Purpose (background):
Sudden cardiac deaths (SCD) represent a significative part of fatalities in developed countries each year. Amongst postmortem investigations, MPMCTA (Multiphase post-mortem CT angiography) has proved to be a most useful tool to help identify SCDs. The detection of coronary arteries calcification, being a tell-tale sign of poor cardiovascular health, has been used at the CURML (Centre Universitaire Romand de M ́edecine L ́egale) as the main indication to perform PMCTA (post-mortem CT angiography). But day-to-day practice of forensic medicine is in need of an evidence-based decisional tool to guide investigations and to determine when to use PMCTA, particularly regarding logistical, time-related and financial reasons. The aim of this study was to determine the strength of coronary arteries calcification’s observation in native CT imaging as an indication to perform routine post-mortem CT angiography and to compare its forensic significance to other criteria of interest, in order to help correctly identify SCDs.
Materials and methods:
A retrospective analysis was carried out on 1091 individuals’ medico-legal autopsy reports and native CT reports (2015 to 2019 incl.). For every individual, multiple criteria of interest were recorded including coronary calcification in native CT imaging, sex, age, BMI (Body Mass Index) and external signs suggestive of sudden cardiac death such as hypostasis in the territory of the superior vena cava. In parallel, confirmed SCD cases were identified in the same population. The diagnostic value of every criterion of interest (considered as dichotomic factors) in identifying confirmed SCD cases was investigated and compared.
Results:
Prevalence of confirmed SCD cases is 12.7% (139 of 1091 cases) in the selected population. Coronary arteries calcification was detected in 52.4% of individuals (572 of 1091) among which 20.4% (117 of 572) were identified to have died of a confirmed SCD. The odds of an individual having died of SCD are significantly higher when coronary calcifications are detected (OR=5.81 [3.62; 9.32], p<0.01) and higher than those of an age >39 years (OR=4.34 [2.36; 7.98], p<0.01), those of individuals with a BMI >25 kg/m2 (OR=1.54 [1.07; 2.22], p=0.02), those of males (OR=2.72 [1.72; 4.31], p<0.01) and those of individuals with external signs suggestive of SCD (OR=2.82 [1.90; 4.17], p<0.01).
Negative predictive value (NPV) is the best indicator in the present study to compare variables. Although detection of calcifications is more specific than an age >39y (52.2 % [49.0; 55.4] vs. 29.1% [26.2; 32.1]), the NPV for both criteria is similar (95.8% [93.9; 97.1] vs. 95.8% [93.0; 97.6]). Although lower than those of previously cited variables, NPV of the presence of external signs of SCD is similar to the one of patients with a BMI >25 kg/m2 89.8% [88.6; 90.8] vs. 89.8% [87.5; 91.7]). Despite being low, PPV of the presence of external signs suggestive of SCD is higher than for all other variables (24.4% [19.6; 29.8]).
Conclusion:
Based on these results, we can admit that the detection of coronary calcifications on native post-mortem CT can’t be a sufficient criterion to perform PMCTA and must therefore always be interpreted in conjunction with other pre-autoptical data, especially with the clinical history and circumstances of death. External signs suggestive of SCD are an interesting way to complement post-mortem investigations.