, specificity 96%, PPV 65% and NPV 84%) compared to histology of collapsed postmortem vessels. Repressurisation significantly increased vessel area in post-mortem porcine (3.3±0.5 mm2 vs. 8.4±1.5 mm2, N=6) and cadaveric coronary arteries (4.26±3.47 mm2 vs. 5.74±5.38 mm2, P<0.001). However, compliance was significantly different among normal and atherosclerotic segments (35.94±20.44 vs. 20.30±15.30 mmHg-1x1000, P=0.006), systematically effecting stenosis severity assessment. Finally, CFD techniques could be applied to post-mortem images to derive information on pressure and flow.

Conclusion: This study identified potential areas of systematic error in the current gold standard in assessing coronary stenosis severity at autopsy. It also showed that PMCTA is a promising tool and, with addition of CFD techniques, can provide information on both anatomical and functional significance of a stenosis with the potential to become a new and improved gold standard.